Preprints
https://doi.org/10.5194/egusphere-2024-2899
https://doi.org/10.5194/egusphere-2024-2899
25 Sep 2024
 | 25 Sep 2024

Emplacement Age of the Sevier Gravity Slide, Utah, USA

Tiffany Rivera, McKenna Holliday, Brian Jicha, David H. Malone, Michael J. Braunagel, V. Alex Bonilla Franco, Robert F. Biek, W. Ashley Griffith, and David B. Hacker

Abstract. The Marysvale volcanic field in southwestern Utah hosts three large volume gravity slides: the Sevier (SGS), the Markagunt (MGS), and the Black Mountains (BGS). The gravity slides are composed of lahar deposits, lava flows, and ash-flow tuffs erupted from former stratovolcanoes and other vents during the Oligocene and Miocene. The ash-flow tuffs are prime targets for dating to constrain the age of the gravity slides because some ash-flow tuffs are deformed within the slides, whereas others are undeformed and cap the slides. Furthermore, the gravity slides produced pseudotachylyte during slide motion, a direct indicator for the timing of each slide. This work provides new 40Ar/39Ar dates for several ash-flow tuffs and pseudotachylyte for the SGS, along with U/Pb zircon dates for one deformed tuff and overlying alluvium at the slide plane. Results show that the slide was emplaced at 25.25 ± 0.05 Ma and was immediately followed by the eruption of the Antimony Tuff at 25.19 ± 0.02 Ma. The model presented here suggests that the intrusion of magma related to the Antimony Tuff acted as a triggering mechanism for the slide, and that slide movement itself led to decompression melting and eruption of the Antimony Tuff. This sequence of events occurred on a geologically rapid timescale and may have been virtually instantaneous.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
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Journal article(s) based on this preprint

24 Feb 2025
Emplacement age of the Sevier gravity slide, Utah, USA
Tiffany Rivera, McKenna Holliday, Brian Jicha, David H. Malone, Michael J. Braunagel, V. Alex Bonilla Franco, Robert F. Biek, W. Ashley Griffith, and David B. Hacker
Geochronology, 7, 35–44, https://doi.org/10.5194/gchron-7-35-2025,https://doi.org/10.5194/gchron-7-35-2025, 2025
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

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The timing of an ancient gravity slide that originated in the Marysvale volcanic field (Utah) is...
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