6 A Matter of Time II: Using High-Resolution Stratigraphic and Sedimentologic Techniques to Investigate the Mid-Continent Geologic Record

Monday, 19 April 2021
8:00 AM - 12:00 PM
UALR Earth Science Room

LATE MISSISSIPPIAN TO EARLY PENNSYLVANIAN TRANSITION FROM EXTRAREGIONAL TO LOCAL SEDIMENT SOURCES TIED TO ANCESTRAL ROCKY MOUNTAINS DEFORMATION

Paper number: 6-5
Program: Theme Sessions
Time: 9:05 AM – 9:25 AM

Authors

Abstract

This study explores the influence of the Alleghanian-Oauchita-Marathon orogeny and the Ancestral Rocky Mountains (ARM) uplifts on sediment dispersal in the Carboniferous through detrital zircon provenance analysis. We focus on Upper Mississippian to Middle Pennsylvanian siliciclastic intervals in two areas: (1) the Hugoton Embayment in southwestern Kansas, where six core samples of Chesterian and Morrowan sandstones were collected from two boreholes, Cutter KGS #1 and Hanke A4, located in the axis of a stacked incised valley fill complex and (2) the Arkoma shelf in northwestern Arkansas, where nine samples were collected from sand-rich Chesterian through Desmoinesian outcrops that preserve the transition from a carbonate shelf in the Osagean to mixed carbonate-siliclastic system from the Chesterian through Morrowan, to a clastic-dominated foreland basin in the Pennsylvanian. We report 1544 new concordant ages from these samples, 582 ages from Kansas core and 962 ages from Arkansas outcrops. U-Pb age distributions from these sandstones are characterized by major Grenville (900–1,300 Ma) and Taconic‐Acadian (350–500 Ma) age clusters and minor components of older age groups, suggesting a persistent source in the Appalachians tied to the Alleghanian orogeny. However, by the Early Pennsylvanian, the Hugoton Embayment samples see the Appalachian source partially replaced by Yavapai-Mazatzal (1600–1800 Ma) and Granite-Rhyolite (1300–1550 Ma) grains, major components of the local basement, that may be hinting at contributions from nearby ARM uplifts. In contrast, detrital zircon age spectra of samples from the Arkoma shelf suggest contributions from midcontinent basement sources were limited from Late Mississippian through the Middle Pennsylvanian. Comparison of our data with published data suggest that a similar shift in provenance, from extraregional to local sediment sources, is observed across western Laurentia where ARM deformation was most active. Together, the new and published data support development of a major transcontinental sediment dispersal system in the Late Mississippian that was likely controlled by Alleghanian orogenesis on the eastern Laurentian margin; however, by the Early Pennsylvanian this system was disrupted by development of the ARM uplifts.

Geological Society of America Abstracts with Programs. Vol. 53, No. 3

doi: 10.1130/abs/2021NC-362935

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