Sedimentary basin evolution and structural compartmentalization in the northernmost Andes : Eastern Cordillera and Magdalena Valley, Colombia

Topographic development of the northernmost Andes is recorded in Mesozoic to Cenozoic clastic basin fill along the Middle Magdalena Valley (MMV) and Eastern Cordillera (EC) fold-thrust belt of Colombia. The Volador study area (5.5-6.0 °N) displays structures that pre-date and post-date an Eocene regional unconformity. The contrasting sedimentary successions above and below the unconformity define a major shift from organic-rich clastic marine deposition of regional extent to more localized coarse-grained fluvial and alluvial fan deposition with significant lateral variations. New detrital zircon U-Pb geochronological data across the unconformity reveals stepwise provenance changes in response to the transition from post-extensional (thermal) to foreland basin (flexural) subsidence. The latest Cretaceous to late Eocene shift from Andean basement and cratonic sources (eastern provenance) to principally Andean forearc and magmatic arc sources (western provenance) indicate the onset of shortening and basin segmentation. These phases of basin reorganization are associated with exhumation of the Western Cordillera (WC) and igneous activity in the Central Cordillera (CC) magmatic arc during initial Andean uplift. Vitrinite reflectance (VR) results indicate variations in topography and sediment burial across fault-bounded Cretaceous-Paleocene units after fault-related folding, as well as before and during unconformity development. The maximum depositional age (MDA) values from U-Pb data for stratigraphic units across the unconformity indicate a ca. 10 Myr hiatus of early to middle Eocene age. The MDAs provide constraints for timing and structural modeling of shortening and basin reorganization during the initial uplift in the Eastern Cordillera. Integration of detrital zircon U-Pb geochronology and VR data with structural and stratigraphic evidence indicates Mesozoic extension and post-extensional subsidence followed by early Cenozoic basin inversion during early Andean orogenesis. This study helps assess the kinematic sequence of deformation to identify linkages between uplift and sediment dispersal across the Middle Magdalena Valley, and the flanking Eastern Cordillera and Central Cordillera during Andean topographic development with attention to the role of stratigraphic and structural inheritance.

Name thesis:degree_name

Master of Science in Geological Sciences

Level thesis:degree_level

MASTERS

Discipline thesis:degree_discipline

Geological Sciences

Grantor

The University of Texas at Austin

Year dc:date.issued

2025

Author dc:creator

• Konguthaithip, Natthakorn

Advisor dc:contributor.advisor

• Horton, Brian K., 1970-

Committee members dc:contributor.committeemember

• Mauricio Parra
• Richard A. Ketcham

• Andes
• Colombia
• Basin
• Tectonics
• Foreland

Language dc:language.iso

English

Identifier URI

https://doi.org/10.26153/tsw/64212

OAI identifier oai:identifier

oai:repositories.lib.utexas.edu:2152/136910