Date of Award
5-2019
Degree Type
Thesis
Degree Name
Master of Science - Geology
Department
Geology
First Advisor
Dr. LaRell Nielson
Second Advisor
Dr. Kevin Stafford
Third Advisor
Dr. Julie Bloxson
Fourth Advisor
Dr. Joseph Musser
Abstract
The Fort Terrett Formation was deposited on the western edge of the Comanche Shelf in central Texas. The predominate lithology of the Fort Terrett Formation is limestone which caps the hills that surround Junction, Texas. Deposition of the Fort Terrett Formation occurred within shallow, quiet waters during the Lower Cretaceous. Rose (1974) developed a general stratigraphic correlation and lithostratigraphic framework for the Cretaceous Shelf and established a regional correlation. Four stratigraphic divisions have been recognized in the Fort Terrett Formation. These are: a basal nodular unit, a burrowed unit, a dolomitic unit, and the Kirschberg evaporites. Wilkerson (2018) provided the addition of the Walnut Formation as part of the local stratigraphy. However, both the Walnut Formation and Kirschberg evaporites have been omitted from the local stratigraphy. In the Junction area, measured sections by Rose (1972) of the Fort Terrett Formation contain the lower two units which are the burrowed unit, distinguishable by bioturbation, and the basal nodular unit. Nine sections of the Fort Terrett Formation were measured along road cuts on I-10 near Junction, Texas and hand samples collected. This data was used to divide the Fort Terrett Formation into three lithostratigraphic units. The lower unit contained thick-bedded limestone representing an open marine carbonate platform. The middle unit contains extensive chert nodules and fossils that indicate intertidal to subtidal facies. The upper unit contains thick bedded limestone with dolomite indicating shallow intertidal facies. This study has divided the Fort Terrett Formation into 6 facies in the Junction area to determine depositional environment. Diagenesis of the Fort Terrett Formation is complex ranging from shallow marine diagenesis, burial, hydrothermal, and telogenesis. Dolomization of the Fort Terrett is also the focal point of several previous study. This study is to provide a new perspective on late stage dolomization by burial and hydrothermal activity.
Repository Citation
Urwin, Richard Alden Jr., "FACIES AND DIAGENESIS ANALYSES OF THE FORT TERRETT FORMATION OF THE LOWER CRETACEOUS EDWARDS GROUP, NEAR JUNCTION, TEXAS" (2019). Electronic Theses and Dissertations. 276.
https://scholarworks.sfasu.edu/etds/276
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