T165 Structural Geology and Tectonics Division 40th Anniversary Symposium: Drivers of Orogenesis (Posters)

Tuesday, 12 October 2021
10:30 AM - 12:00 PM
Portland Ballroom 257 (Hybrid Room)

RELIEF CONSTRUCTION AND DESTRUCTION CONSTRAINED BY 3D THERMO-KINEMATIC MODELING: TECTONIC EVOLUTION OF THE ANTIOQUIA ALTIPLANO IN THE NORTHERN ANDES

Paper number: T165-8
Program: Technical Sessions
Time: 12:30 PM – 12:45 PM

Authors

Abstract

Construction and destruction of relief are a result of the interactions between climate and tectonics. The Antioquia Altiplano province (AAP) in the Colombian Andes is characterized by a ~2000 km2 scarcely understand regional paleosurface carved on top of the pre-Cenozoic crystalline rocks. This province has been interpreted as a result of episodic Cretaceous to Cenozoic compression and thick-skin deformation. At the end of the Paleocene, the northern Andes experienced a period of intense hot and humid climate; however, the impact of climatically driven erosion in the relief evolution of the Northern Andes has not been considered yet. In the absence of Cenozoic volcanic and clastic strata in the AAP, thermochronological data, the stratigraphic record of the adjacent basins, and mountain belt morphology are key to understand the long-term topographic and tectonic evolution of this geological province. Field data such as unconformities and cross-cut relations, provenance data, and coarsening-up sedimentary successions suggest at least two main pulses of deformation and topographic growth; the first between the Late Cretaceous and Paleocene during the collision of the Caribbean plateau and a final event during the Late Miocene. Low-temperature geochronological data spans between the Late Cretaceous and the Oligocene; this data has motivated several authors to propose additional Eocene to Oligocene deformation and exhumation events. We have performed a 3D thermo-kinematic modeling using the Pecube software, this model incorporates multiple geological temporal constraints to extracts information about past topography and exhumation. Results suggest Late Cretaceous to Paleocene topographic growth and high exhumation rates during the collision between the Caribbean Plateau and the continental margin. This event formed a higher topography compared to modern elevations. After the collision, the reduction of tectonic activity caused post-orogenic thermal relaxation that drove regional bedrock cooling. Tectonic quiescence and climatically driven erosion significantly reduced relief and promoted the formation of low-relief surfaces between the late Paleocene and Oligocene. During the last stage, deformation and inefficient erosion resulted in a phase of Miocene topographic growth and low exhumation that preserved and deformed the previously formed low-relief surfaces.

Geological Society of America Abstracts with Programs. Vol. 53, No. 6

doi: 10.1130/abs/2021AM-367783

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