194-1 Thermal evolution of the Newark Basin: Insights from Zircon U-Th/He Thermochronology

Session: Broad Applications of Thermochronology to Understanding Geologic Rates and Processes Through the Sedimentary Record (Posters)

Poster Booth No.: 180

Presenting Author:

Zachary Foster-Baril

Authors:

Foster-Baril, Zachary S.¹, Stockli, Daniel F.², Flansburg, Megan Elysia³, Kinney, Sean Thomas⁴, Olsen, Paul E.⁵

Abstract:

Despite extensive study and its value as an analog for modern and fossilized continental rifted margins, key aspects of the tectono-thermal evolution of the Eastern North American Margin (ENAM) remain enigmatic. Triassic-Jurassic syn-rift strata are preserved in a series of primarily east-dipping half-grabens, recording the lithospheric response to rifting that culminated in continental breakup and Atlantic opening. Recent U-Pb provenance data from the Newark Basin record a shift to sediment derived from the footwall during the Norian syn-rift phase, consistent with rift flank uplift during lithospheric necking. However, geochronologic constraints of the tectono-thermal evolution of the Newark Basin during progressive rifting remain limited. Published vitrinite reflectance data are indicative of significant heating and/or burial of the Newark Basin early syn-rift strata and up to 6 km post-rift erosion. This study employs new zircon (U-Th)/He thermochronology to provide new temporal constraints on the rift-to-drift transition of the ENAM. Here we present new zircon (U-Th)/He results and thermochronologic modeling of bedrock samples from both the footwall and hanging wall of the Newark Basin, as well as detrital samples from the Carnian syn-rift Stockton Formation. Mean apparent zircon (U-Th)/He ages from a transect spanning the Newark Basin footwall to hanging wall range between 213 and 169 Ma. In general, mean zircon (U-Th)/He ages decrease toward the basin-bounding fault. The lack of pre- and syn-depositional zircon (U-Th)/He ages preserved in the basin suggests significant post-depositional burial and hydrothermal circulation reset the zircon (U-Th)/He system. Preliminary HeFTy inverse time-temperature models suggest that footwall rocks cooled through the zircon (U-Th)/He partial retention zone between ca. 220 and 180 Ma. Rocks on the hanging wall side, including within the Newark Basin, cooled through the zircon (U-Th)/He partial retention zone between ca. 190 and 150 Ma. The syn-rift cooling of the Newark Basin footwall is consistent with stratigraphic and provenance shifts indicative of rift flank uplift in the Norian. The post-rift cooling of the footwall near the basin-bounding fault is consistent with thermal resetting due to hydrothermal circulation. The results from the hanging wall align with previous vitrinite reflectance studies, indicating significant erosion during the Early Jurassic. Further work will address potential complexities such as the thermal effects associated with the Palisades Sill.

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

doi: 10.1130/abs/2025AM-10322

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