Award Date

12-1-2022

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Geoscience

First Committee Member

Tomas Capaldi

Second Committee Member

Michael Wells

Third Committee Member

Kevin Konrad

Fourth Committee Member

Carlos Dimas

Abstract

The Bermejo retroarc foreland basin system formed in flexural response to Miocene crustal thickening in the Andean orogenic system, specifically, the eastward propagation of the Precordillera fold-thrust belt and the basement-involved uplift of the Sierras Pampeanas. Previous work in the area has mainly focused on the mechanisms and expression of flat slab subduction and the structural geometry of the basement-involved Sierras Pampeanas and east-vergent Precordillera fold-thrust belt at depth. Much of this work has furthered the understanding of Bermejo basin evolution north of 31ºS, however debate still exists whether the N-S trending Bermejo basin evolved synchronously or asynchronously through time. An in-depth, along-strike analysis of the Bermejo basin is required to determine whether or not the basin evolved synchronously. Our study seeks to constrain the along-strike Neogene tectonics of the Eastern Precordillera via well exposed Bermejo basin deposits through integration of new stratigraphic, detrital zircon U-Pb geochronology provenance, and detrital apatite low temperature thermochronology datasets from southern Bermejo basin. New data from twomudstones, siltstones and sandstones that transition into fluvial-alluvial fan conglomerate facies tracking the eastward migration of deformation. New detrital apatite thermochronology ages from the base of the measured sections record a mean age of ca. 6 Ma, suggesting two temporally distinct deformation events along-strike of the Bermejo basin. When we compare our new data with published data from northern Bermejo, we observe a north to south: (1) decrease in stratigraphic thicknesses, and (2) increase in exhumation ages along strike. This study utilizes newly collected data in comparison with published data to constrain along-strike variability of Precordillera thrust-front evolution and Bermejo basin development.

Keywords

broken foreland basin; detrital geochronology; detrital thermochronology; Sierras Pampeanas

Disciplines

Geology | Sedimentology

File Format

pdf

File Size

10200 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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