292-9 Climate-Halokinetic Coupling During the Carnian Pluvial Episode: Paradox Basin, Utah

Abstract:

Climatic perturbations that alter the hydrologic cycle may strongly influence salt deformation, affecting surface uplift and synkinematic sedimentation. The Carnian Pluvial Episode (CPE; 234 – 232 Ma) represents a major humid interval interrupting the otherwise largely arid Triassic and provides an opportunity to examine climate–halokinetic coupling. I am investigating the timing of Upper Triassic fluvial growth strata of the Chinle Formation preserved within actively subsiding salt-withdrawal minibasins between rising salt walls in the Paradox Basin, Utah. I hypothesize that CPE-related moisture contributed to the development of highly weathered paleosols within the lower Chinle Formation, while also accelerating salt withdrawal and minibasin subsidence rates via increased sediment generation. I am testing the hypothesis through the determination of maximum depositional ages of Chinle strata using laser-ablation U–Pb detrital-zircon geochronology. A robust maximum depositional age of 226.6 ± 1.8 Ma (n = 67/122) from strata immediately overlying the weathered interval is consistent with the interval being approximately coeval with the CPE, although additional age constraints are still required for strata within and below the interval. These results provide insights into the effects of climatic perturbations on salt tectonic systems and could improve predictions of geological hazards associated with existing salt structures in environments of rapid climate change.

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