T40 Influence of the Evolving Ouachita–Marathon Orogen on Late Paleozoic Tectonics and Sedimentation in Laurentia and Gondwana

Sunday, 9 October 2022
1:30 PM - 5:30 PM
504

SEDIMENT PROVENANCE OF MIDDLE-LATE MISSISSIPPIAN CLASTIC UNITS WITHIN THE BLACK WARRIOR FORELAND BASIN, USA

Paper number: T40-10
Program: Technical Sessions
Time: 3:45 PM – 4:00 PM

Authors

Abstract

We present detrital zircon U-Pb geochronology of the Late Mississippian Hartselle Sandstone and the Middle-Late Mississippian Pride Mountain Formation (Evans and Lewis sandstone units) in the Black Warrior foreland basin to investigate late Paleozoic sedimentary systems and paleogeographic relationships along the southern Laurentian margin. Hartselle Sandstone samples are defined by a major population at ~ 440-430 Ma, with secondary Grenville and Yavapai-Mazatzal populations. A ~ 420-405 Ma population dominates the Evans Sandstone samples, with trace Grenville, Midcontinent, and Yavapai-Mazatzal populations. The notably lower proportion of Grenville grains in the Evans age spectra is unique within eastern U.S. Paleozoic strata. The Lewis Sandstone samples are composed of a major population at ~ 430-425 Ma, as well as secondary Grenville, Midcontinent, and Yavapai-Mazatzal populations. Dissimilarity statistical tests using DZstats show that the Hartselle, Evans, and Lewis samples exhibit proportional differences but similar age spectra. Differences in proportions may be controlled by tectonic development of the Ouachita and southern Appalachian thrust belts, local to regional depositional processes, and or regional climate. We interpret a similar sediment source for all three units based on the presence of ~ 420 Ma grains, which presumably correlates with a Gondwanan provenance to the south. To substantiate this interpretation, as well as other Paleozoic sediment provenance reconstructions, further chemical-age and thermochronology data is needed to supplement detrital zircon geochronology.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-383308

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