4 D2. Igneous and Metamorphic Processes — From Kimberlites to Meteorites (Posters)

Sunday, 9 March 2025
1:30 PM - 5:00 PM
Lower Level Lobby

UPDATED EMPLACEMENT TIMING OF MAGMATIC UNITS IN THE WICHITA IGNEOUS PROVINCE, SOUTHWESTERN OKLAHOMA

Paper number: 4-12
Program: Technical Sessions
Time: 1:30 PM – 5:00 PM

Authors

Abstract

The Wichita Igneous Province (WIP) of southern Oklahoma, historically interpreted as a part of a failed rift system, provides a well-preserved snapshot of upper crustal magmatic processes during Early Cambrian time. Despite decades of study, interpreting the relative and absolute timing of the emplacement of bimodal intrusive units and felsic extrusives, and the post-emplacement tectonothermal evolution of the crust has proved challenging. Recent high-precision U-Pb dating of several units, including three granites, two gabbros, and rhyolite, have shown that the temporal evolution of the system is tightly clustered; all dated igneous units within the WIP were either crystallized or erupted within a 2.5 Myr span between 533-530 Ma. However, several disparate plutonic units have yet to be constrained with high-precision dating. We present new results from high-precision U-Pb dating of titanite, zircon, and monazite from the Rush Lake and Medicine Park granites, the Mt. Sheridan, Sandy Creek, and Mt. Baker gabbros, and the Davidson metarhyolite. ID-TIMS analyses reported here provide a more complete picture of the magmatic evolution of the system and help provide an updated emplacement model. Ongoing work focuses on determining a complete tectonothermal history of the crust in the WIP. Recent petrographic and SEM analyses have confirmed significant mineralogical alteration, with chlorite and sericite pseudomorphs after biotite indicating potential thermal overprints. To constrain these impacts, we are performing 40Ar/39Ar, U-Th/He, and fission-track thermochronometry to capture mid- to low-temperature events. This integrated approach will provide new constraints on the P-T-t evolution of the WIP, addressing knowledge gaps in the emplacement and post-emplacement history of the province. Results will contribute to a refined understanding of Southern Oklahoma Aulacogen dynamics and its broader role in the tectonic evolution of southern Laurentia.

Geological Society of America Abstracts with Programs. Vol. 57, No. 1

doi: 10.1130/abs/2025SC-408930

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