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Stratigraphic Correlation of the Upper Cretaceous
Stratigraphic Correlation of the Upper Cretaceous
Figure 1: Upper Cretaceous strata within several Wyoming basins. Formations of note is the Mesaverde Formation/Group, the Meeteetse Formation, and the Lance Formation. Modified from Lynds and Slattery, 2017.
I am interested in improving the chronostratigraphic correlation of the Upper Cretaceous across Wyoming and surrounding regions. Though many of these nonmarine deposits are highly fossiliferous, the depositional age remains poorly constrained preventing high-resolution correlation.
Campanian: The primary strata composing nonmarine deposits from the Campanian is the Mesaverde Formation/Group. In southern Wyoming, the Mesaverde Group contains several nonmarine formations spanning the lower, middle, and upper Campanian; including the Rock Springs Fm., Ericson Sandstone, Allen Ridge Fm., and Almond Fm. In northern and central Wyoming the Mesaverde Formation is composed of several members from the middle and upper Campanian; including the Fales Sandstone, middle member, and Teapot Sandstone.
Maastrichtian: The lower Maastrichtian Meeteetse Formation and upper Maastrichtian Lance Formation are the two most prominent nonmarine Maastrichtian deposits. The Meeteetse Fm. has received minimal fieldwork with few fossil localities having been reported, though has great potential for new discoveries. The Lance Formation outcrops across the state though the correlation between the outcrops and age has received minimal investigation.
Stratigraphic Paleobiology and Paleobiogeography
Stratigraphic Paleobiology and Paleobiogeography
Another interest of mine is examining changes in paleoecological diversity stratigraphically and geographically. Wyoming is an area that specifically requires additional research due to it helping to fill a gap between northern and southern ecosystems in Laramidia. Northern paleoecosystems during the Campanian in Alberta and Montana contain temperate faunas and floras compared to subtropical faunas and floras in southern paleoecosystems in Utah and New Mexico (Burgener et al, 2021).
By examining the stratigraphic distribution of fossils we can start to identify changes in depositional environment. These changes can be related to the transgression and regression of the Western Interior Seaway and relative distance from paleoshores. This type of examination will provide a greater understanding of variations in paleoecosystems through deep-time.
Figure 2: Stratigraphic distribution of fossil occurrences in the nonmarine member of the Mesaverde Formation in central Wyoming.
Figure 3: Paleogeographic maps of Wyoming containing fossil localities from the University of Wyoming Vertebrate Paleontology Collections and the Tate Geological Museum. A) Paleogeographic map from the middle Campanian (Baculites scotti zone). B) Paleogeographic map of the K/Pg Boundary. Map data from Keith Minor.
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