A case study of maximum depositional ages from terrestrial sandstones near the Cretaceous—Paleogene transition, western Williston Basin, USA

Andrew Tholt; Jack N. Carter; Neil Patrick Griffis; Roland Mundil; Gregory Wilson-Mantilla; Laura Pianowski; Anthony Fuentes; Paul R. Renne

USGS · 70279680

A case study of maximum depositional ages from terrestrial sandstones near the Cretaceous—Paleogene transition, western Williston Basin, USA

Andrew Tholt·Jack N. Carter·Neil Patrick Griffis·Roland Mundil·Gregory Wilson-Mantilla·Laura Pianowski·Anthony Fuentes·Paul R. Renne

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Abstract

We present a new Bayesian method for deriving maximum depositional ages from detrital K-feldspar using total-fusion 40 Ar/ 39 Ar data. Individual analyses weighted by K/Ca ratio, age uncertainty, and percent radiogenic argon prioritize a result to come from accurately measured volcanic sources. Results from this method applied to sandstones from the Hell Creek region of northeastern Montana show that detrital K-feldspar maximum depositional ages align closely with detrital U-Pb zircon ages as well as tephra based chronostratigraphic constraints from both 40 Ar/ 39 Ar and U-Pb data. An age model informed by maximum depositional ages and available tephra data provides an estimate of 1.74 ± 1.04 Ma for the duration of deposition for the Hell Creek Formation. Combined age model and maximum depositional age data suggest ≤ 1.84 Ma of missing time is represented by the Hell Creek and Fox Hills formational disconformity, coinciding with the final regression of the Western Interior seaway.

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Andrew Tholt, Jack N. Carter, Neil Patrick Griffis, Roland Mundil, Gregory Wilson-Mantilla, Laura Pianowski, Anthony Fuentes, Paul R. Renne. 2026-08-24. A case study of maximum depositional ages from terrestrial sandstones near the Cretaceous—Paleogene transition, western Williston Basin, USA. https://pubs.usgs.gov/publication/70279680

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Article subject Geochronology, Thermochronology and Time Scale Research subject Hell Creek region place Montana place United STates place

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