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Abstract: Evaluation of the Three-Dimensional Structure of the Cordillera Oriental of Colombia

Dept. Geological Sciences, University of Tennessee, Knoxville, TN;
Department of Geological Sciences, University of Tennessee, Knoxville, TN 37996; and 'Environmental Sciences Division, Bldg. 1509, MS-6400, Oak Ridge National Laboratory, Box 2008, Oak Ridge, TN 37831

Kinematic plate tectonic reconstructions predict that the Cordillera Oriental of Colombia experienced oblique convergence throughout the Cenozoic. Even though oblique convergence along plate boundaries is usually partitioned between transcurrent and contractional components of deformation, kinematic reconstructions of the Cordillera ignore deformation along the strike. Instead, a doubly vergent, fold-thrust geometry has been suggested for the Cordillera, and about 100 km of NW-SE horizontal shortening has been estimated using standard two-dimensional reconstruction techniques. Therefore, current reconstructions (in map and cross section view) can only assume deformation paths perpendicular to the trend of the Cordillera (NW-SE dip-slip). This introduces significant errors and distortions in estimates of horizontal shortening, hydrocarbon maturation and migration histories, and basin reconstructions. The main goal of this project is to better understand the 3D structure and kinematics of the Cordillera Oriental. The significance of this study is to provide the first estimate of deformation partition in this region, therefore improving the construction of restored cross-sections, palinspastic maps and paleogeographic reconstructions. A three-dimensional kinematic model of part of the Cordillera Oriental will be built using detailed field mapping, available subsurface information, and remote sensing. This local three-dimensional model will account for deformation along and across strike, and can be used to extrapolate the results to regional studies. Detailed field mapping will focus on structures thought to accommodate NW-SE horizontal shortening, and computer-aided remote sensing, reconstruction, and three-dimensional visualization will be used to build and test the kinematic model of the Cordillera. Collection of new, detailed field information will be at the core of this project, and will include detailed field mapping of approximately 400 km{2}, collection of mesoscopic strain data, and observation of structural style and crosscutting relationships (stratigraphic and tectonic).

AAPG Search and Discovery Article #90931©1998 AAPG Foundation Grants-in-Aid