4 Sedimentary Systems and Provenance in the Western Cordillera
This session invites contributions on sedimentary processes, depositional environments, stratigraphic frameworks, and provenance evolution across western North America. Topics may include basin analysis, source-to-sink studies, and applications of stratigraphy to energy and environmental questions.
Wednesday, 22 April 2026
8:00 AM - 12:00 PM
LMH, Fiesta Terrace Salon
Regional Detrital Zircon Analysis of Synorogenic Basins Explains the Multi-Phase Development of the Central Andean Foreland Basin and Emergence of the Eastern Cordillera.
Paper number: 4-4
Program: Technical Sessions
Time: 9:05 AM – 9:25 AM
Authors
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Samuel Shekut Presenting AuthorUniversity of British Columbia, Earth, Ocean and Atmospheric Sciences, Vancouver, BC
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Joel SaylorUniversity of British Columbia, Vancouver, BC
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Paola AlvarezUniversity of British Columbia, Vancouver, BC
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Muhammad RafeezaUniversity of Calgary, Calgary, AB
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Oceane HorvathUniversity of British Columbia, Vancouver, BC
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Ruben JallazaLa Universidad Mayor de San Andrés, La Paz, La Paz
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Carlos SaulUniversidad Nacional de San Antonio Abad del Cusco, Cusco, Cusco
Abstract
The central Andes of Bolivia and Peru provide a uniquely challenging setting for provenance analysis as the continual eastward propagation of deformation throughout the period of orogenesis has remobilized sediment deposits which obfuscate the detrital zircon (DZ) signatures of characteristic source regions. Existing studies using provenance analysis, thermochronology, or stable isotope paleoaltimetry yield different estimates for the timing of orogenic events including initial uplift of the Western and Eastern cordilleras, the timing of uplift in the Altiplano or existence of hinterland paleotopography, and the formation of a foreland basin. We compile existing DZ datasets and report 8452 new DZ ages from synorogenic basins spanning the Late Cretaceous through Pliocene. Using non-negative matrix factorization and multidimensional scaling, we identify 8 characteristic DZ signatures which correspond to drainage of the Andean volcanic arc, the Western Cordillera, the Altiplano, the Mitu Group, the Eastern Cordillera, the Inter- and Subandean zones, and the San Ignacio Terrane. We use Monte-Carlo forward mixture modeling to track the sediment contribution from these sources to synorogenic basins. We consider geographic relationships and identify mixing patterns in DZ spectra that allow us to distinguish sediment recycling from primary drainage of source regions. These data provide insights into the along-strike differences in the timing of orogenic events, and track the Late Cretaceous through Eocene assemblage of the Western Cordillera and migration of a flexural forebulge through the proto-foreland, the Eocene and Oligocene emergence of the Eastern Cordillera and the formation of the modern foreland basin through the Oligocene and Miocene.
Geological Society of America Abstracts with Programs. Vol. 58, No. 3
doi: 10.1130/abs/2026CD-411033
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