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  • 1
    Publication Date: 2017-06-10
    Description: The Lower Cretaceous units of the Eastern Cordillera of Colombia have been deposited during a stage when the area where nowadays lies a contractional orogen was an actively deforming rift. Therefore, they are syn-rift sedimentary units. These rocks have a unique feature in the Cretaceous sedimentary column of this mountain chain. This is a widespread planar fabric expressed mostly as a penetrative slaty cleavage. This planar fabric is only macroscopically evident in Cretaceous units older than Barremian. Planar fabric (e.g. slaty cleavage) is one of the products of internal or penetrative deformation (i.e. contractional deformation at microscopical scale in rock units). Pressure solution and even cleavage have been recently reported in areas undergoing only subtle burials (Engelder & Marschak 1985). However, in the Eastern Cordillera, the units where planar fabric is evident are the base of a sequence of at least 5km and they have vitrinite reflectance values up to 2. These data and the formation of clorithoid contemporary with the slaty cleavage, allow us to propose that this planar fabric was developed when the Lower Cretaceous units had an amount of overburden close to the thickness of the entire Cretaceous sequence...
    Description: conference
    Keywords: VAE 400 ; VAE 130 ; VEX 700 ; VEX 100 ; VQC 000 ; Tektogenese {Geologie} ; Geomechanik ; Kolumbien {Geologie} ; Anden {Geologie} ; Lagerstättengenese ; Kolumbien ; Anden ; Orogenese ; Deformation 〈Geologie〉 ; Hydrothermale Lösung ; Mineralisation ; Hydrothermale Lagerstätte
    Language: German
    Type: anthologyArticle , publishedVersion
    Format: application/pdf
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  • 2
    Publication Date: 2012-02-01
    Description: Low-temperature thermochronometry and crosscutting relationships identified in newly released reflection seismic data reveal a previously unrecognized zone of early Andean shortening in Colombia. Apatite fission-track data and thermal modeling help define a 60–50 Ma onset of rapid exhumation along the present boundary between the Magdalena Valley hinterland basin and Eastern Cordillera thrust belt. Subsurface angular unconformities localized above fold-thrust structures indicate Paleogene deposition in a wedge-top depozone containing doubly vergent reverse faults. Retrodeformation of a cross section based on interpreted seismic profiles and thermochronometric data indicates Paleocene to Early Eocene shortening and exhumation occurred through simultaneous activation of east- and west-directed reverse faults across a broad orogenic front. Subsequent deformation focused along west-directed inversion structures. These relationships reveal that deformation operated in a disparate manner, rather than following a systematic progression from hinterland to foreland. The northern Andes also exemplify the potential effects of hinterland sediment loading and fault strength on deformation advance in contractional orogens.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
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  • 3
    Publication Date: 2012-01-01
    Description: Sedimentological, provenance, and detrital thermochronological results for basin fill at the modern deformation front of the northern Andes (6°N latitude) provide a long-term, Eocene to Pliocene record of foreland-basin sedimentation along the Eastern Cordillera–Llanos basin boundary in Colombia. Lithofacies assemblages and paleocurrent orientations in the upward-coarsening, ~5-km-thick succession of the Nunchía syncline reveal a systematic shift from craton-derived, shallow-marine distal foreland (back-bulge) accumulation in the Mirador Formation, to orogen-sourced, deltaic, and coastal-influenced sedimentation of the distal to medial foreland (foredeep) in the Carbonera and León Formations, to anastomosing fluvial and distributive braided fluvial megafan systems of the proximal foreland (foredeep to wedge-top) basin in the lower and upper Guayabo Formation. These changes in depositional processes and sediment dispersal are supported by up-section variations in detrital zircon U-Pb and (U-Th)/He ages that record exhumation of evolving, compartmentalized sediment source areas in the Eastern Cordillera. The data are interpreted in terms of a progressive eastward advance in fold-and-thrust deformation, with late Eocene–Oligocene deformation in the axial zone of the Eastern Cordillera along the western edge of Floresta basin (Soapaga thrust), early Miocene reactivation (inversion) of the eastern margin of the Mesozoic rift system (Pajarito and Guaicaramo thrusts), and middle–late Miocene propagation of a footwall shortcut fault (Yopal thrust) that created the Nunchía syncline in a wedge-top (piggyback) setting of the eastern foothills along the transition from the Eastern Cordillera to Llanos foreland basin. Collectively, the data presented here for the frontal Eastern Cordillera define a general in-sequence pattern of eastward-advancing fold-and-thrust deformation during Cenozoic east-west shortening in the Colombian Andes.
    Print ISSN: 0016-7606
    Electronic ISSN: 1943-2674
    Topics: Geosciences
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  • 4
    Publication Date: 2015-08-01
    Description: In this paper, we demonstrate a workflow for constructing kinematic restorations in complex foothill areas devoid of growth strata and other indicators for the chronology of deformation. Our initial reconstructions utilize thermochronometric data, a well-documented structural geometry, and a first-order conversion of exhumation rates into tectonic rates. We then utilize models obtained from the new in-house–developed software FetKin to build a first version of the thermokinematic restoration. The FetKin approach is geared primarily toward testing and further calibration and refinement of the kinematic restoration, based on the extent to which the model result agrees with thermochronometric data from the study area in the form of both discrete ages and inverse-modeled time–temperature envelopes. This analysis also provides rates of shortening and time–temperature paths throughout the model space that can be used to make first-order predictions of when different source rocks entered the oil window. These capabilities are demonstrated in a pilot case study along a cross section in the Colombian Eastern Cordillera. The improved confidence in the reconstruction that this technique provides allows us to show increasing shortening rates in this part of the Andes during the Neogene reaching up to 5 mm/yr (0.20 in./yr) by the Pliocene, and constrain the timing of generation from the most important oil kitchens for the Eastern Cordillera-Llanos basin petroleum system. This approach, therefore, proves to be a useful method for creating high-resolution and high-fidelity kinematic restorations.
    Print ISSN: 0149-1423
    Electronic ISSN: 1943-2674
    Topics: Geosciences
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  • 5
    Publication Date: 2010-10-01
    Description: Previously unreleased fission-track results and regional structural relationships are used to interpret the migration of deformation during Cenozoic orogenesis in the Eastern Cordillera (Cordillera Oriental) of the Colombian Andes. Low-temperature thermochronological results are based on apatite and zircon fission-track analyses of 41 samples collected along vertical and horizontal transects across the Eastern Cordillera at 4–7°N latitude. Inverse modeling of fission-track results helps delimit the most probable cooling histories caused by exhumation linked to upper-crustal deformation. These inverse models are constrained by known structural geometries, chronostratigraphy, biostratigraphy, and vitrinite reflectance data. Fission-track data and modeling results indicate a close correspondence in the timing and style of deformation along the western and eastern flanks of the Eastern Cordillera. East-directed fold-thrust deformation along the eastern boundary with the Llanos foreland basin was underway by the late Oligocene and early Miocene. Similarly, west-directed fold-thrust structures along the western boundary with the intermontane middle Magdalena Valley Basin became active at approximately the same time. Less well known is the time of initial shortening within the axial segment of the Eastern Cordillera; although fission-track results suggest active exhumation by the early Miocene, shortening may have commenced much earlier during the late Eocene. Timing relationships for the Eastern Cordillera have important implications for the generation, migration, and accumulation of petroleum in the middle Magdalena Valley intermontane basin and the Llanos foreland basin. Our study provides a regional context to assess the timing of structural trap development and improve exploration and development of new and existing reservoirs in Colombia and analogous fold-thrust systems elsewhere. Andrés Mora is a senior researcher and leader of the Cronologia de la deformaciòn en las Cuencas Subandinas research project at Ecopetrol-Instituto Colombiano del Petróleo. He received his B.Sc. degree in geology from the Universidad Nacional de Colombia in 1999 and his Ph.D. from the Institut für Geowissenschaften, Universität Potsdam (summa cum laude) in 2007. His research interests include structural geology, thermochronology, and basin analysis. Brian Horton is an associate professor at the Department of Geological Sciences and Institute for Geophysics in the Jackson School of Geosciences at the University of Texas at Austin. He received his B.S. degree in geology from the University of New Mexico (1992), his M.S. degree in earth sciences from Montana State University (1994), and his Ph.D. in geosciences from the University of Arizona (1998). His research interests include basin analysis, tectonics, and clastic sedimentology. Andrés Mesa is an exploration geologist who worked in Hocol S.A. from 2005 to 2009 and was in charge of an exploration and production contract in the Eastern Cordillera Basin. He received his B.Sc. degree in geology from the National University at Bogotá (Colombia) in 2005 and is currently doing an M.Sc. degree at Royal Holloway-University of London. His principal interest is basin analysis. Jorge Rubiano is a senior geologist at Ecopetrol-Instituto Colombiano del Petróleo. He obtained a B.Sc. degree from the National University at Bogotá (Colombia) and an M.Sc. degree in basin analysis from the University of South Carolina. Over the past years, he has worked for Ecopetrol on research projects addressing the stratigraphy, structure, basin evolution, and hydrocarbon systems of sedimentary basins in the northern Andes. Richard Ketcham is an associate professor of geological sciences at the University of Texas at Austin. He received his B.A. degree in geology and computer science from Williams College in 1987 and his Ph.D. in geological sciences from the University of Texas at Austin in 1995. His active research interests include thermochronology and geological applications of high-resolution x-ray computed tomography. Mauricio Parra graduated in geology from the National University of Colombia at Bogota in 2000 and received a Ph.D. in geosciences from Potsdam University (Germany) in 2009. He has worked in the tectonic evolution of the Colombian Andes and the associated foreland basin system using low-temperature thermochronometry and basin analysis. He is now a postdoctoral researcher at the Jackson School of Geosciences, University of Texas at Austin. Vladimir Blanco is the current leader of the organic geochemistry lab at Ecopetrol-Instituto Colombiano del Petróleo. He received his B.Sc. degree in geology from the Universidad Industrial de Santander at Bucaramanga (Colombia). He has worked on multiple projects from Ecopetrol since 2006 by giving technical support in basin modeling and characterization of source rocks and crude oils. Diego Garcia joined Ecopetrol-Instituto Colombiano del Petróleo (ICP) in 1998. He holds a diploma in geology from the National University at Bogotá (Colombia), an M.Sc. degree from the Institut Français du Pétrole School (France) on basin analysis, and a Ph.D. from the Federal University of Rio de Janeiro on petroleum and gas exploration. Currently, he is the technical leader of the geological research program of ICP. His research interests include the prediction of petroleum composition, thermal modeling, and the geological controls on petroleum migrations. Daniel Stockli is an associate professor in tectonics and thermochronometry at the University of Kansas and has been the director of the KU (U-Th)/He thermochronometry laboratory since 2001. He received his diploma in geology from the Eidgenössische Technische Hochschule Zürich in 1995 and his Ph.D. from Stanford University in 1999. His interests include continental tectonics, geo- and thermochronology, structural geology, and isotope geochemistry.
    Print ISSN: 0149-1423
    Electronic ISSN: 1943-2674
    Topics: Geosciences
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  • 6
    Publication Date: 2015-08-01
    Description: New biostratigraphic zonations, core descriptions, sandstone petrography, facies analysis, and seismic information are compared with published detrital and bedrock geo- and thermochronology to build a Cenozoic paleogeographic reconstruction of the Andean retroarc region of Colombia, encompassing the ancestral Central Cordillera, Middle Magdalena Valley, Eastern Cordillera, and Llanos basin. We identify uplifted sediment source areas, provenance domains, depositional environments, and thickness changes to propose a refined paleogeographic evolution of eastern Colombia. We conclude that Cenozoic evolution of the northernmost Andes includes (1) a period of contractional deformation focused in the Central Cordillera and Middle Magdalena Valley that may have started by the Late Cretaceous, although thermochronological data points to maximum shortening and exhumation during the late Paleocene; (2) a period of slower deformation rates or even tectonic quiescence during the middle Eocene; and (3) a renewed phase of contractional deformation from the late Eocene to the Pleistocene/Holocene expressed in provenance, bedrock thermochronology, and increased subsidence rates in the Llanos foreland. The sedimentary response in the Llanos foreland basin is controlled by source area proximity, exhumation and shortening rates, relationships between accommodation and sediment supply, as well as potential paleoclimate forcing. This new reconstruction changes the picture of Cenozoic basin evolution offered by previous reconstructions, providing an updated chronology of deformation, which is tied to a more precise understanding of basin evolution.
    Print ISSN: 0149-1423
    Electronic ISSN: 1943-2674
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  • 7
    Publication Date: 2015-08-01
    Description: FETKIN is a C++ program for forward modeling thermochronological ages on a two-dimensional geological cross section. Modeled ages for various thermochronometers are computed from time-temperature histories that result from coupling the modeled kinematics of deformation obtained from commercial software for balanced reconstructions (2DMove) and a Finite Element (FEM) computation of temperatures. Additional capabilities include the ability to accommodate: a) A smooth change of topological relief; b) The influence of variation in rock physical properties; and c) Multi-kinetic modeling of fission-track ages and length distributions, as well as apatite and zircon (U-Th)/He, and muscovite 40Ar/39Ar systems. A joint first order analysis of the impact of erosion parameters and material properties improves age predictions and allows for a more complete analysis of observed cooling ages based on their modeled thermal histories.Thus, this paper presents a new software tool that has been developed as a basic support for the methodological approach used to build the kinematic restorations shown in this volume, which are the basic input for petroleum systems modelling and prediction in the Colombian Eastern Cordillera and Llanos foothills basin.
    Print ISSN: 0149-1423
    Electronic ISSN: 1943-2674
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  • 8
  • 9
    Publication Date: 2009-02-01
    Description: Lower Cretaceous early syn-rift facies along the eastern flank of the Eastern Cordillera of Colombia, their provenance, and structural context, reveal the complex interactions between Cretaceous extension, spatio-temporal trends in associated sedimentation, and subsequent inversion of the Cretaceous Guatiquía paleo-rift. South of 4°30′N lat, early syn-rift alluvial sequences in former extensional footwall areas were contemporaneous with fan-delta deposits in shallow marine environments in adjacent hanging-wall areas. In general, footwall erosion was more pronounced in the southern part of the paleorift. In contrast, early syn-rift sequences in former footwall areas in the northern rift sectors mainly comprise shallow marine supratidal sabkha to intertidal strata, whereas hanging-wall units display rapid transitions to open-sea shales. In comparison with the southern paleo-rift sector, fan-delta deposits in the north are scarce, and provenance suggests negligible footwall erosion. The southern graben segment had longer, and less numerous normal faults, whereas the northern graben segment was characterized by shorter, rectilinear faults. To the east, the graben system was bounded by major basin-margin faults with protracted activity and greater throw as compared with intrabasinal faults to the west. Intrabasinal structures grew through segment linkage and probably interacted kinematically with basin-margin faults. Basin-margin faults constitute a coherent fault system that was conditioned by pre-existing basement fabrics. Structural mapping, analysis of present-day topography, and balanced cross sections indicate that positive inversion of extensional structures was focused along basin-bounding faults, whereas intrabasinal faults remained unaffected and were passively transported by motion along the basin-bounding faults. Thus, zones of maximum subsidence in extension accommodated maximum elevation in contraction, and former topographic highs remained as elevated areas. This documents the role of basin-bounding faults as multiphased, long-lived features conditioned by basement discontinuities. Inversion of basin-bounding faults was more efficient in the southern than in the northern graben segment, possibly documenting the inheritance and pivotal role of fault-displacement gradients. Our observations highlight similarities between inversion features in orogenic belts and intra-plate basins, emphasizing the importance of the observed phenomena as predictive tools in the spatiotemporal analysis of inversion histories in orogens, as well as in hydrocarbon and mineral deposits exploration. © Journal compilation © 2009 Blackwell Publishing Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.
    Print ISSN: 0950-091X
    Electronic ISSN: 1365-2117
    Topics: Geosciences
    Published by Wiley
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  • 10
    Publication Date: 2010-02-01
    Description: In order to evaluate the relationship between thrust loading and sedimentary facies evolution, we analyse the progradation of fluvial coarse-grained deposits in the retroarc foreland basin system of the northern Andes of Colombia. We compare the observed sedimentary facies distribution with the calculated one-dimensional (1D) Eocene to Quaternary sediment-accumulation rates in the Medina wedge-top basin and with a three-dimensional (3D) sedimentary budget based on the interpretation of ~1800 km of industry-style seismic reflection profiles and borehole data. Age constraints are derived from a new chronostratigraphic framework based on extensive fossil palynological assemblages. The sedimentological data from the Medina Basin reveal rapid accumulation of fluvial and lacustrine sediments at rates of up to ~500 m my-1 during the Miocene. Provenance data based on gravel petrography and paleocurrents reveal that these Miocene fluvial systems were sourced from Upper Cretaceous and Paleocene sedimentary units exposed to the west in the Eastern Cordillera. Peak sediment-accumulation rates in the upper Carbonera Formation and the Guayabo Group occur during episodes of coarse-grained facies progradation in the early and late Miocene proximal foredeep. We interpret this positive correlation between sediment accumulation and gravel deposition as the direct consequence of thrust activity along the Servitá-Lengupá faults. This contrasts with one class of models relating gravel progradation in more distal portions of foreland basin systems to episodes of tectonic quiescence. © 2010 The Authors. Basin Research © 2010 Blackwell Publishing Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.
    Print ISSN: 0950-091X
    Electronic ISSN: 1365-2117
    Topics: Geosciences
    Published by Wiley
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