Department
Geosciences
Degree Name
Master of Science (MS)
Abstract
The Crow Creek Member of the Pierre Shale (Upper Cretaceous) is a westward projecting tongue of siltstone overlain by marl, which crops out along the Missouri River and its tributaries in South Dakota. / Seventy-nine samples from 15 measured sections and one subsurface core were analyzed for x-ray bulk rock mineralogy, insoluble residues, and limited clay mineralogy, heavy minerals, and paleontologic elements. X-ray diffraction values reveal geographic and stratigraphic trends in the four major mineralogic components (quartz, calcite, dolomite, and clay minerals). These, coupled with trends in the insoluable residue values, suggest that the Crow Creek sediments were deposited in a transgressive, near shore, shallow shelf environment. Elements of the fauna support this and also suggest that the unit was deposited in near normal to normal marine, mid to warm temperate waters. Periodic (probably seasonal) high energy conditions disrupted the bottom community and led to physical destruction of most macrofossil shells. The shell fragments were then subjected to geochemical destruction and/or alteration. Dolomite was formed by both supratidal flat and reflux mechanisms. Regional epeirogenic uplift in east-central and southeastern South Dakota supplied the detrital fraction and, coupled with the transgression, controlled the geographic and lithologic configurations of the member.
Keywords
Geology
Advisor
Dr. Michael E. Nelson
Date of Award
1979
Document Type
Thesis - campus only access
Recommended Citation
Bretz, Richard F., "Stratigraphy, Mineralogy, Paleontology and Paleoecology of the Crow Creek Member, Pierre Shale (Late Cretaceous) South Central South Dakota" (1979). Master's Theses. 1746.
DOI: 10.58809/UMLQ7237
Available at:
https://scholars.fhsu.edu/theses/1746
Rights
© The Author(s)
Comments
For questions contact ScholarsRepository@fhsu.edu