37 Cordilleran Margin Evolution and Supercontinent Tectonics: From Pangea Assembly to North American Orogenesis (Posters)

This session integrates tectonics, petrology, geochronology, stratigraphy, and paleontology to illuminate how Paleo-Pacific plates drove subduction dynamics, crustal evolution, and paleogeographic reconstructions across the complex geological architecture of the American Cordilleras.

Friday, 24 April 2026
8:00 AM - 5:30 PM
LMH, 5th Floor Chapel

Deciphering provenance signals from recycled sedimentary and mafic sources: Implications for polyphasic deformation in the Northern Andes.

Paper number: 37-13
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Andean-type orogens are defined by contractional episodes that drive major basement exhumation and the accretion of exotic oceanic terranes. Reconstructing past source areas using standard methods, such as detrital zircon U-Pb geochronology, is often complicated due to sedimentary recycling during basement exhumation and the presence of zircon-poor mafic source areas. In the Northern Andes, alternating contractional phases from the Late Cretaceous to the Miocene promoted both the recycling of older strata during basement exhumation and the accretion of allochthonous oceanic crust. Sedimentary reworking and the erosion of mafic basements remain poorly identified in the detrital and sedimentary record of the Northern Andes.

The Central and Western cordilleras of Colombia exhibit distinct basement compositions. The Central Cordillera is mostly characterized by pre-Cretaceous crystalline rock with continental margin affinity, while the Western Cordillera features oceanic igneous rocks accreted during the Late Cretaceous. These mountain belts, along with the Cauca intermontane basin, preserve a sedimentary record of the Cretaceous–Paleogene tectonic evolution of the Colombian Andes. We integrate new sandstone petrography, detrital zircon U-Pb geochronology, and zircon Hf isotopes from understudied Cretaceous to Paleogene units. To overcome the limitations of zircon fertility in the mafic basement of the Western Cordillera and the Cauca Basin, available zircon U-Pb data will be combined with whole-rock geochemistry of fine-grained Cretaceous to Miocene rocks. By integrating these results with regional datasets, we refine the Paleogene paleogeography of the Northern Andes and demonstrate the impact of intense sedimentary reworking during the unroofing of the Central and Western Cordilleras. This research was supported by project 047-2025, funded by ANH-Minciencias.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3

doi: 10.1130/abs/2026CD-411043

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