Abstract
Detangling the pace and structure of biotic turnover between the late Early and early Late Cretaceous within the Western Interior of North America requires refined stratigraphic controls of fossiliferous sediments; however, to date, many key mid-Cretaceous strata remain understudied and only tenuously or coarsely correlated. Intensified data collection in the uppermost Cedar Mountain Formation (Mussentuchit Member) suggests preservation of an understudied volcanilithic archive that can provide key insight into this enigmatic period in North America's geological history. Here we utilize detrital zircon geochronology (coupling LA-ICP-MS and CA-TIMS) to contextualize the sedimentary history of the Mussentuchit Member within the region of Mussentuchit Wash, Central Utah and compare these data with previous approaches. This study finds that emplacement of contemporaneous volcanilithics occurred in two distinct phases. The first phase occurred no older than 96 Ma, and a subsequent younger phase occurred no older than 94 Ma. Secondly, this study finds preliminary evidence that both eruptions occurred within a westerly lying arc; however, it is evident that these represent different volcanic inliers and terranes. Finally, this study also finds that the Mussentuchit Member can be reliably subdivided into two informal lower and upper sub-members, with the potential to preserve two distinct, previously unified fossil assemblages. Our data provides both a refined localized framework for newly uncovered fossil assemblages within this particular Mussentuchit Wash depo-centre and serves to strengthen correlations between mid-Cretaceous strata across the Western Interior.
Original language | English (US) |
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Article number | 104384 |
Journal | Cretaceous Research |
Volume | 110 |
DOIs | |
State | Published - Jun 2020 |
Externally published | Yes |
Bibliographical note
Funding Information:We thank staff, students, and volunteers of the 2015–2019 expeditions for repeated explorations of the Mussentuchit Member; M. Leschin, S. Foss, G. McDonald, R. Hunt-Foster, J. Kirkland, M. Hayden, J. Krishna, R. Irmis, staff of the Price Field Office, the Bureau of Land Management Utah State Office, Natural History Museum of Utah, and Utah Geological Survey for permitting and expedition support. Special thanks go to R. Rossouw, and L. Bracciali of the Central Analytical Facility at Stellenbosch University and Huang, H. at the Advanced Analytical Centre at James Cook University during preparation and data reduction of LA-ICP-MS data, along with J. Crowley at the Department of Geological Sciences at Boise State University for CA-TIMS analysis and data reduction. Financial support was provided by Stellenbosch University's Department of Earth Sciences (RSA), SU-DRD Fund (RSA), F. Kruger (MyBrew) (RSA), North Carolina Museum of Natural Sciences (USA), the Canyonlands Natural History Association (USA). Lastly we would like to especially thank the editor and both anonymous reviewers, whose comments and alterations greatly strengthened this manuscript to its current state.
Funding Information:
We thank staff, students, and volunteers of the 2015–2019 expeditions for repeated explorations of the Mussentuchit Member; M. Leschin, S. Foss, G. McDonald, R. Hunt-Foster, J. Kirkland, M. Hayden, J. Krishna, R. Irmis, staff of the Price Field Office, the Bureau of Land Management Utah State Office, Natural History Museum of Utah, and Utah Geological Survey for permitting and expedition support. Special thanks go to R. Rossouw, and L. Bracciali of the Central Analytical Facility at Stellenbosch University and Huang, H., at the Advanced Analytical Centre at James Cook University during preparation and data reduction of LA-ICP-MS data, along with J. Crowley at the Department of Geological Sciences at Boise State University for CA-TIMS analysis and data reduction. Financial support was provided by Stellenbosch University's Department of Earth Sciences (RSA), SU-DRD Fund (RSA), F. Kruger (MyBrew) (RSA), North Carolina Museum of Natural Sciences (USA) , the Canyonlands Natural History Association (USA). Lastly we would like to especially thank the editor and both anonymous reviewers, whose comments and alterations greatly strengthened this manuscript to its current state.
Publisher Copyright:
© 2020 Elsevier Ltd
Keywords
- Cedar Mountain Formation
- Chronostratigraphy
- Mussentuchit Member
- Mussentuchit Wash
- U–Pb geochronology