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Graduate Student Theses, Dissertations, & Professional Papers

Theses/Dissertations

Geology

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Full-Text Articles in Physical Sciences and Mathematics

Petrogenesis And Tectonic Implications Of Cordierite-Orthoamphibole Gneisses (Cog) In The Nw Wyoming Province, Brianna K. Crenshaw Ms Jan 2021

Petrogenesis And Tectonic Implications Of Cordierite-Orthoamphibole Gneisses (Cog) In The Nw Wyoming Province, Brianna K. Crenshaw Ms

Graduate Student Theses, Dissertations, & Professional Papers

Studying cordierite orthoamphibole gneisses (COG) from five different mountain ranges across the Montana Metasedimentary Terrane (MMT) of the Wyoming Province offers a unique opportunity to elucidate the enigmatic origins and petrogenesis of the lithology in addition to gaining a further understanding of Precambrian crustal assembly processes. Geochemical analyses suggest that COG originates from a basalt that underwent metasomatic alteration, likely via seawater, prior to metamorphism. Moreover, COG is considered to represent oceanic crust that was part of the epicontinental sea adjacent to the Wyoming Province before collision with the Medicine Hat Block. Field observations of associated lithologies such as marbles, …


An Inter-Watershed Comparison Study Of Bedrock Controls On Shallow Subsurface Flow And Streamflow Response, Robert Livesay Jan 2018

An Inter-Watershed Comparison Study Of Bedrock Controls On Shallow Subsurface Flow And Streamflow Response, Robert Livesay

Graduate Student Theses, Dissertations, & Professional Papers

Bedrock controls on watershed response have been actively studied in recent years, however, most conclusions are based on surface water analysis leaving unresolved questions about the nature of bedrock flow paths and ultimately their control on watershed response. In this study, we investigated bedrock controls on watershed response by simultaneously monitoring the hydrology of two adjacent watersheds underlain by dissimilar geologic formations (monzonite vs. meta-sandstone) and by characterizing subsurface conditions through bedrock drilling and fracture mapping. We hypothesized, when soils saturate, the underlying bedrock geology may influence the partitioning of shallow subsurface flow (SSF) between soil and bedrock flow paths, …


The Neocene Lake Beds Of Western Montana And Descriptions Of Some New Vertebrates From The Loup Fork, Earl Douglass Jan 1899

The Neocene Lake Beds Of Western Montana And Descriptions Of Some New Vertebrates From The Loup Fork, Earl Douglass

Graduate Student Theses, Dissertations, & Professional Papers

Since coming to Montana in the spring of 1894 I have spent rnuoh of ay time in studying the lake bed deposits in the western part of the state, and in collecting and studying the vertebrate fossils found in them. These deposits occur in nearly every large valley in the westem part of the state. I have myself observed them in the valleys of the upper Missouri (above the re-rrion of Helena), Gallatin, Madison, Jefferson, Beaverhead, Ruby, Big Hole, Hell Gate, and Bitter Boot rivers, and their tributaries.