T169 Detrital Zircons on the North American Continental Interior (Posters)

Monday, 26 September 2016
9:00 AM - 6:30 PM
Exhibit Hall E/F

REGIONAL SEDIMENT PROVENANCE AND BASIN DEVELOPMENT ALONG THE SOUTHERN NORTH AMERICAN CONTINENTAL MARGIN OVER GEOLOGIC TIME SCALES: DETRITAL ZIRCON GEOCHRONOLOGY OF WEST TEXAS

Paper number: T169-3
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

The Appalachian and Cordilleran orogenic belts and their related sedimentary basins intersect in the Big Bend region of west Texas. The strata representing these major orogenic belts are exposed within a long-lived continental margin that records several cycles of tectonism, basin development, volcanism, and climate change. The primary objective of this study is to understand the various stages of geologic development of the southern continental margin of North America utilizing detrital zircon geochronology to interpret spatial and temporal changes in sediment sources over time. Recent studies utilizing detrital zircons suggest that continental-scale sediment dispersal systems represent a complex interplay between Appalachian and Cordilleran sources of sediment. Exploring this concept, samples from Precambrian strata exposed near Van Horn, Paleozoic rocks in the Marathon thrust belt, and Mesozoic to Cenozoic rocks in Big Bend National Park were analyzed by U-Pb detrital zircon geochronology. Based on U-Pb detrital zircon probability curves and peak age populations, changes in detrital zircon age populations between the Paleozoic and Mesozoic strata reflect a change from dominantly Appalachian/Ouachita orogeny sourced sediment (Precambrian (PC) 89%; Paleozoic (PZ) 11%; Mesozoic (MZ) 0%; Cenozoic (CZ) 0%) to Cordilleran derived sediment (PC 23%; PZ 11%; MZ 60%; CZ 6%). Changes in Mesozoic to Cenozoic strata record the transition from sediment derived from Laramide/Cordilleran sources to more local Basin and Range sediment sources (PC 32%; PZ 9%; MZ 26%; CZ 33%). Comparison of U-Pb detrital zircon ages of the strata of west Texas with known ages of basement and igneous provinces allow us to reconstruct sediment provenance, recycling of sediment between the major orogenic belts, and the timing of various stages of deformation and basin development along the southern North American continental margin.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-279758

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