Also known as Egg Shell Quarry; OMNH V820

Where: Emery County, Utah (39.1° N, 111.0° W: paleocoordinates 40.3° N, 73.1° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Mussentuchit Member (Cedar Mountain Formation), Early/Lower Cenomanian (99.6 - 93.5 Ma)

• Tucker et al. 2020: 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.

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•A radiometric age of 98.37 ± 0.07 Ma was obtained by the OMNH from volcanic ash within the Mussentuchit Member (Cifelli and others, 1997, 1999). Additional ages by Garrison and others (2007) ranging from 96.7 ± 0.5 to 98.2 ±0.6 Ma indicate that the Mussentuchit Member was deposited over an interval of 1.5 Ma during the early Cenomanian and supports a correlation with the siliceous marine Mowry Shale to the north, which is well-constrained from 40Ar/39Ar sanidine ages obtained from bentonite beds that bracket the Mowry in Wyoming; the basal Arrow Creek Bentonite is 98.5 ± 0.5 Ma and the capping Clay Spur Bentonite is 97.2 ± 0.7 Ma (Obradovich, 1993; Ogg and Hinnov, 2012; Sprinkel and others, 2012) near the base of the Upper Cretaceous.

• bed-level stratigraphic resolution

Environment/lithology: "floodplain"; siltstone and mudstone

Size class: mesofossils

Collected by Robison in 1990-1991; reposited in the CM

Collection methods: bulk, surface (in situ), sieve,

Primary reference: M. E. Nelson and J. H. Madsen. 1985. Early Cretaceous mammals from central Utah. Geological Society of America, Rocky Mountain Section, Abstracts with Programs 17(4):258 [M. Carrano/M. Carrano]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 22679: authorized by Anna Behrensmeyer, entered by Anna Behrensmeyer on 23.04.2001, edited by Matthew Carrano and Philip Mannion

Creative Commons license: CC BY (attribution)