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Earth and Planetary Sciences › Geophysics

Geological and Tectonic Studies in Latin America

Works Count: 36220

Description

This cluster of papers focuses on the geodynamic processes, tectonic evolution, and crustal deformation in the Northern Andes and Caribbean region. It covers topics such as subduction, plate kinematics, foreland basin development, orogenic wedge advance, and seismicity. The research also explores the role of detrital zircon in understanding sedimentation patterns and provides insights into the geological history of the area.

Keywords

Andean Geodynamics; Caribbean Plate Boundary; Subduction; Tectonic Evolution; Crustal Deformation; Foreland Basin; Plate Kinematics; Orogenic Wedge; Seismicity; Detrital Zircon

Petroleum Basins of South America

1995-01-01
A. J. Tankard , R. Suárez Soruco , H. J. Welsink
A monumental collection on the geology of South American basins. Jointly published by AAPG, YPFB, and Academia Nacional de Ciencias de Bolivia, this volume offers 41 papers (800 pages), covering … A monumental collection on the geology of South American basins. Jointly published by AAPG, YPFB, and Academia Nacional de Ciencias de Bolivia, this volume offers 41 papers (800 pages), covering more basins in greater detail than any previous South American compilation. The publication is organized into five sections: Regional Setting (6 papers); Paleozoic Basins (7 papers); Mesozoic Rifts (7 papers); Andean Basins (8 papers); Northern South America (13 papers).

Formation of the Maturín Foreland Basin, eastern Venezuela: Thrust sheet loading or subduction dynamic topography

2003-09-16
María I. Jácome , Nick Kusznir , Felipe Audemard +1 more
The Maturín Basin in eastern Venezuela is considered a good example of a peripheral foreland basin. Earthquake and tomographic data indicate that eastern Venezuela is affected by the oblique subduction … The Maturín Basin in eastern Venezuela is considered a good example of a peripheral foreland basin. Earthquake and tomographic data indicate that eastern Venezuela is affected by the oblique subduction of the South American Plate underneath the Caribbean Plate. New forward flexural isostatic modeling of eastern Venezuela has been carried out in order to determine whether the Maturín Basin was generated purely by thrust sheet loading from the Serranía and Monagas Foreland Thrust Belts. A sequence of forward models from middle Miocene to Present was generated for 3 profiles across the Serranía del Interior Thrust Belt, the Monagas Foreland Thrust Belt, and the Maturín Foreland Basin. The predictions of these models are constrained using seismic reflection and well data. The flexural isostatic modeling shows that thrust sheet loading associated with the Serranía del Interior and Monagas Foreland thrust belts is insufficient to generate the observed subsidence within the Maturín Basin. Dynamic fluid flow modeling of subduction related dynamic topography of eastern Venezuela has been used to investigate the influence of South American Plate subduction on the generation of the accommodation space observed in the Maturín Basin. Fluid flow modeling of subduction related dynamic topography suggests that the subduction of the South American lithospheric mantle caused downward deflection of the South American crust affecting the Maturín Basin and the Serranía Thrust Belt. This modeling suggests that the Maturín Basin subsidence has two components: 55% related to thrust sheet loading and 45% driven by continental subduction.

Tectonostratigraphic Terranes and Tectonic Evolution of Mexico

1993-01-01
Richard L. Sedlock , Fernando Ortega‐Gutiérrez , R. C. Speed

Plate tectonics of the Laramide orogeny

1978-01-01
William R. Dickinson , W.S. Snyder

The Geology of North America—An Overview

1989-01-01
A. W. Bally , Allison R. Palmer
Abstract Summaries of the major features of the geology of North America and the adjacent oceanic regions are presented. Twenty chapters include concise reviews of current thinking about Precambrian basement, … Abstract Summaries of the major features of the geology of North America and the adjacent oceanic regions are presented. Twenty chapters include concise reviews of current thinking about Precambrian basement, Phanerozoic orogens, cratonic basins, passive-margin geology of the Atlantic and Gulf Coast regions, marine and terrestrial geology of the Caribbean region, marine geology of the North Atlantic and northeast Pacific oceans, Quaternary geology, hydrogeology, and economic geology. An excellent text for a graduate course or upper-level undergraduate course in regional geology. Includes tables of contents for the other volumes in this series. Extended selected references also available.
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Geochronology, geochemistry and tectonic evolution of the Western and Central cordilleras of Colombia

2011-05-21
Diego Villagómez , Richard Spikings , Tomáš Magna +3 more

The fluvial geochemistry and denudation rate of the Guayana Shield in Venezuela, Colombia, and Brazil

1995-08-01
John M. Edmond , Martin R. Palmer , C. I. Measures +2 more

Plate Tectonic Model for the Evolution of the Central Andes

1971-01-01
David E. James
Research Article| December 01, 1971 Plate Tectonic Model for the Evolution of the Central Andes DAVID E JAMES DAVID E JAMES Carnegie Institution of Washington, Department of Terrestrial Magnetism, Washington, … Research Article| December 01, 1971 Plate Tectonic Model for the Evolution of the Central Andes DAVID E JAMES DAVID E JAMES Carnegie Institution of Washington, Department of Terrestrial Magnetism, Washington, D. C. 20015 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1971) 82 (12): 3325–3346. https://doi.org/10.1130/0016-7606(1971)82[3325:PTMFTE]2.0.CO;2 Article history received: 26 Apr 1971 rev-recd: 08 Jul 1971 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation DAVID E JAMES; Plate Tectonic Model for the Evolution of the Central Andes. GSA Bulletin 1971;; 82 (12): 3325–3346. doi: https://doi.org/10.1130/0016-7606(1971)82[3325:PTMFTE]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Data on the geophysics and geology of the central Andes are interpreted in terms of plate theory and a model for Andean evolution is presented. Analysis of upper mantle structure and seismicity shows that the underthrusting Pacific plate is now about 50 km thick and the overriding South American plate 200 to 300 km thick. Underthrusting of the Pacific plate probably began in Triassic time and has continued without substantial change to the present. Prior to underthrusting, the west coast of South America was quiescent, and great thicknesses of Paleozoic continental shelf deposits were laid down in an area east of the present volcanic arc. In Late Triassic or Early Jurassic time, an incipient arc began to form at or west of the present coast of South America. Igneous activity has since migrated eastward, culminating in the Pliocene-Pleistocene volcanic episode. The crust beneath the volcanic cordillera is more than 70 km thick and probably consists largely of rocks compositionally equivalent to those of the volcano-plutonic suites observed at the surface.Increase in crustal volume of the volcanic arc between Cretaceous time and the present implies either that the mantle above the under-thrust plate has undergone 18 to 36 percent partial melting or that 1 to 2 km of rock has been melted from the underthrusting plate. The intrusion of melt into the crust beneath the volcanic cordillera and the resultant crustal dilatation produced continentward compression of the Paleozoic sedimentary rocks which form an easterly belt of thrust and fold mountains. Here crustal shortening has produced crustal thicknesses of 50 to 55 km. Few deposits of the type normally termed eugeosynclinal, and no ophiolites, are observed between trench and volcanic arc; only in the intermontane foredeep behind the arc has a clastic wedge of geosynclinal proportions formed. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Wide plate margin deformation, southern Central America and northwestern South America, CASA GPS observations

2002-06-01
R. Trenkamp , James N. Kellogg , J. T. Freymueller +1 more

Anatomy and global context of the Andes: Main geologic features and the Andean orogenic cycle

2009-01-01
Víctor A. Ramos
The Andes make up the largest orogenic system developed by subduction of oceanic crust along a continental margin. Subduction began soon after the breakup of Rodinia in Late Proterozoic times, … The Andes make up the largest orogenic system developed by subduction of oceanic crust along a continental margin. Subduction began soon after the breakup of Rodinia in Late Proterozoic times, and since that time, it has been intermittently active up to the present. The evolution of the Pacific margin of South America during the Paleozoic occurred in the following stages: (1) initial Proterozoic rifting followed by subduction and final re-amalgamation of the margin in Early Cambrian times, as depicted by the Puncoviscana and Tucavaca Basins and related granitoids in southern Bolivia and northern Argentina; (2) a later phase of rifting...

Tectonics of the Caribbean and Middle America Regions from Focal Mechanisms and Seismicity

1969-01-01
Péter Molnár , Lynn R. Sykes
Seismic data strongly support recent theories of tectonics in which large plates of lithosphere move coherently with respect to one another as nearly rigid bodies, spreading apart at ocean ridges, … Seismic data strongly support recent theories of tectonics in which large plates of lithosphere move coherently with respect to one another as nearly rigid bodies, spreading apart at ocean ridges, sliding past one another at transform faults, and underthrusting at island arcs. Boundaries between adjacent plates of lithosphere are defined by belts of high seismic activity. Redetermination of more than 600 hypocenters in the Middle America region and previous studies in the Galapagos and Caribbean regions define the boundaries of two relatively small, nearly aseismic plates in the region of interest. The first, the Cocos plate, is bordered by the East Pacific rise, the Galapagos rift zone, the north-trending Panama fracture zone near 82° W., and the Middle America arc; the second, the Caribbean plate, underlies the Caribbean Sea and is bounded by the Middle America arc, the Cayman trough, the West Indies arc, and the seismic zone through northern South America. Focal mechanisms of 70 earthquakes in these regions were determined to ascertain the relative motion of these two plates with respect to the surrounding regions or plates. The results show underthrusting of the Cocos plate beneath Mexico and Guatemala in a northeasterly direction and beneath the rest of Central America in a more north-northeasterly direction. The Cocos plate is spreading away from the rest of the Pacific floor at the East Pacific rise and at the Galapagos rift zone. Motion is right-lateral strike-slip along the Panama fracture zone, a transform fault connecting the Galapagos rift zone and the Middle America arc. At the same time, the Caribbean plate is moving easterly with respect to the Americas plate, which is here taken to include both North and South America and the western Atlantic. Left-lateral strike-slip motion along steeply dipping fault planes is observed on the Cayman trough. The Americas plate is underthrusting the Caribbean in a westerly direction at the Lesser Antilles and near Puerto Rico. Unlike the Lesser Antilles, however, motion at present is not perpendicular to the Puerto Rico trench but instead is almost parallel to the trench along nearly horizontal fault planes. Computations of rates of motion indicate that underthrusting is at a higher rate in southeastern Mexico and Guatemala than in western Mexico and that the Caribbean is moving at a lower rate relative to North America than is the Cocos plate.

How Volcanoes Grow

1960-10-07
Jerry P. Eaton , K. J. Murata

Structure and tectonic history of the eastern Panama Basin

1978-01-01
Peter Lonsdale , Kim D. Klitgord
Research Article| July 01, 1978 Structure and tectonic history of the eastern Panama Basin PETER LONSDALE; PETER LONSDALE 1University of California, San Diego, Marine Physical Laboratory of the Scripps Institution … Research Article| July 01, 1978 Structure and tectonic history of the eastern Panama Basin PETER LONSDALE; PETER LONSDALE 1University of California, San Diego, Marine Physical Laboratory of the Scripps Institution of Oceanography, La Jolla, California 92093 Search for other works by this author on: GSW Google Scholar KIM D. KLITGORD KIM D. KLITGORD 2U.S. Geological Survey, Woods Hole, Massachusetts 02543 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1978) 89 (7): 981–999. https://doi.org/10.1130/0016-7606(1978)89<981:SATHOT>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation PETER LONSDALE, KIM D. KLITGORD; Structure and tectonic history of the eastern Panama Basin. GSA Bulletin 1978;; 89 (7): 981–999. doi: https://doi.org/10.1130/0016-7606(1978)89<981:SATHOT>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract New marine geophysical data allow the preparation of revised bathymetric and magnetic anomaly charts of the Panama Basin and demonstrate that the eastern part of the basin, between the fracture zone at long 83°W and the Colombian continental margin, was formed by highly asymmetric sea-floor spreading along the boundary of the Nazca and Cocos plates 27 to 8 m.y. B.P. Lineated magnetic anomalies recording this history are oriented approximately east-west. The oldest set of north-flank anomalies overlaps in age with those adjacent to the Grijalva scarp, south of the western Panama Basin, where they are oriented 065°. Younger anomalies (5C to 5) in the eastern basin are approximately parallel to anomalies of this age identified on the Carnegie platform and the flanks of the Costa Rica rift. The eastern basin now contains a pattern of fossil spreading centers (including the Malpelo rift) and transform faults (including the Yaquina graben) that were abandoned 8 m.y. B.P. by a shift in plate boundaries that transferred a large section of the Cocos plate to the Nazca plate. Cessation of Nazca-Cocos spreading east of long 83°W was heralded by a 3-m.y. deceleration of spreading on the eastern segments, which created rough topography and axial rift valleys typical of slow-spreading ridges. Westward jumping of the Nazca-Cocos-Caribbean triple junction rejuvenated the northern segment of the fracture zone at long 83°W, causing uplift of the adjacent Coiba Ridge. Recently, active transform faulting has jumped farther west, from the foot of the Coiba Ridge to the Panama fracture zone.Apart from changes in plate boundaries, the main event in the tectonic evolution of the region was initiation about 22 to 20 m.y. B.P. of the hot spot that created the Malpelo, Cocos, and Carnegie Ridges. Precursors of effusive ridge-building volcanism included major fracturing of the oceanic crust to the north of the present Malpelo Ridge. Both processes hamper identification of magnetic anomalies in the vicinity of the ridges. Our interpretation of the tectonic history is also incomplete in the easternmost parts of the basin, where data are insufficient; this impairs our interpretation of the adjacent continental geology in terms of changing interaction between oceanic and continental plates. The geologic history of the Isthmus of Panama is compatible with our application of the plate-tectonic model. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

A plate-kinematic framework for models of Caribbean evolution

1988-12-01
James Pindell , S. C. Cande , Walter C. Pitman +4 more

Geodynamics of the northern Andes: Subductions and intracontinental deformation (Colombia)

2000-10-01
Alfredo Taboada , Luis Rivera , Andrés Fuenzalida +5 more
New regional seismological data acquired in Colombia during 1993 to 1996 and tectonic field data from the Eastern Cordillera (EC) permit a reexamination of the complex geodynamics of northwestern South … New regional seismological data acquired in Colombia during 1993 to 1996 and tectonic field data from the Eastern Cordillera (EC) permit a reexamination of the complex geodynamics of northwestern South America. The effect of the accretion of the Baudó‐Panama oceanic arc, which began 12 Myr ago, is highlighted in connection with mountain building in the EC. The Istmina and Ibagué faults in the south and the Santa Marta‐Bucaramanga fault to the northeast limit an E‐SE moving continental wedge. Progressive indentation of the wedge is absorbed along reverse faults located in the foothills of the Cordilleras (northward of 5°N) and transpressive deformation in the Santander Massif. Crustal seismicity in Colombia is accurately correlated with active faults showing neotectonic morphological evidences. Intermediate seismicity allows to identify a N‐NE trending subduction segment beneath the EC, which plunges toward the E‐SE. This subduction is interpreted as a remnant of the paleo‐Caribbean plateau (PCP) as suggested by geological and tomographic profiles. The PCP shows a low‐angle subduction northward of 5.2°N and is limited southward by a major E‐W transpressive shear zone. Normal oceanic subduction of the Nazca plate (NP) ends abruptly at the southern limit of the Baudó Range. Northward, the NP subducts beneath the Chocó block, overlapping the southern part of the PCP. Cenozoic shortening in the EC estimated from a balanced section is ∼120 km. Stress analysis of fault slip data in the EC (northward of 4°N), indicates an ∼E‐SE orientation of σ1 in agreement with the PCP subduction direction. Northward, near Bucaramanga, two stress solutions were observed: (1) a late Andean N80°E compression and (2) an early Andean NW‐SE compression.
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Pliocene closing of the Isthmus of Panama, based on biostratigraphic evidence from nearby Pacific Ocean and Caribbean Sea cores

1978-01-01
Lloyd D Keigwin
Research Article| October 01, 1978 Pliocene closing of the Isthmus of Panama, based on biostratigraphic evidence from nearby Pacific Ocean and Caribbean Sea cores Lloyd D. Keigwin, Jr. Lloyd D. … Research Article| October 01, 1978 Pliocene closing of the Isthmus of Panama, based on biostratigraphic evidence from nearby Pacific Ocean and Caribbean Sea cores Lloyd D. Keigwin, Jr. Lloyd D. Keigwin, Jr. 1Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 02881 Search for other works by this author on: GSW Google Scholar Author and Article Information Lloyd D. Keigwin, Jr. 1Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 02881 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1978) 6 (10): 630–634. https://doi.org/10.1130/0091-7613(1978)6<630:PCOTIO>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Lloyd D. Keigwin; Pliocene closing of the Isthmus of Panama, based on biostratigraphic evidence from nearby Pacific Ocean and Caribbean Sea cores. Geology 1978;; 6 (10): 630–634. doi: https://doi.org/10.1130/0091-7613(1978)6<630:PCOTIO>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Pliocene and Pleistocene planktonic foraminiferal biogeography and paleoceanography have been examined in Deep Sea Drilling Project (DSDP) sites of the Panama Basin (Pacific Ocean) and Colombian and Venezuelan Basins (Atlantic Ocean) to determine the timing of the isolation of Atlantic and Pacific tropical planktonic faunas resulting from the development of the Central American isthmus. Previous studies have suggested a late Miocene to middle Pliocene occurrence of this event. The Panama Basin (DSDP site 157) and the Colombian Basin (DSDP site 154A) share two early Pliocene biogeographic events: (1) great abundance of sinistral coiling Neogloboquadrina pachyderma at 4.3 m.y. ago at site 157 and 0.7 m.y. later at site 154A, and (2) a sinistral-to-dextral change in the coiling-direction preference in Pulleniatina 3.5 m.y. ago at both locations. Identification of these events farther to the east in the Venezuelan Basin (DSDP site 148) is complicated by insufficient lower Pliocene core recovery, but abundant sinistral N. pachydcrma appear to have extended far to the east in the Caribbean 3.6 m.y. ago; perhaps the early Pliocene abundance of this form is not indicative of cool water.The coiling-direction history and stratigraphic ranges of Pulleniatina became different in the Atlantic and Pacific Oceans during the early Pliocene; this is inferred to result from geographic isolation of the assemblages. Saito (1976) used the temporary disappearance of this genus from Atlantic waters at 3.5 m.y. ago to mark the closure of the Isthmus of Panama, but I show that in the Colombian Basin (site 154A) its disappearance was closer to 3.1 m.y. ago. This suggests the possibility of surface-water communication between the Atlantic and Pacific until that time. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Chemistry of submarine hydrothermal solutions at Guaymas Basin, Gulf of California

1985-11-01
K. L. Von Damm , John M. Edmond , C. I. Measures +1 more

A crustal section across the Puerto Rico trench

1959-10-01
Manik Talwani , George H. Sutton , J. Lamar Worzel

Andean flat-slab subduction through time

2009-01-01
Víctor A. Ramos , Andrés Folguera
Abstract The analysis of magmatic distribution, basin formation, tectonic evolution and structural styles of different segments of the Andes shows that most of the Andes have experienced a stage of … Abstract The analysis of magmatic distribution, basin formation, tectonic evolution and structural styles of different segments of the Andes shows that most of the Andes have experienced a stage of flat subduction. Evidence is presented here for a wide range of regions throughout the Andes, including the three present flat-slab segments (Pampean, Peruvian, Bucaramanga), three incipient flat-slab segments (‘Carnegie’, Guañacos, ‘Tehuantepec’), three older and no longer active Cenozoic flat-slab segments (Altiplano, Puna, Payenia), and an inferred Palaeozoic flat-slab segment (Early Permian ‘San Rafael’). Based on the present characteristics of the Pampean flat slab, combined with the Peruvian and Bucaramanga segments, a pattern of geological processes can be attributed to slab shallowing and steepening. This pattern permits recognition of other older Cenozoic subhorizontal subduction zones throughout the Andes. Based on crustal thickness, two different settings of slab steepening are proposed. Slab steepening under thick crust leads to delamination, basaltic underplating, lower crustal melting, extension and widespread rhyolitic volcanism, as seen in the caldera formation and huge ignimbritic fields of the Altiplano and Puna segments. On the other hand, when steepening affects thin crust, extension and extensive within-plate basaltic flows reach the surface, forming large volcanic provinces, such as Payenia in the southern Andes. This last case has very limited crustal melt along the axial part of the Andean roots, which shows incipient delamination. Based on these cases, a Palaeozoic flat slab is proposed with its subsequent steepening and widespread rhyolitic volcanism. The geological evolution of the Andes indicates that shallowing and steepening of the subduction zone are thus frequent processes which can be recognized throughout the entire system.

Subduction of the Eastern Panama Basin and seismotectonics of northwestern South America

1981-11-10
Wayne D. Pennington
Spreading along the Cocos‐Nazca plate boundary since the breakup of the Farallon plate in the Miocene has resulted in the formation of the Panama basin and a complex interaction of … Spreading along the Cocos‐Nazca plate boundary since the breakup of the Farallon plate in the Miocene has resulted in the formation of the Panama basin and a complex interaction of plates in and near northwestern South America. Current plate boundaries have been defined, and segments of subducted lithosphere identified through selection of hypocentral locations of earthquakes, considering only well‐located events, and through focal mechanism determinations. The existence of relict plate boundaries, bathymetric features, and the Panamanian isthmus has affected the subduction process of the Nazca plate beneath South America and determined the present‐day configuration of the subducting lithospheric plate. There is no single triple junction separating the Caribbean, South American, and Nazca plates. Instead, the Panamanian isthmus and surrounding areas are accommodating east‐west compression (and a lesser degree of north‐south compression) along a series of thrust faults striking NW to NE, and the Andean ranges of Ecuador, Colombia, and Venezeula are moving as a block NNE relative to the rest of the South American plates, along a system of faults following the front of the Eastern Cordillera. The subducted portions of the Panama basin and old Farallon plate have become segmented into three pieces recognized in this study. From north to south, they are (1) a ‘Bucaramanga’ segment continuous with the Caribbean seafloor northwest of Colombia, (2) a ‘Cauca’ segment continuous with oceanic crust (Nazca plate) currently being subducted beneath South America at the Colombia‐Ecuador trench, and (3) an ‘Ecuador’ segment at the northern end of the subducted lithospheric plate which is dipping at a small angle to the east beneath northern Peru. The segmentation of the subducted plate can be explained by the buoyancy of bathymetric features which have been partially subducted.
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Andean tectonics related to geometry of subducted Nazca plate

1983-01-01
Teresa E. Jordan , Bryan L. Isacks , Richard W. Allmendinger +3 more
Research Article| March 01, 1983 Andean tectonics related to geometry of subducted Nazca plate TERESA E. JORDAN; TERESA E. JORDAN 1Department of Geological Sciences, Cornell University, Ithaca, New York 14853 … Research Article| March 01, 1983 Andean tectonics related to geometry of subducted Nazca plate TERESA E. JORDAN; TERESA E. JORDAN 1Department of Geological Sciences, Cornell University, Ithaca, New York 14853 Search for other works by this author on: GSW Google Scholar BRYAN L. ISACKS; BRYAN L. ISACKS 1Department of Geological Sciences, Cornell University, Ithaca, New York 14853 Search for other works by this author on: GSW Google Scholar RICHARD W. ALLMENDINGER; RICHARD W. ALLMENDINGER 1Department of Geological Sciences, Cornell University, Ithaca, New York 14853 Search for other works by this author on: GSW Google Scholar JON A. BREWER; JON A. BREWER 1Department of Geological Sciences, Cornell University, Ithaca, New York 148533Present addresses: (Brewer) Department of Earth Sciences. Maddingley Road, Cambridge CB3 OEZ. England; (Ando) Shell Development Company, P.O. Box 481. Houston, Texas 77001. Search for other works by this author on: GSW Google Scholar VICTOR A. RAMOS; VICTOR A. RAMOS 2Servicio Geologico National, Buenos Aires, Argentina Search for other works by this author on: GSW Google Scholar CLIFFORD J. ANDO CLIFFORD J. ANDO 1Department of Geological Sciences, Cornell University, Ithaca, New York 148533Present addresses: (Brewer) Department of Earth Sciences. Maddingley Road, Cambridge CB3 OEZ. England; (Ando) Shell Development Company, P.O. Box 481. Houston, Texas 77001. Search for other works by this author on: GSW Google Scholar Author and Article Information TERESA E. JORDAN 1Department of Geological Sciences, Cornell University, Ithaca, New York 14853 BRYAN L. ISACKS 1Department of Geological Sciences, Cornell University, Ithaca, New York 14853 RICHARD W. ALLMENDINGER 1Department of Geological Sciences, Cornell University, Ithaca, New York 14853 JON A. BREWER 1Department of Geological Sciences, Cornell University, Ithaca, New York 148533Present addresses: (Brewer) Department of Earth Sciences. Maddingley Road, Cambridge CB3 OEZ. England; (Ando) Shell Development Company, P.O. Box 481. Houston, Texas 77001. VICTOR A. RAMOS 2Servicio Geologico National, Buenos Aires, Argentina CLIFFORD J. ANDO 1Department of Geological Sciences, Cornell University, Ithaca, New York 148533Present addresses: (Brewer) Department of Earth Sciences. Maddingley Road, Cambridge CB3 OEZ. England; (Ando) Shell Development Company, P.O. Box 481. Houston, Texas 77001. Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1983) 94 (3): 341–361. https://doi.org/10.1130/0016-7606(1983)94<341:ATRTGO>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation TERESA E. JORDAN, BRYAN L. ISACKS, RICHARD W. ALLMENDINGER, JON A. BREWER, VICTOR A. RAMOS, CLIFFORD J. ANDO; Andean tectonics related to geometry of subducted Nazca plate. GSA Bulletin 1983;; 94 (3): 341–361. doi: https://doi.org/10.1130/0016-7606(1983)94<341:ATRTGO>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Seismological and geological data show that tectonic segmentation of the Andes coincides with segmentation of the subducted Nazca plate, which has nearly horizontal segments and 30° east-dipping segments. Andean tectonics above a flat-subducting segment between 28°S to 33°S are characterized by (from west to east): (1) a steady topographic rise from the coast to the crest of the Andes; (2) no significant Quaternary, and possibly Neogene, magmatism; (3) a narrow belt of eastward-migrating, apparently thin-skinned, Neogene to Quaternary shortening of the Andes; and (4) Plio-Pleistocene uplift of the crystalline basement on reverse faults in the Pampeanas Ranges. From about 15° to 24°S, over a 30°-dipping subducted plate, a west to east Andes cross section includes: (1) a longitudinal valley east of coastal mountains; (2) an active Neogene and Holocene andesitic volcanic axis; (3) the Altiplano-Puna high plateau; (4) a high Neogene but inactive thrust belt (Eastern Cordillera); and (5) an active eastward-migrating Subandean thin-skinned thrust belt. Tectonics above a steeply subducting segment south of 33°S are similar west of the volcanic axis, but quite different to the east.Early Cenozoic tectonics of western North America were quite similar to the Neogene Andes. However, duration of segmentation was longer and the width of deformation was greater in the western United States.Patterns of crustal seismicity are systematically related to Plio-Quaternary structural provinces, implying that current deformational processes have persisted since at least the Pliocene. Horizontal compression parallel to the plate convergence direction is indicated to a distance of 800 km from the trench. Above flat-subducting segments, crustal seismicity occurs over a broad region, whereas over steep segments, it is confined to the narrow thrust belt. Strain patterns in the forearc region are complex and perhaps extensional, and a broad region of the Altiplano-Puna and Eastern Cordillera appears to be aseismic. 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Marine incursions and the influence of Andean tectonics on the Miocene depositional history of northwestern Amazonia: results of a palynostratigraphic study

1993-11-01
Carina Hoorn

Neogene stratigraphy, paleoceanography and paleobiogeography in northwest South America and the evolution of the Panama seaway

1990-04-01
Hermann Duque-Caro

A hierarchical tectonic model of the Gulf of Mexico and Caribbean region

1988-12-01
Malcolm I. Ross , Christopher R. Scotese

Active Andean volcanism: its geologic and tectonic setting

2004-12-01
Charles R. Stern
El arco volcanico andino incluye mas de 200 estratovolcanes y, al menos, 12 sistemas de calderas gigantes potencialmente activos, dispuestos en cuatro segmentos separados de la cadena andina conocidos como … El arco volcanico andino incluye mas de 200 estratovolcanes y, al menos, 12 sistemas de calderas gigantes potencialmente activos, dispuestos en cuatro segmentos separados de la cadena andina conocidos como Zonas Volcanicas Norte, Central, Sur y Austral, y cuya actividad es producto de la subduccion de las placas oceanicas Nazca y Antartica bajo la placa sudamericana. Los cuatro segmentos con volcanismo activo ocurren en zonas donde el angulo de subduccion es relativamente inclinado (25°), y entre ellos existen regiones donde el angulo de subduccion es relativamente plano (<10°) a profundidades 100 km y el volcanismo esta ausente. Las zonas de bajo angulo de subduccion habrian comenzado a formarse durante el Mioceno debido a la subduccion de plateaus y dorsales oceanicas, indicando que la actual segmentacion de la zona de subduccion y el volcanismo andino es un rasgo transitorio relacionado a la actividad tectonica neogena. La relacion genetica entre subduccion y volcanismo ha sido confirmada por estudios geoquimicos que indican que la actividad magmatica se inicia por la deshidratacion y/o fusion de la litosfera oceanica subductada y la interaccion de los fluidos liberados con el manto astenosferico que la sobreyace. Componentes derivados de la corteza continental son tambien incorporados en los magmas andinos a traves de la erosion por subduccion del margen continental y/o asimilacion de material cortical en los magmas derivados del manto. Las variaciones en la tasa de erosion por subduccion y subduccion de corteza continental afectan en forma significativa no solo la quimica de los magmas andinos, sino tambien el acomplamiento mecanico de intraplaca en la zona de subduccion y la dinamica orogenica a lo largo de los Andes. Componentes corticales son mas significativos en los magmas extruidos en la Zona Volcanica Central donde la corteza es extremadamente gruesa (70 km) y las tasas de erosion por subduccion del margen continental alcanzan, posiblemente, a consumir un volumen de rocas equivalente hasta un 4% del volumen de la corteza oceanica subductada, son tambien muy elevadas debido a las condiciones climaticas hiperaridas y el bajo aporte de sedimentos a la fosa. Lavas, flujos piroclasticos, lahares, flujos de detritos producto de colapso sectorial de estratovolcanes, y la caida de tefra son algunos de los peligros y riesgos mas importantes asociados al volcanismo andino. Desde el ano 1532 mas de 25.000 personas han muerto como consecuencia de 600 erupciones con registro historico. La mayor parte de estas muertes ocurrio en 1985 durante la erupcion de los Nevados del Ruiz en Colombia. A pesar de que mas de 20 millones de personas viven a menos de 100 km de distancia de un volcan activo en los Andes, principalmente en los valles interandinos de Colombia y Ecuador y el Valle Central del centro-sur de Chile, en la actualidad, menos de 25 volcanes estan siendo monitoreados para determinar los riesgos potenciales asociados a la actividad volcanica andina.
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Alleghenian reconstruction and subsequent evolution of the Gulf of Mexico, Bahamas, and Proto‐Caribbean

1985-01-01
James Pindell
A detailed model for the evolution of the Gulf of Mexico, the Bahamas and the Proto‐Caribbean is built within the framework provided by a detailed initial Alleghenian (western Pangean) reconstruction … A detailed model for the evolution of the Gulf of Mexico, the Bahamas and the Proto‐Caribbean is built within the framework provided by a detailed initial Alleghenian (western Pangean) reconstruction and an accurate subsequent relative‐motion history between North America and Gondwana (northern Africa and South America). The Alleghenian reconstruction closes all pre‐Jurassic oceans; accounts for Jurassic attenuation of continental crust by restoring that attenuation to original prerift continental thicknesses; incorporates an improved Equatorial Atlantic fit between northern Brazil and the Guinea margin of Africa; quantitatively removes changes in shape of northern South America due to Late Cretaceous and Cenozoic accretion and internal deformation; includes pre‐Mesozoic continental crust presently underlying the western Bahamas and southern Florida; and correlates Late Paleozoic geology of Yucatan with its neighboring continental masses. Extension occurred within the Gulf of Mexico from Late Triassic to earliest Cretaceous time, but seafloor spreading was delayed until the Late Callovian. This divided a single Gulf‐wide salt basin into the Louann and Campeche salt provinces. The Yucatan block progressively rotated about 43 degrees counterclockwise away from the Texas‐Louisiana margin around a pole in northern Florida. The Tamaulipas‐Golden Lane‐Chiapas fault zone of eastern Mexico is interpreted as the remains of an initially intracontinental transform system along which Yucatan migrated. Attenuated continental crust beneath southern Florida and the western Bahamas, termed here the Florida Straits block, migrated approximately 300 km out of the eastern Gulf, approximately along Central Atlantic flow lines. These rotations are consistent with recently suggested magnetic anomaly trends in the Gulf of Mexico (Shepherd et al., 1982; S. Hall, personal communication, 1984). The Proto‐Caribbean formed synchronously by a fan‐like rotation of Yucatan away from Venezuela.

Evidence for middle Eocene and younger land emergence in central Panama: Implications for Isthmus closure

2012-01-13
Camilo Montes , A. Cardona , Rory R. McFadden +7 more
Research Article| May 01, 2012 Evidence for middle Eocene and younger land emergence in central Panama: Implications for Isthmus closure Camilo Montes; Camilo Montes † 1Smithsonian Tropical Research Institute, Box … Research Article| May 01, 2012 Evidence for middle Eocene and younger land emergence in central Panama: Implications for Isthmus closure Camilo Montes; Camilo Montes † 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá2Geociencias, Universidad de los Andes, Calle 1A # 18A-10, Edificio IP, Bogotá DC, Colombia †E-mail: [email protected] Search for other works by this author on: GSW Google Scholar A. Cardona; A. Cardona 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá3Ingenieria de Petroleos, Universidad Nacional de Colombia, Carrera 80 No. 65-223, Medellín, Colombia Search for other works by this author on: GSW Google Scholar R. McFadden; R. McFadden 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar S.E. Morón; S.E. Morón 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar C.A. Silva; C.A. Silva 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar S. Restrepo-Moreno; S. Restrepo-Moreno 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá4Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, 24 Florida 32611, USA Search for other works by this author on: GSW Google Scholar D.A. Ramírez; D.A. Ramírez 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar N. Hoyos; N. Hoyos 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar J. Wilson; J. Wilson 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar D. Farris; D. Farris 5Department of Earth, Ocean and Atmospheric Science, Florida State University, 1017 26 Academic Way, Tallahassee, Florida 32306-4520, USA Search for other works by this author on: GSW Google Scholar G.A. Bayona; G.A. Bayona 6Corporación Geológica Ares, Calle 44A # 53-96, Bogotá, Colombia Search for other works by this author on: GSW Google Scholar C.A. Jaramillo; C.A. Jaramillo 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar V. Valencia; V. Valencia 7Department of Geosciences, University of Arizona, Gould-Simpson Building #77, 1040 E Street, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar J. Bryan; J. Bryan 8Geology/Oceanography, Northwest Florida State College, 100 College Boulevard, Niceville, Florida 32578, USA Search for other works by this author on: GSW Google Scholar J.A. Flores J.A. Flores 9Facultad de Ciencias, Departamento de Geología, Universidad de Salamanca, 37008 Salamanca, Spain Search for other works by this author on: GSW Google Scholar GSA Bulletin (2012) 124 (5-6): 780–799. https://doi.org/10.1130/B30528.1 Article history received: 07 Apr 2011 rev-recd: 01 Oct 2011 accepted: 19 Oct 2011 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Camilo Montes, A. Cardona, R. McFadden, S.E. Morón, C.A. Silva, S. Restrepo-Moreno, D.A. Ramírez, N. Hoyos, J. Wilson, D. Farris, G.A. Bayona, C.A. Jaramillo, V. Valencia, J. Bryan, J.A. Flores; Evidence for middle Eocene and younger land emergence in central Panama: Implications for Isthmus closure. GSA Bulletin 2012;; 124 (5-6): 780–799. doi: https://doi.org/10.1130/B30528.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The rise of the Isthmus of Panama, linked to a number of climatic, paleoceanographic, and biological events, has been studied mostly from indirect, often distal, geochemical and biotic evidence. We have upgraded existing geologic mapping in central Panama with more than 2000 field stations, over 40 petrographic analyses, and more than 30 new geochronological and thermochronological analyses. This data set suggests that the isthmus was an uninterrupted chain above sea level from late Eocene until at least late Miocene times. The basement complex of central Panama is a folded-faulted, ∼3-km-thick arc sequence, intruded by granitoid bodies and onlapped by mildly deformed upper Eocene and Oligocene strata. Six U/Pb zircon ages in the granitoids—along with published geochronological data—reveal intense late Paleocene to middle Eocene magmatism (58–39 Ma), a temporary cessation of magmatic activity between 38 and 27 Ma, and renewed magmatism between 25 and 15 Ma in a position ∼75 km south of the former magmatic axis. Thermochronological analyses in zircon (eight U-Th/He ages), and in apatite crystals (four U-Th/He ages and nine fission-track ages) obtained from a subset of 58–54 Ma granitoid bodies record a concordant Lutetian-age (47–42 Ma) cooling from ∼200 °C to ∼70 °C in ∼5 m.y., and cooling below ∼40 °C between 12 and 9 Ma. Cooling is linked to exhumation by an angular unconformity that separates the deformed basement complex below from mildly deformed, upper Eocene to Oligocene terrestrial to shallow-marine strata above. Exhumation and erosion of the basement complex are independently confirmed by lower Miocene strata that have a detrital zircon signature that closely follows the central Panama basement complex age distribution. These results greatly restrict the width and depth of the strait separating southern Central America from South America, and challenge the widely accepted notion that the Central American Seaway closed in late Pliocene time, when the ice age began. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate: Reply

1973-01-01
BRUCE T. MALFAIT , M. G. Dinkelman
Research Article| March 01, 1973 Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate: Reply BRUCE T. MALFAIT; BRUCE T. MALFAIT 1School of Oceanography, Oregon State University, … Research Article| March 01, 1973 Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate: Reply BRUCE T. MALFAIT; BRUCE T. MALFAIT 1School of Oceanography, Oregon State University, Corvallis, Oregon 97331 Search for other works by this author on: GSW Google Scholar MENNO G. DINKELMAN MENNO G. DINKELMAN 1School of Oceanography, Oregon State University, Corvallis, Oregon 97331 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1973) 84 (3): 1105–1108. https://doi.org/10.1130/0016-7606(1973)84<1105:CTAIAA>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation BRUCE T. MALFAIT, MENNO G. DINKELMAN; Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate: Reply. GSA Bulletin 1973;; 84 (3): 1105–1108. doi: https://doi.org/10.1130/0016-7606(1973)84<1105:CTAIAA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract No Abstract Available. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Along-strike segmentation of the Andean foreland: causes and consequences

1999-01-01
Jonas Kley , César R. Monaldi , José A. Salfity

The evolution of Middle America and the Gulf of Mexico–Caribbean Sea region during Mesozoic time

1983-01-01
Thomas H. Anderson , Victor A. Schmidt
Research Article| August 01, 1983 The evolution of Middle America and the Gulf of Mexico–Caribbean Sea region during Mesozoic time THOMAS H. ANDERSON; THOMAS H. ANDERSON 1Department of Geology and … Research Article| August 01, 1983 The evolution of Middle America and the Gulf of Mexico–Caribbean Sea region during Mesozoic time THOMAS H. ANDERSON; THOMAS H. ANDERSON 1Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, Pennsylvania Search for other works by this author on: GSW Google Scholar VICTOR A. SCHMIDT VICTOR A. SCHMIDT 1Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, Pennsylvania Search for other works by this author on: GSW Google Scholar GSA Bulletin (1983) 94 (8): 941–966. https://doi.org/10.1130/0016-7606(1983)94<941:TEOMAA>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation THOMAS H. ANDERSON, VICTOR A. SCHMIDT; The evolution of Middle America and the Gulf of Mexico–Caribbean Sea region during Mesozoic time. GSA Bulletin 1983;; 94 (8): 941–966. doi: https://doi.org/10.1130/0016-7606(1983)94<941:TEOMAA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A plate-tectonic model for the evolution of Middle America and the Gulf of Mexico-Caribbean Sea region is presented. The model, which is based upon the existence of the Mojave-Sonora megashear, incorporates into the Triassic Pangea reconstruction three microplates between North and South America, thus avoiding the overlap of the Bullard fit. These plates are the Yaqui, bounded on the north by the Mojave-Sonora megashear; the east and west Maya plates, bounded on the north by the Mexican volcanic zone and on the south by a predecessor of the Motagua fault zone; and the Chortis plate (parts of Guatemala and Honduras). During Late Jurassic time, as North America split away from Europe, Africa, and South America, shear, with left-lateral sense of displacement, occurred along the transform faults that bounded the micro-plates.If ∼800 km of left-lateral displacement along the Mojave-Sonora megashear, ∼300 km along the Mexican volcanic belt, and ∼1,300 km along a proto-Motagua megashear are restored, and if Yucatan and Cuba are rotated to fit against northern South America, then (1) a curvilinear belt of late Paleozoic rocks that show lithologic as well as paleontologic similarities extends across the reconstruction and links outcrops in Texas, eastern Mexico, nuclear Central America, and Colombia; (2) a Mediterranean-like sea is delineated that was a precursor of most of the present Gulf of Mexico; (3) correlation is implied between the distinctive quartzose San Cayetano Formation of Cuba and the Caracas and Juan Griego Groups of Venezuela.Geometric constraints suggest that probably shear initially occurred along the Mexican volcanic zone near the end of the Middle Jurassic. Subsequently, probably about 160 m.y. ago, displacements that total ∼800 km began along the Mojave-Sonora megashear. Contemporaneously, Yucatan and fragments of pre-Cretaceous rocks that compose parts of central and western Cuba migrated northward toward their present positions. Rotation of Yucatan was facilitated by considerable displacement along the proto-Motagua zone and along a zone that is probably coincident with the modern Salina Cruz fault. Accumulation of widespread major salt units of Late Jurassic (Callovian to early Oxfordian) age in the Gulf Basin probably occurred contemporaneously with the arrival of these blocks at their present positions. Clastic units that interfinger with some of the youngest salt units and rim the Gulf of Mexico have not recorded major recognized translations since their accumulation.Clockwise rotation of South America and the Chortis plate occurred during Early Cretaceous time. This movement, which was manifested by subduction of Jurassic ocean floor against the previously rifted precursor of the island of Cuba and under parts of Hispaniola and Puerto Rico, is recorded by circum-Caribbean orogeny.Abrupt changes in the relative motions between North and South America during Late Cretaceous time may have resulted in extension and outpourings of basalt upon the Jurassic rocks of the ocean floor of the Venezuelan Basin. West of Beata Ridge, sea-floor spreading formed the Colombian Basin. Related subduction occurred as the Chortis plate (including part of Central America, the Nicaraguan Rise, and southeastern Cuba) was sutured against the Maya East plate along the present Motagua fault and Cayman Trench.Our model is constrained by published geologic data, the relative positions of North and South America from Atlantic sea-floor magnetic anomalies, and the requirement that the major transform faults be compatible with the poles of rotation for the appropriate relative motions between North and South America. Paleomagnetic data from Middle America are sparse but do not conflict with the predicted motions of some of the microplates, especially Chortis. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Tectonic evolution of the Gulf of Mexico, Caribbean and northern South America in the mantle reference frame: an update

2009-01-01
James Pindell , Lorcan Kennan
Abstract We present an updated synthesis of the widely accepted ‘single-arc Pacific-origin’ and ‘Yucatán-rotation’ models for Caribbean and Gulf of Mexico evolution, respectively. Fourteen palaeogeographic maps through time integrate new … Abstract We present an updated synthesis of the widely accepted ‘single-arc Pacific-origin’ and ‘Yucatán-rotation’ models for Caribbean and Gulf of Mexico evolution, respectively. Fourteen palaeogeographic maps through time integrate new concepts and alterations to earlier models. Pre-Aptian maps are presented in a North American reference frame. Aptian and younger maps are presented in an Indo-Atlantic hot spot reference frame which demonstrates the surprising simplicity of Caribbean–American interaction. We use the Müller et al. ( Geology 21 : 275–278, 1993) reference frame because the motions of the Americas are smoothest in this reference frame, and because it does not differ significantly, at least since c. 90 Ma, from more recent ‘moving hot spot’ reference frames. The Caribbean oceanic lithosphere has moved little relative to the hot spots in the Cenozoic, but moved north at c. 50 km/Ma during the Cretaceous, while the American plates have drifted west much further and faster and thus are responsible for most Caribbean–American relative motion history. New or revised features of this model, generally driven by new data sets, include: (1) refined reconstruction of western Pangaea; (2) refined rotational motions of the Yucatán Block during the evolution of the Gulf of Mexico; (3) an origin for the Caribbean Arc that invokes Aptian conversion to a SW-dipping subduction zone of a trans-American plate boundary from Chortís to Ecuador that was part sinistral transform (northern Caribbean) and part pre-existing arc (eastern, southern Caribbean); (4) acknowledgement that the Caribbean basalt plateau may pertain to the palaeo-Galapagos hot spot, the occurrence of which was partly controlled by a Proto-Caribbean slab gap beneath the Caribbean Plate; (5) Campanian initiation of subduction at the Panama–Costa Rica Arc, although a sinistral transform boundary probably pre-dated subduction initiation here; (6) inception of a north-vergent crustal inversion zone along northern South America to account for Cenozoic convergence between the Americas ahead of the Caribbean Plate; (7) a fan-like, asymmetric rift opening model for the Grenada Basin, where the Margarita and Tobago footwall crustal slivers were exhumed from beneath the southeast Aves Ridge hanging wall; (8) an origin for the Early Cretaceous HP/LT metamorphism in the El Tambor units along the Motagua Fault Zone that relates to subduction of Farallon crust along western Mexico (and then translated along the trans-American plate boundary prior to onset of SW-dipping subduction beneath the Caribbean Arc) rather than to collision of Chortis with Southern Mexico; (9) Middle Miocene tectonic escape of Panamanian crustal slivers, followed by Late Miocene and Recent eastward movement of the ‘Panama Block’ that is faster than that of the Caribbean Plate, allowed by the inception of east–west trans-Costa Rica shear zones. The updated model integrates new concepts and global plate motion models in an internally consistent way, and can be used to test and guide more local research across the Gulf of Mexico, the Caribbean and northern South America. Using examples from the regional evolution, the processes of slab break off and flat slab subduction are assessed in relation to plate interactions in the hot spot reference frame.

Andean tectonics as a cause for changing drainage patterns in Miocene northern South America

1995-01-01
Carina Hoorn , Javier Guerrero , Gustavo Sarmiento +1 more
Research Article| March 01, 1995 Andean tectonics as a cause for changing drainage patterns in Miocene northern South America Carina Hoorn; Carina Hoorn 1Hugo de Vries-Laboratorium, Kruislaan 318, 1098 SM … Research Article| March 01, 1995 Andean tectonics as a cause for changing drainage patterns in Miocene northern South America Carina Hoorn; Carina Hoorn 1Hugo de Vries-Laboratorium, Kruislaan 318, 1098 SM Amsterdam, Netherlands Search for other works by this author on: GSW Google Scholar Javier Guerrero; Javier Guerrero 2Ingeominas, Diagonal 53 no. 34-53, Bogotá, Colombia Search for other works by this author on: GSW Google Scholar Gustavo A. Sarmiento; Gustavo A. Sarmiento 2Ingeominas, Diagonal 53 no. 34-53, Bogotá, Colombia Search for other works by this author on: GSW Google Scholar Maria A. Lorente Maria A. Lorente 3Maraven S. A., Apartado 829, Caracas 1010A, Venezuela Search for other works by this author on: GSW Google Scholar Geology (1995) 23 (3): 237–240. https://doi.org/10.1130/0091-7613(1995)023<0237:ATAACF>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Carina Hoorn, Javier Guerrero, Gustavo A. Sarmiento, Maria A. Lorente; Andean tectonics as a cause for changing drainage patterns in Miocene northern South America. Geology 1995;; 23 (3): 237–240. doi: https://doi.org/10.1130/0091-7613(1995)023<0237:ATAACF>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract New data from Neogene strata in northern South America suggest that Miocene tectonism in the northeastern Andes was responsible for the genesis of the Amazon River and changes in the drainage patterns of other major rivers such as the Magdalena and the Orinoco. Here we present a new model for the paleogeographic evolution of northern South America during the Miocene. In the early Miocene, a large part of the drainage of northwest Amazonia was directed northward along the paleo–Orinoco river system to a delta in Lake Maracaibo. Uplift of the Eastern Cordillera in the late middle Miocene caused the first development of the Amazon River; however, no connection with the Atlantic was established, and the Amazon fed the paleo–Orinoco river system, which drained toward the Caribbean. Substantial Andean uplift in the late Miocene resulted in major changes in paleogeography: the Orinoco changed its course, the Amazon established a connection to the Atlantic, causing the drowning of carbonate platforms, and the Amazon–Caribbean connection was closed. Thus the drainage and paleogeography of northern South America in the Miocene were strongly controlled by tectonic movements in the northeastern Andes. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Altiplano-Puna volcanic complex of the central Andes

1989-01-01
Shanaka L. de Silva
Research Article| December 01, 1989 Altiplano-Puna volcanic complex of the central Andes S. L. de Silva S. L. de Silva 1Lunar & Planetary Institute, 3303 NASA Road 1, Houston, Texas … Research Article| December 01, 1989 Altiplano-Puna volcanic complex of the central Andes S. L. de Silva S. L. de Silva 1Lunar & Planetary Institute, 3303 NASA Road 1, Houston, Texas 77058 Search for other works by this author on: GSW Google Scholar Geology (1989) 17 (12): 1102–1106. https://doi.org/10.1130/0091-7613(1989)017<1102:APVCOT>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation S. L. de Silva; Altiplano-Puna volcanic complex of the central Andes. Geology 1989;; 17 (12): 1102–1106. doi: https://doi.org/10.1130/0091-7613(1989)017<1102:APVCOT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Since the late Miocene an ignimbrite flare-up has resulted in a major volcano-tectonic province, the Altiplano-Puna volcanic complex, in the lat 21° to 24°S part of the Central Volcanic Zone of the Andes. The dominant elements of the complex, which defines an area of about 50000 km2 between the Atacama basin and the Altiplano, are several large nested caldera complexes which are the source structures for the major regionally distributed ignimbrite sheets that characterize the complex. The chemical and physical characteristics of these ignimbrites are best reconciled with an origin by large-scale crustal melting. The timing of the ignimbrite flare-up coincides well with thickening of the Central Volcanic Zone crust just prior to the late Miocene, and the coincidence of the Altiplano-Puna volcanic complex with the thickest part of this crust (∼70 km) points to a cause and effect relation. Crustal melting in response to crustal thickening and the heat input from subduction-related magmas is suggested to have resulted in large-scale sificic magmatism. Diapiric uprise of these magmas into a zone of tectonically weakened crust due to strike-slip tectonics associated with the Atacama basin resulted in major ignimbrite eruptions and the formation of the calderas of the Altiplano-Puna volcanic complex. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Basin Development and Tectonic History of the Llanos Basin, Eastern Cordillera, and Middle Magdalena Valley, Colombia

1995-01-01
M. A. Cooper , F. T. Addison , R. Alvarez +7 more
The Middle Magdalena Valley, Eastern Cordillera, and Llanos basin constituted a major regional sedimentary basin from the Triassic to the middle Miocene. Basin development began during the Triassic to the … The Middle Magdalena Valley, Eastern Cordillera, and Llanos basin constituted a major regional sedimentary basin from the Triassic to the middle Miocene. Basin development began during the Triassic to the earliest Cretaceous with a synrift megasequence related to the separation of North and South America in the proto-Caribbean. The synrift megasequence began with deposition in a continental environment that became paralic and shallow marine in the Early Cretaceous. Basin development continued into the Cretaceous in a back-arc setting east of the Andean subduction zone. The back-arc megasequence was dominated by shallow-marine sedimentation and produced an excellent regional source rock during the Turonian-Coniacian. Marine deposition was abruptly terminated during the ear y Maastrichtian due to the final accretion of the Western Cordillera. Accretion of the Western Cordillera created the early pre-Andean foreland basin megasequence of late Maastrichtian to early Eocene age. This depositional episode consists of coal-rich alluvial plain, coastal plain, and estuarine deposits throughout the Middle Magdalena Valley, Eastern Cordillera, and eastern Llanos basin. The megasequence was terminated by middle Eocene deformation in the Magdalena Valley, which ended sediment deposition throughout Colombia. Loading effects of this deformation reestablished the basin, in which the late pre-Andean foreland basin megasequence was deposited, until the early Miocene. This megasequence also consists of alluvial plain, coastal plain, and estuarine deposits, including the primary reservoir in the Llanos Foothills--the upper Eocene Mirador Fo mation. The megasequence also includes a series of four major grossly coarsening-upward cycles in the Llanos basin; these cycles correspond to changes in sea level, sediment supply, and foreland basin loading. The mudstone in the lowermost of these cycles is the regional seal in the Llanos basin and Foothills. The middle Miocene onset of Andean deformation in the Eastern Cordillera isolated the Middle Magdalena Valley from the Llanos basin. The deformation was dominated by inversion of the basin-controlling faults; the resultant loading of the lithosphere created the accommodation space for the Andean foreland basin megasequence. A major transgression into the Llanos basin coeval with this deformation caused deposition of marine mudstones in the lower part of the megasequence. However, the majority of the Andean foreland basin megasequence consists of the Guayabo Formation, a classic molasse sequence, deposited in a high-energy, coarse-grained, bed-load-dominated fluvial system that was supplied by the developing mountains of the Eastern Cordillera.

Tectonic Evolution of the Caribbean

1988-05-01
Kevin Burke
The development of the Caribbean is discussed in terms of modern tectonic theory. The nature of the site on which the Caribbean formed is examined, and the development of the … The development of the Caribbean is discussed in terms of modern tectonic theory. The nature of the site on which the Caribbean formed is examined, and the development of the rifted margins of the Caribbean is described. Constraints on Caribbean evolution from the relative motions of North and South America are briefly examined, and the Caribbean Oceanic Plateau is discussed. The great island-arc system of the Caribbean is addressed in detail, emphasizing the way the Great Arc of the Caribbean was segmented. The role of Central America in Caribbean history is briefly considered.

Plate reconstructions, aseismic ridges, and low-angle subduction beneath the Andes

1981-01-01
Rex H. Pilger
Research Article| July 01, 1981 Plate reconstructions, aseismic ridges, and low-angle subduction beneath the Andes REX H. PILGER, JR. REX H. PILGER, JR. 1Department of Geology, Louisiana State University, Baton … Research Article| July 01, 1981 Plate reconstructions, aseismic ridges, and low-angle subduction beneath the Andes REX H. PILGER, JR. REX H. PILGER, JR. 1Department of Geology, Louisiana State University, Baton Rouge, Louisiana 70803 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1981) 92 (7): 448–456. https://doi.org/10.1130/0016-7606(1981)92<448:PRARAL>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation REX H. PILGER; Plate reconstructions, aseismic ridges, and low-angle subduction beneath the Andes. GSA Bulletin 1981;; 92 (7): 448–456. doi: https://doi.org/10.1130/0016-7606(1981)92<448:PRARAL>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Low-angle—subduction segments beneath Peru and Chile are believed to represent interaction of the subduction zone with the aseismic Nazca and Juan Fernandez Ridges. On the basis of symmetric sea-floor–spreading models and plate-hotspot reconstructions, predicted continuations of the relatively buoyant ridges correspond well with the limits of the low-angle–subduction segments. Further, the history of interaction of the aseismic ridges with the subduction zone, as predicted by plate reconstructions, is not inconsistent with available information on volcanic episodes of the Andes, if the contemporary correlation of volcanic gaps and low-angle subduction is also applicable to the rest of the late Cenozoic.The occurrence of deep seismicity beneath the eastern flanks of the Andes is also believed to reflect the effects of low-angle subduction. The deep-seismic segments are adjacent to segments which are presently, or were recently, experiencing low-angle subduction. Thus, the deep seismicity is interpreted as representative of remnants of "normal" oceanic lithosphere subducted before interaction of aseismic ridges with the subduction zone.Other geologic phenomena are associated with low-angle subduction beneath South America, including landward shift in loci of tectonism, surficial subsidence, and Laramide-style deformation. The aseismic-ridge—buoyancy hypothesis appears to be a valuable predictive tool for the interpretation of such geologic effects. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Meso-Cenozoic Caribbean Paleogeography: Implications for the Historical Biogeography of the Region

2006-09-01
Manuel A. Iturralde-Vinent
Since the latest Triassic, the Caribbean started to form as a system of rift valleys within westcentral Pangea, later evolving into a mediterranean sea where distinct volcanic and non-volcanic islands … Since the latest Triassic, the Caribbean started to form as a system of rift valleys within westcentral Pangea, later evolving into a mediterranean sea where distinct volcanic and non-volcanic islands evolved. Since its very early formation, this sea has been playing an important role controlling the historical patterns of ocean water circulation, moderating the world climate, and determining the possibilities of biotic exchange of the surrounding terrestrial and marine ecosystems. The formation of a Mesozoic marine seaway between western Tethys and the eastern Pacific, across west-central Pangea, has been postulated for the Early Jurassic (Hettangian-Pliensbachian) according to biogeographic considerations, but supporting stratigraphic data are lacking. Probably since the Bathonian but certainly since the Oxfordian, the stratigraphic record indicates that this connection was fully functional and the Circum-Tropical marine current was active. Overland dispersal between western Laurasia (North America) and western Gondwana (South America) was interrupted in the Callovian when the continents were separated by a marine gap. Later, a connecting land bridge may have been present during the latest Campanian/Maastrichtian (~75-65 Ma), and since the Plio-Pleistocene (2.5-2.3 Ma). Evidence for a precursor bridge late in the Middle Miocene is currently ambiguous. Since the formation of the first volcanic archipelago within the Caribbean realm at about the Jurassic-Cretaceous transition, volcanic islands, shallow banks, and ridges have been present in the paleogeographic evolution of the area. However, these lands were generally ephemeral, and lasted just a few million years. Only after the Middle Eocene (<40 Ma) were permanent lands present within the Caribbean realm, providing substrates for the formation and development of the present terrestrial biota.

Tectono-stratigraphic terranes and mineral resource distributions in Mexico

1983-06-01
Maria Fernanda Campa , Peter J. Coney
About 80% of the southern part of the North American Cordillera within the Republic of Mexico is made up of suspect terranes. These terranes are suspect because their paleogeographic setting … About 80% of the southern part of the North American Cordillera within the Republic of Mexico is made up of suspect terranes. These terranes are suspect because their paleogeographic setting with respect to cratonic North America at various times through much of Phanerozoic time is uncertain. Much of northeastern and southeastern Mexico is underlain by basement accreted during late Paleozoic time, an extension of the Appalachian–Ouachita orogeny. This orogen has been considerably modified by Jurassic strike-slip translations related to the opening of the Gulf of Mexico. Western and southwestern Mexico is largely made up of several distinct but coeval latest Jurassic to Late Cretaceous submarine magmatic arc terranes with unknown basement that appear to have accreted against the disrupted North American margin by early Tertiary time. Only northeastern Sonora and the State of Chihuahua appear to be floored by unmoved North American cratonic basement. The combined effect of Mesozoic accretions and translations essentially eliminates the overlap of South America upon Mexico that is drived from late Paleozoic – early Mesozoic reconstructions of the closed Atlantic Ocean. This new vision of accretionary and translational tectonics in Mexico has profound implications for the study of tectogenesis in the southern Cordillera as well as for the interpretation of Mexico's vast natural resources. Preliminary analysis indicates that Mexico's gold–silver and lead–zinc deposits are directly or indirectly related to the terrane distributions discussed.

On the Functioning of the Southern Oscillation in the South American Sector. Part I: Surface Climate

1988-03-01
Patricio Aceituno
The functioning of the Southern Oscillation (SO) over South America and the surrounding tropical Atlantic and eastern Pacific Oceans is studied through analyses of bimonthly patterns of correlation between an … The functioning of the Southern Oscillation (SO) over South America and the surrounding tropical Atlantic and eastern Pacific Oceans is studied through analyses of bimonthly patterns of correlation between an SO index and the fields of pressure, wind, temperature and rainfall; hydrometeorological anomalies being further ascertained from river discharge and lake level records and measurements of outgoing longwave radiation. Most pronounced is the anomalously low pressure over the eastern Pacific during the negative SO phase (defined by anomalously low/high pressure at Tahiti/Darwin). Consistently positive SO-pressure correlations over the eastern tropical Pacific extend eastward into the North Atlantic region and southern South America during the respective winter semester. During the austral winter the tendency for anomalously abundant rainfall in central Chile during the negative SO phase appears related to an anomalously weak and northward displaced South Pacific subtropical high, while relatively dry conditions in the northwestern portion of the continent seem related to enhanced pressure in the Caribbean. During the austral summer, SO-related climate anomalies grow most pronounced, particularly conspicuous being the following three anomaly regimes of the negative SO phase: (i) The excessive rainfall along the Ecuador-Peru littoral and the adjacent open equatorial Pacific is consistent with an intensified and southward displaced new-equatorial trough; (ii) In the tropical North Atlantic during the latter past of the austral summer, the near-equatorial trough is displaced northward, the meridional pressure gradient is reduced, the northeast trades are weak, the surface waters are anomalously warm, and consistent with the large-scale circulation relatively dry conditions prevail in Northeast Brazil and part of the Amazon basin; (iii) Contrasting with concurrent negative rainfall anomalies in a large portion of tropical South America, a weak tendency for relatively wet conditions is apparent in the Paraná river basin. This feature, most pronounced in the early part of the austral summer, appears associated with intensified frontal activity.
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Evolution of the northern Gulf of Mexico, with emphasis on Cenozoic growth faulting and the role of salt

1989-01-01
Dan M. Worrall , S. Snelson
Abstract The northern Gulf of Mexico Basin, although one of the most intensely studied and explored regions in North America, is also one of the most structurally complex (Figs. 1 … Abstract The northern Gulf of Mexico Basin, although one of the most intensely studied and explored regions in North America, is also one of the most structurally complex (Figs. 1 and 2). Cenozoic depocenters contain abundant growth faults of a variety of shapes, orientations, sizes, and complexities. In addition, salt domes, flows, and massifs combine to form a complex near-surface pattern that tends to mask the origins of many structures. Not surprisingly, a number of contrasting hypotheses have been proposed to explain the growth faults of this region, among them theories invoking shale diapirism, shale compaction, gravity gliding, salt diapirism, and salt flow. Clearly, the best way to understand the various origins of these features is to observe their structural underpinnings at depth; unfortunately, most of the large growth fault systems of the Texas and Louisiana shelf project below the bottoms of seismic lines of 6- or 7-sec record length. However, as will be discussed in this chapter, deep seismic data now available from the Louisiana slope greatly illuminate the spectacular structural development of this province. In addition, palinspastic reconstructions are useful for analyzing the structural development of these features, and for constraining hypotheses on their origins. Prior to discussing the Cenozoic tectonic development of the northern Gulf of Mexico—the main focus of this chapter—we will briefly review the pre-Cenozoic framework and basic Cenozoic depositional patterns of the Gulf of Mexico Basin, both of which influenced Cenozoic structural styles. The Gulf of Mexico Basin (Fig. 1) was initiated in the late Middle to early Late Jurassic as a result of crustal attenuation and sea-floor spreading associated with the breakup of the supercontinent Pangea.

Geological evolution of the Caribbean region; A plate-tectonic perspective

2015-04-04
James Pindell , S. F. Barrett
The result of a major international effort involving authors and organizations from 13 countries, this volume summarizes the complex geology and tectonic evolution of the Caribbean plate and its relation … The result of a major international effort involving authors and organizations from 13 countries, this volume summarizes the complex geology and tectonic evolution of the Caribbean plate and its relation to the adjacent North American, South American, Nazca, and Cocos plates. Focuses on regional geology and geophysics, magmatic processes, neotectonic features, geologic hazards, and energy and metallic resources. Contrasting views for the Mesozoic and Cenozoic geological evolution are presented in chapters on plate tectonics and mantle surge tectonics. Chapters on marine geology and geophysics are new syntheses for the entire Caribbean region. Highlights of the volume include extensive bibliographies and new syntheses of stratigraphic-lithologic columnar sections, seismicity, gravity and magnetic anomalies, neotectonic features, resource data, and crustal properties.

Introduction to marine biogeochemistry

1993-06-01
Peter J. Wangersky

MESOZOIC-CENOZOIC PALEOGEOGRAPHIC AND GEODYNAMIC EVOLUTION OF SOUTHERN SOUTH AMERICA

1988-06-01
Miguel A. Uliana , Kevin T. Biddle
ln this presentation, we compare the paleogeographie evolution of continental South America with the established plate tectonic history of the oceanic crust of the South American and African Plates. Major … ln this presentation, we compare the paleogeographie evolution of continental South America with the established plate tectonic history of the oceanic crust of the South American and African Plates. Major paleogeographic changes that have occurred in the last 200 million years are illustrated by reconstructions at 200, 160, 120, 100, 70, 50, 20, and 5 Ma. The se reconstructions show location and type of magmatic activity, types and arnounts of subsidence, and transgressions and regressions of shorelines. The latter are eompared with proposed eustatie sea-Ievel ehanges. The sequence of events documented by the reconstructions begins in the mid-late Triassic with the development of successor troughs and intra-plate domes and sags that represent the prelude to the rupture of Gondwanaland. Extension eontinued through the Late Jurassie resulting in widespread faulting and intra-plate volcanism. Large-seale drift occurred by the Early Cretaceous (late Neocomian) accompanied by the formation of epicontinental rifts and sags, and a well-defined magmatic are along the western margin of South America. In the mid-Cretaceous the Atlantic Basin was well developed and rimmed by trailing-margin sedimentary prisms, and global changes in plate motions led to the reorganization of the subduction system along the Pacific margin of South America. The Late Cretaceous, a time of relative tectonic quiescence in southern South America, recorded the maximum flooding of the continent by Atlantic waters. Plate tectonic reorganization in the Paleogene introduced new patterns of Andean deformation and magmatism, and coincided with general marine retreat. Magmatic arc buildup and renewed marine flooding followed in the early Neogene, with the late Neogene being dominated by pronounced shortening, Cordilleran uplift, and marine withdrawal.
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Modificaciones al Sistema de Clasificación Climática de Köppen

2004-01-01
Enriqueta García

Subaerial Exposure Environment

1983-01-01
Mateu Esteban , Colin F. Klappa
For more than 100 years geologists have been ex amining and describing modern sediments with an eye toward using characteristic features to aid in the interpretation of depositional settings of … For more than 100 years geologists have been ex amining and describing modern sediments with an eye toward using characteristic features to aid in the interpretation of depositional settings of ancient strata. This field of interest developed particularly during the 1950s and 1960s with the creation of detailed models for modern carbonate deposition in Florida, the Bahamas, Cuba, the Persian Gulf, Belize, Pacific atolls, the Great Barrier Reef and other areas. An understanding of the depositional environments of these modern models, coupled with increased understanding of diagenetic effects, has led to vastly improved interpretations of ancient limestones. Such models also improved the "predictability" of many carbonate reservoir rocks.In spite of the great strides made in our knowledge about carbonate depositional environments, their characteristic features have never been synthesized in a single work. Although excellent textbooks exist which describe some aspects of the interpretation of both ancient strata and modern sediments, systematic treatment of the entire subject is available only in the primary literature.This book is an attempt to bring together this widely disseminated literature. The volume is specifically designed for use by the non—specialist-the petroleum geologist or field geologist—who needs to use carbonate depositional environments in facies reconstructions and environmental interpretations. Yet it is hoped that the book will also serve as a valuable reference for the specialist or advanced graduate student.Toward that purpose, the book is extensively illustrated with color diagrams and photographs of sedimentary structures and facies assemblages. The text focuses on the recognition of depositional environments rather than on the hydrodynamic mechanisms of sediment movement.

Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate

1972-01-01
BRUCE T. MALFAIT , M. G. Dinkelman
Research Article| February 01, 1972 Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate BRUCE T MALFAIT; BRUCE T MALFAIT Department of Oceanography, Oregon State University, Corvallis, … Research Article| February 01, 1972 Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate BRUCE T MALFAIT; BRUCE T MALFAIT Department of Oceanography, Oregon State University, Corvallis, Oregon 97331 Search for other works by this author on: GSW Google Scholar MENNO G DINKELMAN MENNO G DINKELMAN Department of Oceanography, Oregon State University, Corvallis, Oregon 97331 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1972) 83 (2): 251–272. https://doi.org/10.1130/0016-7606(1972)83[251:CTAIAA]2.0.CO;2 Article history received: 07 Jun 1971 rev-recd: 23 Aug 1971 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation BRUCE T MALFAIT, MENNO G DINKELMAN; Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate. GSA Bulletin 1972;; 83 (2): 251–272. doi: https://doi.org/10.1130/0016-7606(1972)83[251:CTAIAA]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Convergence of the North and South American blocks and northeastward movement of the East Pacific-Caribbean plate during the Late Cretaceous and early Tertiary led to the Laramide tectonic and igneous activity that has been recorded in the geology of the circum-Caribbean region. Volcanism in Central America and the initiation of major transcurrent faulting along northern South America during the late Eocene suggest that the Caribbean decoupled from the East Pacific plate near the end of the Laramide Orogeny. Lack of post-Eocene structural activity in the Greater Antilles is consistent with the initiation of eastward movement of the Caribbean plate during the Eocene.The evolution of the Cayman Trough and the history of orogenic activity in Cuba can be explained by assuming that Caribbean lithosphere was transferred to the Americas plate as the trough developed from west to east. As each new section was added to the eastward-growing trough, a new transform fault formed in the Caribbean lithosphere to connect the eastern end of the trough with the Cuban Trench. This west to east stepping of the plate boundary transferred "Caribbean" lithosphere to the Americas plate and allowed underthrusting and related tectonic activity to continue longer in eastern than in western Cuba. The presence of intermediate depth earthquakes and high seismicity along the Puerto Rico Trench suggest that the Atlantic lithosphere which underthrust Puerto Rico prior to the Oligocene is beginning to break away from the Americas plate. Fault displacements inferred along the Caribbean-Americas boundary in the Greater Antilles are equivalent to a constant post-Eocene eastward movement of 0.5 cm/yr for the Caribbean plate. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Uplift history of the Central and Northern Andes: A review

2000-07-01
Kathryn M. Gregory‐Wodzicki
Research Article| July 01, 2000 Uplift history of the Central and Northern Andes: A review Kathryn M. Gregory-Wodzicki Kathryn M. Gregory-Wodzicki 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964-8000, … Research Article| July 01, 2000 Uplift history of the Central and Northern Andes: A review Kathryn M. Gregory-Wodzicki Kathryn M. Gregory-Wodzicki 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964-8000, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Kathryn M. Gregory-Wodzicki 1Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964-8000, USA Publisher: Geological Society of America Received: 25 Sep 1998 Revision Received: 18 Nov 1999 Accepted: 22 Nov 1999 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2000) 112 (7): 1091–1105. https://doi.org/10.1130/0016-7606(2000)112<1091:UHOTCA>2.0.CO;2 Article history Received: 25 Sep 1998 Revision Received: 18 Nov 1999 Accepted: 22 Nov 1999 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Kathryn M. Gregory-Wodzicki; Uplift history of the Central and Northern Andes: A review. GSA Bulletin 2000;; 112 (7): 1091–1105. doi: https://doi.org/10.1130/0016-7606(2000)112<1091:UHOTCA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The elevation of the Andean Cordillera is a crucial boundary condition for both climatic and tectonic studies. The Andes affect climate because they form the only barrier to atmospheric circulation in the Southern Hemisphere, and they intrigue geologists because they have the highest plateau on Earth formed at a noncollisional plate margin, the Altiplano-Puna. Yet, until recently, few quantitative studies of their uplift history existed. This study presents both (1) a review of the quantitative paleoelevation estimates that have been made for the Central and Colombian Andes and (2) an examination of the source and magnitude of error for each estimate. In the Central Andes, paleobotanical evidence suggests that the Altiplano-Puna had attained no more than a third of its modern elevation of 3700 m by 20 Ma and no more than half its modern elevation by 10.7 Ma. These data imply surface uplift on the order of 2300–3400 m since the late Miocene at uplift rates of 0.2–0.3 mm/yr. Paleobotanical and geomorphological data suggest a similar uplift history for the Eastern Cordillera—namely no more than half the modern elevation present by 10 Ma. No evidence exists for an exponential increase in uplift rate, as has been interpreted from fission-track data. These uplift rates mostly reflect mean surface uplift rather than rock uplift—that is, uplift of material points—because little dissection of the western Eastern Cordillera has occurred south of lat 19°S and of the Altiplano-Puna. Thus, the Central Andean Plateau appears to be young. In the Colombian Andes, paleobotanical data imply rapid uplift of the Eastern Cordillera between 2 and 5 Ma at rates on the order of 0.6–3 mm/yr. However, some of this uplift is likely rock uplift due to erosion-driven isostatic rebound rather than mean surface uplift. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The Andes : active subduction orogeny

2006-01-01
Onno Oncken

Análisis de procesos de fabricación y viabilidad de la manufactura y sustitución de carbón ecológico a base de fibra de coco.

2025-06-19
Jefferson Fabian Alcívar-Gracia , Damián Alexi Junco-Lucas , Luis Alejandro Intriago-Alcívar | MQRInvestigar
El presente artículo analiza la viabilidad técnica, económica y ambiental del biocarbón producido a partir de fibra de coco como una alternativa real para sustituir combustibles fósiles en procesos industriales. … El presente artículo analiza la viabilidad técnica, económica y ambiental del biocarbón producido a partir de fibra de coco como una alternativa real para sustituir combustibles fósiles en procesos industriales. Mediante una revisión bibliográfica especializada, complementada con recolección de datos locales en la ciudad de Manta (Ecuador), se estudian tanto los métodos de producción como las propiedades del biocarbón, sus costos asociados, su rendimiento energético y sus implicaciones sociales y ambientales. Los resultados evidencian que el biocarbón obtenido mediante pirólisis controlada presenta un poder calorífico que oscila entre 16,7 y 25,0 MJ/kg, una eficiencia térmica del 70 al 80 %, y una combustión relativamente limpia, con baja producción de cenizas y emisiones. Su composición fisicoquímica, caracterizada por un alto contenido de carbono (65–75 %), pH alcalino (8,5–9,2) y estructura porosa (hasta 220 m²/g), lo hace adecuado tanto para uso energético como para aplicaciones agrícolas o ambientales. En cuanto al costo de producción, se identificó un valor promedio de entre USD 0.35 y 0.45 por kilogramo, con un costo energético estimado de USD 65–75 por GJ, lo que lo ubica como una opción competitiva frente al carbón vegetal (USD 0.90/kg; &gt;90 USD/GJ) y cercana al GLP industrial (USD 60–65/GJ). A diferencia del diésel y el GLP, el biocarbón no depende de subsidios estatales, lo que le otorga estabilidad de precios y lo hace más sostenible a largo plazo. Otro punto destacado es su bajo impacto ambiental: las emisiones de CO₂ equivalente del biocarbón oscilan entre 0.015 y 0.030 tCO₂e por GJ, valores notablemente inferiores a los del diésel (0.074–0.085 tCO₂e/GJ) y el carbón vegetal (0.10–0.12 tCO₂e/GJ). Esto lo convierte en una opción estratégica dentro de los compromisos climáticos del país. Desde lo social, el biocarbón representa una oportunidad para generar empleo rural, valorizar residuos agroindustriales y fomentar cadenas productivas locales. Su implementación, sin embargo, requiere superar desafíos como la falta de normativas específicas, el bajo desarrollo tecnológico en procesos de pirólisis y la escasa difusión sobre sus beneficios. En conjunto, los datos analizados permiten concluir que el biocarbón de fibra de coco no solo es técnicamente viable, sino que también es económicamente competitivo y ambientalmente responsable. Su adopción, especialmente en sectores industriales de demanda térmica media, puede contribuir a una transición energética más equitativa, sostenible y alineada con los recursos locales disponibles.

Deep processes and surface effects of the Meso-Cenozoic Caribbean subduction system

2025-06-18
Liang Zhao , Rixiang Zhu , Hao Shen +5 more | Science China Earth Sciences

Chevron Folds: un recurso interactivo para visualizar el mecanismo de deslizamiento por flexión (flexural slip) en el desarrollo de pliegues tipo chevron

2025-06-17
Alberto Vásquez-Serrano | Deleted Journal
Chevron Folds es un programa computacional que funciona bajo el sistema operativo Windows® y fue desarrollado en Visual Basic 6®. El programa busca mostrar de manera interactiva el desarrollo de … Chevron Folds es un programa computacional que funciona bajo el sistema operativo Windows® y fue desarrollado en Visual Basic 6®. El programa busca mostrar de manera interactiva el desarrollo de pliegues tipo chevron bajo el mecanismo de deslizamiento por flexión (flexural slip). Chevron Folds utiliza como variables de entrada el ángulo de inclinación de los flancos del pliegue (α), el espesor de la capa competente (t1) y la longitud del flanco del pliegue (l/2). Con estas variables de entrada se obtiene como resultado una simulación del desarrollo del pliegue, la cantidad de acortamiento que acomoda el pliegue, el deslizamiento total entre las capas y dos gráficos que muestran la variación del acortamiento y deslizamiento total en función del ángulo de inclinación del flanco (α). El mecanismo de deslizamiento por flexión puede ser el principal en el desarrollo del pliegue hasta el ángulo de bloqueo (ángulo entre flancos = ~60°). Este programa puede ser una herramienta de apoyo valiosa para estudiantes de licenciatura y posgrado en Ciencias de la Tierra en las clases de Geología Estructural.

Desarrollo de una propuesta didáctica para el análisis morfológico de partículas clásticas del tamaño de las gravas con el programa Forma

2025-06-17
José Luis Ventura-Donjuan , Aarón Ulises Ocampo-Díaz , Jorge Aceves de Alba +1 more | Deleted Journal
Este trabajo presenta una nueva propuesta didáctica para la enseñanza del análisis de la forma de partículas clásticas del tamaño de las gravas, de sus índices y factores en Sedimentología … Este trabajo presenta una nueva propuesta didáctica para la enseñanza del análisis de la forma de partículas clásticas del tamaño de las gravas, de sus índices y factores en Sedimentología y disciplinas relacionadas. Parte fundamental de esta propuesta es la presentación aquí de Forma, un programa libre, gratuito y multiplataforma desarrollado en JAVA. Para la implementación de la propuesta didáctica, se diseñaron y aplicaron dos ejercicios prácticos que involucran el análisis de gravas de tres ambientes sedimentarios utilizando el programa Forma. Este programa facilita la determinación rápida y eficaz de la forma y sus diversos índices y factores, permitiendo su visualización gráfica y la obtención de valores para cada partícula. La cuantificación de estos valores es crucial en Sedimentología, ya que proporciona valores objetivos de la morfología de los clastos, esencial para inferir procesos de abrasión y fragmentación ocurridos durante el transporte sedimentario. El programa Forma ofrece herramientas para visualizar, graficar y calcular estos parámetros, además de permitir la exportación de resultados para su análisis estadístico en programas como Microsoft Excel, R o PAST, y la generación de figuras en formato JPEG y PDF. Se espera que estos ejercicios puedan ser adaptados por cada profesor o estudiante de acuerdo con los datos disponibles, las áreas de interés o los objetivos de cada curso. En conjunto, esta propuesta didáctica enfatiza el uso del programa Forma para el análisis y visualización de datos, complementándose con otras herramientas para el análisis estadístico y la generación de imágenes, contribuyendo al desarrollo de habilidades esenciales para los futuros profesionales.

Modelos de distribución de edades de aguas subterráneas (LPMs) y su aplicación en el acuífero Pampeano usando Clorofluorocarbonos (CFCs)

2025-06-13
Alejandro Basaldúa , Emiliano F. Alcaraz , Daniel Martínez | Acta Geológica Lilloana
Se presentan los conceptos fundamentales de la aplicación de trazadores de edad y 26 modelos de parámetros agrupados (LPMs, por sus siglas en inglés) para la datación de aguas 27 … Se presentan los conceptos fundamentales de la aplicación de trazadores de edad y 26 modelos de parámetros agrupados (LPMs, por sus siglas en inglés) para la datación de aguas 27 subterráneas. Como caso de estudio, se analiza la edad del agua subterránea del acuífero 28 Pampeano, en el sureste de la Provincia de Buenos Aires, mediante el uso de 29 clorofluorocarbonos (CFC-11, CFC-12 y CFC-113) medidos en muestras de un pozo somero 30 y un manantial. Los resultados indicaron edades aparentes distintas para cada CFC, variando 31 entre 31 años (CFC-113 en el pozo) y 44 años (CFC-11 en el manantial). Se realizó un 32 análisis más detallado utilizando estas mediciones en combinación con LPMs para representar 33 diversas distribuciones de edades. Este enfoque permitió explicar las variaciones en las 34 edades aparentes como resultado de la mezcla de aguas de diferentes edades dentro de cada 35 muestra. Los mejores ajustes se lograron con modelos dispersivos y utilizando CFC-12 y 36 CFC-113, obteniendo edades promedio de 38,8 años para el pozo y 34,9 años para el 37 manantial. La similitud en las edades medias de ambos puntos se debe a la captación en el 38 pozo de líneas de flujo con tiempos de tránsito similares a los que se descargan naturalmente 39 en el manantial. Las bajas concentraciones de CFC-11 en ambas muestras y la imposibilidad 40 de aplicar este trazador en los modelos de ajuste se atribuyen a la probable degradación 41 microbiana de este compuesto en el sistema.

Determinação da temperatura basal inferior, soma térmica e do filocrono da salsa Stella

2025-06-11
Kemere Marques Vieira Barbosa , Rosandro Boligon Minuzzi | Brazilian Journal of Animal and Environmental Research
A relação entre temperatura do ar e o desenvolvimento de culturas, permite otimizar práticas de manejo agrícola, como previsão de estádios de crescimento e épocas ideais de semeadura. Objetiva-se determinar … A relação entre temperatura do ar e o desenvolvimento de culturas, permite otimizar práticas de manejo agrícola, como previsão de estádios de crescimento e épocas ideais de semeadura. Objetiva-se determinar a temperatura basal inferior (Tb), soma térmica (ST) e o filocrono da salsa (Petroselinum crispum), variedade Stella (lisa). Foram realizadas cinco safras em ambiente protegido localizado em Florianópolis, com medições fenológicas da 2ª à 7ª folha. A Tb foi estimada por três métodos: menor desvio padrão, coeficiente de regressão e desenvolvimento relativo, resultando em valor médio de -5,0 °C. Com este valor de Tb, determinou-se a ST, aplicando o método simplificado de graus-dia para cada uma das safras, onde chegou-se ao valor médio de 816,8 graus-dia acumulado (GDA). A média do filocrono entre as cinco safras foi de 27,9 °C dia.folha-1, havendo uma necessidade média de 170 GDA para a salsa emitir cada uma, da 2º a 7º folha.

The Deep Lithospheric Structure of Terrane Accretion as Revealed Through Patterns of Seismicity Associated With the Collision of the Panamá–Chocó Block and South America Beneath Cauca, Colombia

2025-06-01
Brandon T. Bishop , L. M. Warren , Pablo Aravena +5 more | Journal of Geophysical Research Solid Earth
Abstract The Cauca region is the only documented site in the world where extensive intermediate depth seismicity occurs over multiple decades above a subducting slab. Here, the subducting Nazca oceanic … Abstract The Cauca region is the only documented site in the world where extensive intermediate depth seismicity occurs over multiple decades above a subducting slab. Here, the subducting Nazca oceanic plate descends beneath a mosaic of terranes derived from the Caribbean plate and accreted to continental South America from the Cretaceous to the present. Through relative relocation of &gt;6,000 earthquakes from 2010 to 2019 we show that seismic activity within the Nazca slab is concentrated immediately inboard of the most recently accreted terrane (the Panamá–Chocó Block) and that supraslab seismicity is occurring within the subducted continuation of this terrane. The deepest extent of this seismicity occurs only within the Colombian forearc and a gap in the active volcanic arc, indicating that the continuation of this terrane at depth has perturbed the thermal structure of the subduction zone. This perturbation is likely what permits brittle failure to occur above the slab. Within the context of the long‐term evolution of the Colombian subduction zone, this seismicity must represent either a transient phenomenon as the continuation of the Panamá–Chocó Block warms and becomes incorporated into the convecting mantle wedge or a site where fluids released by the subducting Nazca slab have been focused, promoting hydrofracture. While additional tests are necessary to distinguish between these possibilities, seismicity within the Nazca slab is most intense directly beneath the locations where supraslab seismicity is concentrated, consistent with hydrofracture due to fluids escaping the slab. Similar transient processes may have affected terrane accretion in the geologic past.

Corrigendum to “Growth of complex volcanic ash aggregates in the Tierra Blanca Joven eruption of Ilopango Caldera, El Salvador” [Journal of Volcanology and Geothermal Research, Volume 431, (2022), 107670]

2025-06-01
Henry Hoult , Richard J. Brown , Alexa R. Van Eaton +3 more | Journal of Volcanology and Geothermal Research

Caracterización de minerales de alteración hidrotermal: Proyecto minero la Bonita, Ecuador

2025-06-01
Katherine Michelle Diaz Medina | Dominio de las Ciencias
La caracterización de minerales de alteración hidrotermal es una herramienta clave en la exploración geológica, especialmente en contextos donde se presume la existencia de sistemas tipo pórfido. El presente estudio … La caracterización de minerales de alteración hidrotermal es una herramienta clave en la exploración geológica, especialmente en contextos donde se presume la existencia de sistemas tipo pórfido. El presente estudio se desarrolló en el sector comprendido entre las quebradas Chorrera Chico y El Bicundo, en el cantón González Suárez, provincia de Sucumbíos (Ecuador), una zona con antecedentes de mineralización polimetálica reconocida desde la década de 1990. El objetivo principal fue caracterizar los minerales de alteración hidrotermal presentes en rocas aflorantes mediante análisis macroscópico y petrográfico, para delimitar zonas de interés hidrotermal y vincularlas con modelos reconocidos de depósitos tipo pórfido. La metodología se estructuró en cuatro fases: revisión bibliográfica, trabajo de campo con mapeo geológico a escala 1:5.000, análisis de laboratorio incluyendo láminas delgadas y descripción petrográfica, y la elaboración de mapas de distribución mineralógica. Los resultados permitieron identificar tres litologías principales (granodiorita, cuarzo monzodiorita y una litofacie brechada) con ensambles de alteración hidrotermal como clorita, sericita, epidota, illita y pirita, dispuestos en patrones compatibles con alteración clorítico-sericítica y fílica. Se concluye que el área de estudio evidencia un sistema hidrotermal activo y zonado, con alto potencial metalogénico, lo que proporciona una base técnica relevante para orientar futuras campañas de perforación y exploración minera en el Proyecto La Bonita.

¿Es necesario el estado 100% libre de litiasis en los casos de cálculos coraliformes?

2025-06-01
Gian Paulo Giovanni Freschi , D. Pucharelli Resuto , R. Astolfi +2 more | Actas Urológicas Españolas

Isoterma de Curie en Chile central: análisis del gradiente y flujo geotérmico en la zona continental

2025-05-30
David Cáceres Araya | Andean geology
This study explores the relationship between magnetometry and thermodynamics in heat transfer within the Earth’s crust in central Chile. The radially averaged power spectrum analysis of magnetic data was used … This study explores the relationship between magnetometry and thermodynamics in heat transfer within the Earth’s crust in central Chile. The radially averaged power spectrum analysis of magnetic data was used to determine the Courie point depth, from the city of La Serena (~30° S) to San Fernando (~34.5° S), and from the Andes Mountains (~70.5° W) to approximately 82° W. Offshore, the Curie isotherm shows an average depth of 22 km and is tentatively correlated with the Juan Fernández Ridge. Inland, significant differences are observed; on the one hand, the Curie isotherm reaches shallower depths, averaging 12 km from Ovalle to Illapel; on the other hand, a deeper zone, at approximately 39 km depth, is identified northeast of Valparaíso. An empirical equation is then employed to calculate the thermal conductivity of the rocks and determine the geothermal heat flow. The average geothermal gradient in the continental region of central Chile is 20 °C/km, with a maximum of 45 °C/km in the locality of Canela. In the Metropolitan Region of Santiago, the average heat flow is 50 mW/m², with a maximum of 57 mW/m² in the commune of Paine. The results obtained are consistent with a previous radiogenic study in the Santiago basin, suggesting that the method used in this research constitutes a novel technique that can be replicated to other regions of the country. The information provided in this contribution can be utilized for the design of geothermal energy systems and to improve the understanding of geological processes in the region.

Study of the Abitagua Batholith in the Sub-Andean Zone of Ecuador, using velocity models from seismic tomography

2025-05-30
Dennys Chalco , Sebastián Araujo , Santiago Balcázar Loaiza +1 more | Andean geology
The Abitagua Batholith is a Mid to Late Jurassic intrusive body in the Sub-Andean Zone of Ecuador. This batholith is theorized to be the source of alluvial gold in the … The Abitagua Batholith is a Mid to Late Jurassic intrusive body in the Sub-Andean Zone of Ecuador. This batholith is theorized to be the source of alluvial gold in the Amazon rivers that drain from it, although due to its difficult access and location along protected areas it remains largely unexplored. This work aims to study the Abitagua Batholith using seismic velocity models that provide absolute and relative P-wave velocity and Vp/Vs ratios based on the inversion of the earthquake travel-time data recorded by the Ecuadorian survey networks RENSIG, RENAC, and ROVIG, and some stations of the Colombian Geological Service near the border with Ecuador. We use the absolute and relative P-wave velocity tomography models to describe the batholith’s vertical and horizontal components. The resolution in our velocity models displays values larger than 0.8 and cover all the crust and the upper mantle to depths of seventy kilometers. We identify two velocity anomalies, possibly associated with magmatic reservoirs under the batholith that, together with hypocenter data, suggest more recent magma intrusions. We conclude that these magmatic bodies relate to potential gold-bearing intrusions, which seem to concentrate near the transition zone between the negative and positive velocity anomalies, five kilometers north of the Jatunyaku River.

Petrografía y proveniencia de las areniscas del Grupo Morro Solar (Berriasiano superior-Valanginiano) de Lima (77°01’ O, 12°10’ S): implicancias geodinámicas y paleogeográficas

2025-05-30
Aldo Alván , Astrid H. Criales , Augusto Bernuy | Andean geology
The sedimentary record of the continental margin of Lima, Peru (77°01’ W, 12°10’ S) plays a significant role in understanding the regional geology given its location along the westernmost part … The sedimentary record of the continental margin of Lima, Peru (77°01’ W, 12°10’ S) plays a significant role in understanding the regional geology given its location along the westernmost part of a siliciclastic platform developed during the Early Cretaceous, prior to the Andean orogeny. In this contribution, the mineral composition of 20 samples of litho-quartzose sandstones and quartzose sandstones from the Salto del Fraile, La Herradura, and Marcavilca formations of the Morro Solar Group (Upper Berriasian-Valanginian) is examined by using the Gazzi-Dickinson method to shed light into sediment provenance. Results reveal that the sediments of the Morro Solar Group accumulated after the exhumation of a recycled orogen located in the Eastern Cordillera, which includes the Marañón Metamorphic Complex. This orogen is interpreted to be composed of sedimentary and volcanic rocks of Paleozoic and Triassic age. A minor provenance of metamorphic Precambrian rocks from the Amazon Craton is not totally discarded.

Numerical Modeling Integrated With Field Observations and Analytical Data of the 2021 Cumbre Vieja Eruption Improves Understanding of Eruption Dynamics at Mafic Volcanoes

2025-05-28
Elisa Biagioli , Giuseppe La Spina , Margherita Polacci +3 more | Journal of Geophysical Research Solid Earth
Abstract Abrupt transitions in eruptive style are common at mafic volcanoes, possibly leading to styles that potentially damage infrastructures and threaten the surrounding communities. During the 19th September–13th December 2021 … Abstract Abrupt transitions in eruptive style are common at mafic volcanoes, possibly leading to styles that potentially damage infrastructures and threaten the surrounding communities. During the 19th September–13th December 2021 Cumbre Vieja eruption (La Palma, Canary Islands), rapid changes in eruptive style were observed, from vigorous lava fountaining to sporadic intense ash columns, alongside continuous lava effusion, providing an ideal case study for investigation of the mechanisms underlying such transitions. We used a 1D steady‐state numerical model for magma ascent to study the driving processes behind the eruptive style transitions. The model considers the complex and non‐linear interdependence among the major processes occurring during magma ascents, such as temperature and viscosity evolution, non‐ideal gas behavior, outgassing, and disequilibria in crystallization and volatile exsolution. Input parameters of the simulations (inlet pressure and temperature, water and CO 2 content, initial phenocrystal content) are constrained by analytical studies and empirical data. Simulation outputs are compared with field observations and analytical data. Results suggest that a change in the degree of coupling between gas and melt might have caused the eruptive style change. We hypothesize that a change in the conduit geometry triggered this shift. One possible explanation could be a shallow branching of the conduit, which leads to variable magma and gas partitioning between ramifications. Another possible cause could be the temporary partial collapse of the conduit walls near the surface, which might have generated an acceleration of magma, reducing volatile outgassing, increasing magmatic strain, and consequently triggering the observed transition to explosive activity.

Claron basin provenance shift from Sevier-Laramide compression to Basin and Range extension

2025-05-26
David M. Malone , Grace Stevens , Sarah Rose Lesmann +6 more
The Eocene-Oligocene Brian Head Formation is the basal volcanic unit throughout much of the southern Marysvale volcanic field but rests atop Sevier-Laramide synorogenic strata of the Claron foreland basin in … The Eocene-Oligocene Brian Head Formation is the basal volcanic unit throughout much of the southern Marysvale volcanic field but rests atop Sevier-Laramide synorogenic strata of the Claron foreland basin in southern Utah. The Brian Head Formation reaches 300 m in thickness and consists of light-colored volcaniclastic sandstone, siltstone, mudstone, and minor conglomerate and airfall tuff; in northern exposures, the upper part locally contains a volcanic section of lava flows, ash-flow tuff, and volcanic mudflow breccia. These rocks were deposited in a slowly aggrading fluvial to lacustrine depositional environment distal tothe Indian Peak caldera complex to the west. We sampled three volcaniclastic sandstone units near the top of the formation, specifically near Haycock Mountain and along the southern and western flanks of the Sevier Plateau near Casto Butte and Blind Spring Mountain. The sandstone beds are compositionally and texturally immature and classify as lithic and arkosic wacke. U-Pb geochronological data for samples from the three sites were obtained on zircon by inductively coupled plasma mass spectrometry (ICP-MS) at the University of Arizona Laserchron Center. A total of 370 zircon crystals were analyzed. Most zircons were pale, translucent, and euhedral. The detrital zircon age spectra of the three sites are statistically indistinguishable. Each sample contained greater than 80% Paleogene zircons and had prominent age peaks of about 34.5 Ma. We interpret that the maximum depositional age is about 33.4 Ma. Older zircons range from Mesozoic to Archean in age. We suggest that the Brian Head Formation was sourced from the IndianPeak caldera and its environs, which are greater than 150 km to the west. Thus, Brian Head deposition in the Claron basin represents the transition from a Sevier-Laramide foreland basin characterized by the synorogenic Claron Formation to a system dominated by more distally derived sediments from the Indian Peak caldera complex, which is probably the most prominent eruptive center on the Nevadaplano uplift.

Morphostructural controls on heat flow and fluid circulation in the Valle de Nereidas geothermal field, Nevado del Ruiz, Northern Andes, Colombia

2025-05-23
Luis Alvaro Botero-Gómez , Hugo Murcia , Martha Gabriela Gómez‐Vasconcelos +3 more

The Magma plumbing system and seismo-tectonics of the Guatemala-Mexico triple junction as revealed by the seismicity of the Tacaná volcano before and after the 2017 Mw8.2 Chiapas earthquake

2025-05-13
D. Legrand , Mathieu Perton , Zack Spica +7 more
Summary The triple junction between the North American, Caribbean, and Cocos plates at the Guatemala-Mexico border is not well understood. It forms a broad region from around the active Tacaná … Summary The triple junction between the North American, Caribbean, and Cocos plates at the Guatemala-Mexico border is not well understood. It forms a broad region from around the active Tacaná volcano up to the Guatemala City graben. Tacaná is the westernmost active volcano of the Central American volcanic arc and is located at the intersection of four major active faults: the Polochic, Motagua, Jalpatagua, and Tonalá faults. Using seismicity around the Tacaná volcano, we show that there is moderate to low tectonic seismic activity between the Guatemala City graben and the Tacaná volcano, possibly related to the ancient extremes of the Motagua and Jalpatagua faults. Therefore, we speculate that the triple junction would be located onshore, around the Tacaná volcano. We located earthquakes around the Tacaná volcano between January 2017 and October 2018, a period that includes the large Mw8.2 Tehuantepec (Chiapas) earthquake of 8 September 2017, located ∼190 km away. We identified four distinct types of seismicity, interpreted as having tectonic, hydrothermal, intermediate depth magmatic, and deep magmatic origins. The tectonic seismicity occurred at depths between ∼5 km and ∼30 km b.s.l., and may be associated with three faults around the Tacaná volcanic complex. These faults are oriented in NE-SW, aligned with the four Tacaná volcanic edifices; NW-SE, consistent with the Jalpatagua fault; and approximately EW, corresponding to the Motagua fault. The hydrothermal seismicity is observed at shallow depths, from the subsurface to about 2 km b.s.l., predominantly in the western sector of the Tacaná summit, and partially beneath the San Antonio volcano, an area known for intense hydrothermal activity. This seismicity is spatially related to the shallow portions of the same three faults described above. The intermediate depth magmatic seismicity is detected at depths between 5 and 12 km b.s.l. and is interpreted to be related to the presence of a shallow magma chamber beneath the Tacaná volcanic complex. Finally, the deep magmatic seismicity is located in the eastern part of the Tacaná, at depths ranging from 15 km to about 22 km b.s.l. This seismicity is interpreted to be due to a vertical dike intrusion that connects a deep magma reservoir located between 30 km and 40 km depth, to the hypothesized shallower magma chamber associated with the intermediate depth seismicity.

LA PLANEACIÓN Y DESARROLLO DE LA GESTIÓN DEL RIESGO DE DESASTRES: Una mirada desde la vulnerabilidad sísmica en Lima Metropolitana

2025-05-10
Leonardo Saravia Parra , Fabrizio Del Carpio Delgado , Alberto Cristobal Flores Quispe +2 more
The fatal consequences of dangerous natural events throughout the history of mankind, which have exceeded the response capacity of countries such as Japan, have led to the evaluation, design and … The fatal consequences of dangerous natural events throughout the history of mankind, which have exceeded the response capacity of countries such as Japan, have led to the evaluation, design and monitoring of disaster risk management models. The general objective of this research was to analyze the planning and development of disaster risk management in Peru, with a focus on the seismic vulnerability of Metropolitan Lima. For this purpose, a case study was carried out based on a review of technical and scientific literature, as well as on the verification of the criteria suggested by the United Nations Office for Disaster Risk Reduction. The PLANAGERD 2014-2021, the PLANAGERD 2022- 2030 and the evaluation report carried out by the Presidency of the Council of Ministers were taken as the basis for analysis. The results obtained showed that there are two criteria that have not been fully considered. However, disaster risk management in the Municipality of Lima is being carried out at an acceptable level. In conclusion, there is an urgent need for effective coordination among all the actors involved to address the weaknesses detected and thus mitigate the risk in the event of a major earthquake. In addition, it is essential to reduce the worrying vulnerability of the various structures that house almost 12 million people in Metropolitan Lima.

Understanding the Changing Dynamics of the 2016-2022 Nevados de Chillán, Chile Eruption through Erupted Volume and Surface Deformation

2025-05-08
Elizabeth Eiden , M. E. Pritchard , P. Lundgren +7 more
<title>Abstract</title> Improving forecasting of eruptive hazards is a top priority of the volcanological community and can be difficult to do in complex eruptions. From 2016-2022, Nevados de Chillán, Chile, underwent … <title>Abstract</title> Improving forecasting of eruptive hazards is a top priority of the volcanological community and can be difficult to do in complex eruptions. From 2016-2022, Nevados de Chillán, Chile, underwent a complex eruption with multiple transitions between effusive and explosive activity, resulting in four domes and eight lava flows. We combine a decade of InSAR time series data with 4.5 years of data at five local GNSS stations to define three distinct periods of co-eruptive surface subsidence and three periods of co-eruptive uplift. We use Markov chain Monte Carlo methods to invert for the source depth and volume change necessary to cause each surface deformation period. We find evidence for the third uplift phase source to be slightly deeper (6.4 ± 0.4 km below ground level) compared to the first two periods of uplift (4.4 ± 0.2 km and 4.8 ± 0.1 km below ground level). We used topographic data from helicopter overflights and Pléiades and Maxar satellites to derive the total erupted volume (~1.1 x 107 m3) between December 2017 and November 2022. We compare these data sets with optical imagery from Planet satellites, thermal time series from Terra’s ASTER instrument, and seismic data. Each effusive phase begins with larger effusion rates that taper off. The episodes of surface uplift coincide with increases in effusion rate and seismicity, indicating a new supply of magma. The combination of ground-based, airborne, and satellite-derived datasets provides dense spatial and temporal information on eruption evolution.

Magma recharge and reheating driving the 2021–2023 tephra emissions of Villarrica volcano, southern Andes

2025-05-07
Jorge E. Romero , Francisco Cáceres , Alicia Guevara +7 more

Mountains of the intertropical passive margins and their cartographic representation: methodological proposal in different litostructural arrangements

2025-05-05
Roberto Marques Neto
The core hypothesis of this article considers that methodological approaches related to geomorphological cartography must seek standardization based on landscape types. Thus, a methodological proposal for geomorphological cartography in mountainous … The core hypothesis of this article considers that methodological approaches related to geomorphological cartography must seek standardization based on landscape types. Thus, a methodological proposal for geomorphological cartography in mountainous landscapes is presented, with demonstrations in compartments structured in three distinct lithostructural bases located in the context of Serra da Mantiqueira: nepheline-syenites, gneiss-granites and quartzites. The results showed a similar geomorphological organization for the different compartments, admitting the same methodological approach and the adoption of a unified legend, since the geomorphic facts found were convergent, despite the differences in the geological bases between the areas. It is postulated that the methodological approach presented can be applied to different geomorphological contexts located in the large escarpments of the intertropical passive margins, thus making the universalization of interpretative and technical procedures compatible with the also universal character of this landscapes.

Transition of El Niño to La Niña can be driven by regional perturbations a year ahead

2025-05-02
Chris Kent , Adam A. Scaife , William J. M. Seviour +3 more
Abstract Interannual forecasts provide skilful predictions of El Niño-Southern Oscillation (ENSO) up to a year in advance, however our understanding of what drives the ensemble skill and diversity of outcomes … Abstract Interannual forecasts provide skilful predictions of El Niño-Southern Oscillation (ENSO) up to a year in advance, however our understanding of what drives the ensemble skill and diversity of outcomes across members is limited. Using a fully coupled ocean-atmosphere ensemble forecasting system, we investigate the causality of regional perturbations on the evolution of ENSO at interannual timescales. Using forecasts initialised on 1st November 2009, transplanting more realistic cooler conditions in the South Pacific across ensemble members on 1st January 2010 significantly cools the resulting 2010/2011 winter ENSO one year later. The imposed perturbations migrate equatorward via Wind-Evaporation-Sea surface temperature (WES) feedback and significantly alter tropical zonal gradients during late spring and summer. This drives the ensemble towards La Niña conditions, in line with observations. Repeating the experiment with warmer South Pacific conditions, results in the reverse signal and warms ENSO one year later. Across the experiments we find an almost four-fold increase in probability of La Niña and a three-fold decrease in probability of El Niño, demonstrating that long lead regional perturbations can systematically tip the climate system between ENSO states. Predicted surface conditions are significantly impacted across many parts of the world and the forecast global annual mean surface temperature for 2010 is significantly cooled, resulting in better agreement with observations. Our results demonstrate sensitivity of ENSO evolution and the global climate system to specific regional perturbations and provide new insights for interannual climate prediction.&amp;#xD;

Diagenetic forward modelling of beach sediments from the Colombian Caribbean Margin: controlling factors on reservoir properties.

2025-05-01
Víctor Hugo Márquez Ramírez , José María Jaramillo , Luca Caracciolo +7 more | Marine and Petroleum Geology

Latest Cretaceous to Cenozoic Exhumation Patterns in the Northern Andes From the Sedimentary Provenance Record on the Broken Retro‐Foreland Putumayo Basin

2025-05-01
Eduer Giovanny Nova Rodríguez , Maurício Parra , A. Cardona +4 more | Basin Research
ABSTRACT The topographic growth of the Eastern Cordillera in the northern Andes of Colombia is a critical event in the tectonic and paleogeographic evolution of the western Amazon Basin. Documentation … ABSTRACT The topographic growth of the Eastern Cordillera in the northern Andes of Colombia is a critical event in the tectonic and paleogeographic evolution of the western Amazon Basin. Documentation of early orogenic growth is enabled through multi‐proxy provenance signatures recorded in the adjacent retro‐foreland basin. In broken foreland basins, basement highs interrupt the lateral continuity of facies belts and potentially mask provenance signals. The Putumayo Basin is a broken foreland basin in western Amazonia at ~1°–3° N, where the Florencia, Macarena, and El Melón‐Vaupes basement highs have compartmentalised discrete depocentres during basin development. This study presents new evidence from stratigraphic, conglomerate clast count, sandstone petrography, detrital zircon U–Pb geochronology and novel apatite detrital U–Pb age trace element geochemistry analyses. The results show that the southern Eastern Cordillera (i.e., Garzon Massif) and Putumayo Basin basement highs were initially uplifted during the Late Cretaceous coeval with the Central Cordillera, most likely associated with the collision of the Caribbean Large Igneous Province (CLIP). Distinctive facies distributions and provenance changes characterise the Putumayo Basin over a ~300 km distance from south to north, in the Rumiyaco Formation and Neme Sandstone. Detrital zircon U–Pb ages record a sharp reversal from easterly derived Proterozoic to westerly sourced late Mesozoic–Cenozoic Andean zircons derived principally from the Central Cordillera. Provenance signatures of the synorogenic Eocene Pepino Formation demonstrate the continued exhumation of the Eastern Cordillera as a second‐order source area. However, the emergence of the northern intraplate highs modulated the provenance signature due to the rapid unroofing of relatively thinner marine sedimentary cover strata that overlie the Putumayo basement, in comparison to the thicker sequences of the southern basin. The provenance data and facies distributions of the Oligocene–Miocene Orito Group were more heterogeneous due to strike‐slip deformation, associated with major plate tectonic reorganisation as the Nazca Plate subducted under the South American margin.

Coalification patterns and thermal-depositional history of the Upper Cretaceous-Paleogene coal in the Eastern Cordillera Basin, Colombian Andes

2025-05-01
Juan Sebastian Gomez-Neita , Ana Maria Pimentel Mizusaki , Taís Freitas da Silva +7 more | Marine and Petroleum Geology

Lacustrine and paleontological records from the middle Norian of the Eastern Cordillera of Colombia: Paleoenvironmental and paleobiogeographic implications of western paleo-equatorial Pangea

2025-05-01
Carlos Maura Alarcón , Carina E. Colombi , Oscar F. Gallego +7 more

Quaternary uplift on the southeastern coast of Cuba

2025-05-01
Christine Authémayou , Leandro Peñalver , Denovan Chauveau +7 more

Links between pore system evolution, lake genesis and limnological characteristics: Evidence from basin morphology, specific conductivity and lake level variability on San Salvador Island, Bahamas

2025-05-01
Charles Breithaupt , Ronald Knoll , Jason Gulley +5 more
Abstract Lake‐aquifer connectivity in coastal carbonate platforms is governed by diagenetic and depositional processes which influence basin morphology. Because coastal aquifers are known to have tidally controlled water levels, tidal … Abstract Lake‐aquifer connectivity in coastal carbonate platforms is governed by diagenetic and depositional processes which influence basin morphology. Because coastal aquifers are known to have tidally controlled water levels, tidal fluctuations in lakes may be used to expand areal measurements of permeability and establish a link between regional‐scale connectivity and lake genesis. To evaluate the link between basin connectivity and genesis, we compared time series of water level fluctuations collected at high temporal resolution in the ocean and 24 lakes and ponds on San Salvador Island, Bahamas. By treating each lake as a well with a very large footprint, we calculated apparent hydraulic diffusivity and aquifer permeability of the rocks surrounding each lake to relative and regional‐scale connectivity of lakes to the ocean. We paired apparent permeabilities (10 −14.4 to 10 −9.8 m 2 ) with observations of basin morphologies derived from light detection and ranging (LIDAR) to identify five distinct lake types that reflect varying degrees of diagenesis of rocks separating lakes from the ocean: (1) Back beach flood basins formed due of sedimentation and sea‐level rise. Back beach flood basins that formed during the Holocene have the lowest apparent permeabilities (10 −14.4 m 2 ). (2) Cutoff lagoons, which sediments connect offshore cays, and plug tidal inlets resulting in isolated lakes. Cutoff lagoons which formed during the Holocene also have low apparent permeabilities (10 −13.9 to 10 −12.8 m 2 ). (3) Dune swale lakes formed when rising sea‐levels flooded topography created by previous sea‐level highstands and have apparent permeabilities of 10 −12.5 m 2 . Dune swale lakes have (4) karst lakes, which form when caves or touching vugs link lakebeds to the ocean have the highest apparent permeabilities of 10 −9.8 m 2 . (5) Overflow ponds, which receive water when high tides, cause neighbouring karst lakes to spill over a topographic divide. For lakes which do not exhibit any aquifer/ocean connectivity, we suggest low permeability exposure surfaces lining the lakebed drive hydraulic isolation.

Corrigendum to “Anomalous weathering trends indicate accelerated erosion of tropical basaltic landscapes during the Permo-Triassic warming” [Earth and Planetary Science Letters 577 (2022) 117256]

2025-05-01
Jianghai Yang , Peter A. Cawood , Daniel J. Condon +5 more

Study of lava dome growth and its partial destruction during September 2016 to February 2017 at Volcán de Colima, Mexico.

2025-05-01
Raúl Arámbula‐Mendoza , Rogelio de Jesús García-Flores , Nick Varley +4 more

Desastre social en Acapulco: El impacto del huracán Otis en Guerrero, México

2025-04-30
Irma Solano Díaz , Alejandro Díaz Garay , Beatriz S. Méndez +2 more | Arandu-UTIC.
El huracán Otis en cuestión de horas alcanzó categoría 5, la más intensa de la escala Saffir-Simpson, frente a las costas de Guerrero. El objetivo es comprender el impacto social, … El huracán Otis en cuestión de horas alcanzó categoría 5, la más intensa de la escala Saffir-Simpson, frente a las costas de Guerrero. El objetivo es comprender el impacto social, económico y emocional que ocasionó Otis en los hogares más desfavorecidos de la periferia de Acapulco. La investigación sigue una estrategia metodológica cualitativa, utilizando la técnica de la observación, que fue acompañada de toma de notas, fotografías, charlas informales; narrativas y una encuesta, a fin de comprender el significado que las personas tenían en su imaginario, respecto al huracán Otis. El trabajo de campo se realizó en dos ejidos: La Sabana y Cayaco, ambos son semiurbanos y pertenecen a la periferia de Acapulco. Los resultados revelan que las familias no estaban preparadas para enfrentar la magnitud del huracán Otis, siendo Acapulco un lugar con evidente riesgo ciclónico, además de la falta de información, se requiere aducción para estar informados, y los habitantes pudieran proteger sus bienes, la población de 18 a 60 años manifestó no haber vivido algo semejante. El miedo fue una de las emociones más recurrentes que externaron los encuestados, el 95% dijo haber experimentado miedo, aunado a ideas de muerte, de que les cayera la casa, que quedará destruida, inundada, que sería el fin del mundo. El ruido del viento y perder algún familiar también les provocó miedo. La naturaleza golpeó muy fuerte a todos los niveles de la sociedad, a ricos y pobres, pero con mayor intensidad a la población más desfavorecida del puerto.

Water production control in the C-lower reservoir, VLE-196 area, block V Lamar, Venezuela

2025-04-30
M. A. Díaz , Sadi Iturralde , Edison Brito +1 more
The VLE-196 area, located north of Block V Lamar in Maracaibo, Venezuela, encompasses Eocene reservoirs, especially the C-SUPERIOR and C-INFERIOR sands of the MISOA formation, with a particular focus on … The VLE-196 area, located north of Block V Lamar in Maracaibo, Venezuela, encompasses Eocene reservoirs, especially the C-SUPERIOR and C-INFERIOR sands of the MISOA formation, with a particular focus on the C-4/C-5 sands of C-INFERIOR. In recent years, water production in the 32 active wells has experienced a gradual increase, generating technical-economic problems that threaten oil recovery. The study was divided into four phases. The first consisted of the static and dynamic characterization of the reservoir. Subsequently, a well review was performed for a comprehensive analysis, which provided a diagnosis based on well characteristics and similarities/differences with neighboring wells. The final proposal included actions aimed at minimizing water production, improving sweep efficiency, extending well life, and reducing water treatment and disposal costs. Two pressure zones were identified, one to the north as a low-pressure zone and one to the south as a highpressure zone. Wells in the high-pressure zone exhibited coning primarily in C-5, while those in the lowpressure zone exhibited adedimentation in C-4 flow units. Differences in fluid behavior between C-4 and C-5 sands suggest considering these reservoirs as separate entities in future studies. The research seeks to address the current challenges through a comprehensive approach, offering solutions tailored to individual well characteristics to optimize production and mitigate water-related problems.

INFLUENCIA DEL TAMANO DE PARTICULA Y ANALISIS GEOTECNICO EN ESTABILIDAD DE TALUDES PARA CANALIZACIONES

2025-04-30
J. López | International Journal of Advanced Research
This article addresses a project located in the southern region of Guatemala City, specifically in Villanueva, aimed at protecting a new infrastructure intended for an industrial park. The initiative integrates … This article addresses a project located in the southern region of Guatemala City, specifically in Villanueva, aimed at protecting a new infrastructure intended for an industrial park. The initiative integrates hydraulic and geotechnical aspects, focusing on the stability and sustainability of gabion structures for managing flows from the Platanitos River and soil recovery. The impact of stone particle size and the application of polymeric coatings on the gabions was analyzed, using digital tools for hydraulic design and slope stability evaluation. The methodology included a detailed hydraulic analysis, followed by a slope stability design that considered safety factors and the interaction of water in the channel. A pseudo-static analysis was conducted to verify the structures resistance under dynamic conditions, highlighting the importance of evaluating stability in the presence of water. This technical-geotechnical approach allowed for the proper alignment of design requirements with ground conditions, ensuring the infrastructures resilience and durability.The study emphasizes the need to specify materials accurately and address multiple technical aspects to guarantee long-term sustainability, in harmony with the surrounding geotechnical and environmental context. The results underscore the relevance of integrating hydraulic and geotechnical analyses in the planning of channeling works, ensuring their functionality and stability under critical conditions.

¡Qué desastre!

2025-04-29

Status of the coral formations of Bajo Nuevo Reef Complex, Western Caribbean, Colombia

2025-04-28
Martha Catalina Gómez Cubillos , Carolina Z. Guerra , Nicolás Mendoza +1 more
Introduction: Although many reefs have been disturbed by the combined effects of climatic and non-climatic stressors, there still are regions largely free from direct human pressures such as runoff, pollution, … Introduction: Although many reefs have been disturbed by the combined effects of climatic and non-climatic stressors, there still are regions largely free from direct human pressures such as runoff, pollution, and maritime traffic due to their geographic remoteness. This suggests that they are replicas of “pristine reefs”, that allow the investigation of relationships between reef communities and their environment. Objective: To evaluate the status of the coral formations of Bajo Nuevo, Seaflower Biosphere Reserve. Methods: The coral health and the relative cover of reef-building organisms and of their main competitors were evaluated. In every station (11), ten photo quadrants of 0.25 m2 were evaluated along a 10 m tape measure combined, along with ~3 min videos. Results: 32 coral species were recorded, 30 of them Scleractinia and two of hydrocorals, with the highest richness in the reef lagoon. In 2021, the reefs in Bajo Nuevo were dominated by non-reef-building organisms (61.7 ± 0.10 %), the building species represented only 23.9 ± 0.10 %; 3.2 ± 0.03 % was coral skeleton with recent and transitional death less than 15 days old. Signs of diseases affected three genera, 13 species and 23.5 % of the colonies evaluated, of which 84.9 % showed one of the four signs related to the stony coral tissue loss disease. Conclusions: With previous expeditions (2010-2011) as a reference, this reef complex registered in 2021 a drop in the cover of hard corals and calcareous algae, and coral richness; an increase in the cover of non-reef-building organisms, with a high prevalence of signs of unhealthiness associated with different coral diseases. This confirms that these reefs are in danger (EN), as suggested by the red list of marine and coastal ecosystems of Colombia.

Conexión de flujos, zona de descarga y parámetros físicos de dos manantiales de la zona centro de Xalapa, Veracruz

2025-04-25
Carlos Manuel Lezama-Alcocer , Itzel Yolotzin Hernández-Portilla
En el municipio de Xalapa, Veracruz, se padecen serios problemas para satisfacer la demanda actual de agua, sin embargo existen múltiples manantiales abandonados, entre estos el Tecuanapan y el Casa … En el municipio de Xalapa, Veracruz, se padecen serios problemas para satisfacer la demanda actual de agua, sin embargo existen múltiples manantiales abandonados, entre estos el Tecuanapan y el Casa del Lago. Ubicados en la zona urbana central del municipio han sufrido modificaciones irreversibles en su entorno, lo que impiden conocer si tienen conexión directa entre sí, identificar sus zonas de descarga o determinar parámetros físicos. Abordar lo mencionado abona a resolver de mejor manera problemas que los aquejan, ante lo expuesto se emplea el método de trazador por dilución de sales, inspección en campo y determinación de parámetros físicos. Los resultados demuestra que no existe conexión directa entre sus flujos; la zona de descarga del Tecuanapan (~471 m de su afloramiento) se encuentra en la parte superior del túnel de confinamiento del río Carneros, y la del Casa del Lago (~40 m de su afloramiento) en una fuente ornamental y en un tubo cercano a esta. Al final ambos flujos terminan en los embalses artificiales de Los Lagos del Dique. El Tecuanapan (12.70 L/s) mostró un caudal cinco veces mayor al de Casa del Lago (2.67 L/s), en tanto este último valores de conductividad eléctrica y sólidos disueltos más altos, así como temperatura ligeramente más baja. La información obtenida ayuda a conocer aspectos hidrológicos básicos pero de suma importancia, es un primer paso en la búsqueda de considerarlos fuentes complementarias ante la demanda actual de agua en el municipio.

Late Eocene Lu–Hf ages on Carayaca (Puerto Cabello) eclogites: reconstructing the history of the Cordillera de la Costa Central, northern Venezuela

2025-04-18
James Pindell , Walter V. Maresch , Franco Urbani Patat +5 more
We present the first Lu–Hf dating on HP/UHP mineral assemblages in eclogitic rocks from Puerto Cabello, northern central Venezuela. The rocks characterise the Carayaca terrane of the Cordillera de la … We present the first Lu–Hf dating on HP/UHP mineral assemblages in eclogitic rocks from Puerto Cabello, northern central Venezuela. The rocks characterise the Carayaca terrane of the Cordillera de la Costa (CdlC) along the coast and faults bounding the valley of Caracas City. The new late Eocene peak metamorphic ages (38–36 Ma) pertain to Eocene subduction of Proto-Caribbean crust to 80–100 km depth beneath the Caribbean forearc as the latter collided with Venezuela. The ages break the formerly assumed correlation with Margarita Island eclogites and Villa de Cura blueschists of southern CdlC. The distinct histories of these HP/LT metamorphic suites and the Etpana terrane in Guajira, Colombia, constrain depth geometries in regional evolutionary models. By integrating our results with an updated view of synorogenic sedimentation in the Piemontine belt, southern CdlC, we propose crustal scale present and evolutionary cross sections and maps for the development and exhumation history of the Carayaca terrane and the greater CdlC. In addition, this synthesis concludes that Caribbean collision was preceded by Palaeocene incipient subduction and rift fault inversion along Venezuela's Proto-Caribbean margin, exposing Caucagua–El Tinaco belt basement to erosion as recorded in Los Cajones Formation flysch of the Piemontine belt.

Fluids from deep subducted sediments control the seismic behavior of the Lesser Antilles megathrust

2025-04-17
Yaocen Pan , Nathalie Feuillet , C. Prigent +3 more