Document Type
Grant
Publication Date
9-1-2016
Department
Geoscience
Abstract
The Hell Creek Formation is a group of laterally extensive sedimentary beds exposed throughout North Dakota and Montana. It is one of the best exposures of Late Cretaceous sediments in the world and is known for its iconic dinosaur fossil assemblages. To obtain more detailed information about the timing and impact of the Cretaceous - Paleogene (K-Pg) mass extinction it is important to precisely determine the stratigraphic location of the K-Pg boundary, which is found near the top of the Hell Creek Formation. Palynology can be used to determine this boundary by observing the relative abundances of fossilized pollen. Previous palynological analysis has described relative abundances of pollen samples throughout the region of exposed Hell Creek strata across the contact between the Hell Creek and overlying Fort Union Formations. A significant decrease in pollen abundance corresponds to the mass extinction event that marks the end of the Cretaceous period. Locally, the K-Pg boundary must first be identified using palynological analysis. The stratigraphy of the boundary can then be determined more precisely in this region. Sediment samples from the Hell Creek Formation near Marmarth, North Dakota were collected from the top of a butte estimated to be close to the stratigraphic K-Pg boundary. These samples were prepared for analysis at the University of Minnesota's LacCore pollen processing lab. Microscopic analysis to determine relative abundances of pollen species was performed at Winona State University. Knowing the stratigraphic location of the boundary near Marmarth will allow for more extensive studies of the K-Pg extinction and help to temporally locate excavations in the area. Better stratigraphic understanding of the boundary throughout the Hell Creek Formation will increase our understanding of the timing of the extinction and the environmental conditions before, during, and after the event.
Content Notes
Poster
First Advisor
W.L. Beatty
