Date of Award
5-1-2026
Document Type
Thesis
Degree Name
M.S. in Engineering Science
First Advisor
Jennifer Gifford
Second Advisor
Brian Platt
Third Advisor
Lance Yarbrough
School
University of Mississippi
Relational Format
dissertation/thesis
Abstract
The Bighorn Mountains (BHMs) of Wyoming show evidence of a long geologic history, beginning in the Archean. The formation of the mountains themselves is due to the Late Cretaceous to Eocene Laramide Orogeny. The state of Wyoming’s bedrock geologic map is at the scale of 1:500,000 and more detailed maps are needed to fully explain the BHM’s history. Mapping projects and structural interpretations such as the Mexican Hill Quadrangle (MHQ) at the 1:24,000 scale, are an example of current research being conducted. Traditional field mapping methods combined with Field Move Clino were used to create a detailed geologic map of the quadrangle along with two interpretive cross sections of the field mapping area. The MHQ contains one basement unit (tonalite, quartz monzodiorite, granodiorite, monzogranite), two diabase dikes, and six sedimentary units (Flathead Sandstone (Ss), Gallatin-Gros Ventre (GGV) formations (fms), Bighorn Dolomite, Madison Limestone (Ls), and Amsden Formation (Fm)). The units in the MHQ demonstrate Laramide deformation through three major structures: monoclinal folding, a reverse/thrust fault, and a shallowly-dipping anticline. The monoclines of the MHQ formed from a blind fault buried within ductile units rather than the major thrust/reverse fault. General trends in the dip of sedimentary units indicate that there was increased uplift in the southern half of the map. The reverse/thrust fault terminated in the northeast corner of the MHQ and influenced flexural slip folding of the GGV fms and Bighorn Dolomite which resulted in the anticline. Continued studying of the structural deformation of the BHMs will provide a clearer history of the range.
Recommended Citation
Johns, Jessica, "Structural Interpretation and Geologic Map of The Mexican Hill Quadranlge, Northwestern Bighorn Mountains, Wyoming, USA" (2026). Electronic Theses and Dissertations. 8836.
https://egrove.olemiss.edu/etd/8836