193-4 Tracking Early Paleozoic Sediment Organization in the Michigan Basin Using U-Pb Detrital Zircon Geochronology

Session: Advances and Applications in Geochronology for Interpreting Stratigraphic and Basin Records (Posters)

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Abstract:

We present U-Pb detrital zircon geochronology on the Cambrian Mt. Simon and Ordovician St. Peter Sandstones of the Michigan Basin to identify major sediment sources. U-Pb age spectra from LA-ICP-MS analysis of ~300 grains per sample indicate primary sediment contributions from the Superior Craton (3.0–2.5 Ga), Grenville Orogen (1.3–1.0 Ga), and Granite-Rhyolite Province Intrusions (1.5-1.3 Ga). Source signatures vary geographically across the basin, with easterly samples displaying signatures dominated by Granite-Rhyolite and Grenville sources in the Cambrian and Ordovician, respectively, while Superior Craton-dominated samples are restricted to the northwest region of the basin during both time periods. This spatial variability in sources across the basin suggest localized erosion and/or barriers within the basin preventing sediment mixing. 

The U-Pb geochronologic data provide the necessary framework for forthcoming zircon (U-Th)/He thermochronology, which will target grains from the identified source regions to obtain cooling and exhumation ages. The resulting exhumation ages will be used to explore the effects of evolving vegetation on erosion and quantify erosion rates from the respective source regions to the basin through the early Paleozoic. The Michigan Basin, receiving sediment from both tectonically stable and active source regions, offers an ideal setting to investigate how erosional processes respond to evolving biological (e.g., vegetation) and tectonic controls. 

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6949

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