19 Depositional systems and resource distribution in eastern and southern North America: from orogens to coastal plains

We welcome studies related to the sourcing, dispersal, and deposition of clastic sediments from the hinterlands to the coast, including the provenance, paleogeography, sedimentology, and economic significance of these deposits.

Tuesday, 10 March 2026
8:30 AM - 11:30 AM
RCC, 105

Provenance, Timing, and Paleodrainage Evolution of the Northern Mississippi Embayment during the Eocene: Insights from Detrital Zircon U–Pb Geochronology of the Claiborne Group, Western Tennessee

Paper number: 19-5
Program: Technical Sessions
Time: 9:35 AM – 9:50 AM

Authors

Abstract

Efforts to define the stratigraphy within the northern Mississippi embayment have traditionally focused on lithostratigraphic and hydrostratigraphic relationships, relying on the petrology, sedimentology, and geochemistry from outcrops in combination with geophysical well logs. In western Tennessee, sparce outcrop data hinders correlation of subsurface stratigraphic units which is additionally complicated by erosional unconformities, repetition of lithologically similar units, local tectonic deformation, and heterogeneity of fluvial–deltaic strata. This study presents detrital zircon U–Pb geochronology, analyzed utilizing LA-ICP-MS, from subsurface Eocene Claiborne Group samples to determine sediment provenance, maximum depositional ages (MDAs), and reconstruct paleogeographic drainage networks. Core samples were extracted via rotary sonic drilling from boreholes along a northeast–southwest transect in western Tennessee. Detrital zircon age spectra are dominated by Appalachian (490–270 Ma) and Grenville (1250–900 Ma) populations, with variable amounts of western Cordilleran (270–0 Ma), Granite–Rhyolite (1550–1300 Ma), Yavapai–Mazatzal (1800–1600 Ma), and Wyoming (>2400 Ma) populations. Provenance patterns vary spatially across the transect, with boreholes to the northeast showing decreasing proportions of western Cordilleran and Appalachian zircons alongside increasing Grenville contributions. Maximum depositional ages show considerable variance and are strongly dependent on the statistical method, exhibiting estimates both younger and older than ages inferred from calcareous nannoplankton and foraminiferal biostratigraphy of correlated units in Mississippi and Alabama. Potential causes of these discrepancies may be scarcity or absence of syndepositional zircon populations (due to limited zircon-producing source regions), limited sample size, analytical variability related to inheritance, Pb loss, or LA-ICP-MS uncertainty. Nonetheless, integration of regional biostratigraphy and detrital zircon U–Pb geochronology indicate the Middle Eocene Climatic Optimum (-40 Ma) likely occurred during deposition of the middle to upper Claiborne Group. This expanded dataset suggests that drainage divides during Eocene may have extended farther west and north than previously inferred. Additionally, the increased proportions of Appalachian basin derived zircons on the eastern side of the basin potentially reflects an Eocene paleodrainage configuration analogous to the pre–Missouri River capture of the Quaternary Mississippi River system.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411732

© Copyright 2026 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.