Earth Sciences Commons^™

Geology Of The Cuesta Ridge Ophiolite Remnant Near San Luis Obispo, California: Evidence For The Tectonic Setting And Origin Of The Coast Range Ophiolite, Cameron A. Snow

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Cuesta Ridge ophiolite is one of the best-preserved remnants of mid-Jurassic ophiolite in California. Geologic mapping and petrologic studies show that it comprises (1) harzburgite mantle tectonite, (2) dunite-rich mantle transition zone (MTZ), (3) wehrlite and pyroxenite, (4) isotropic gabbro, (5) sheeted dike/sill complex, (6) volcanic rocks (7) late-stage dikes and flows, and (8) tuffaceous radiolarian chert.

The sheeted dike/sill complex is dominated by quartz diorite, with significant modal quartz and hornblende. The volcanic section is dominated by arc tholeiite and boninitic lavas. Boninites, with high MgO, Cr, and Ni comprise 40% of the volcanic rocks. Latestage dikes and …

Laramide Deformation In Precambrian Granitic Rocks, Northeastern Wind River Range, Wyoming, Mark A. Dubois

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fractures and faults in the Jakey's Fork area, northeastern Wind River Range, Wyoming, caused by brittle Laramide deformation in the Precambrian granitic basement have been studied in detail at airphoto, outcrop, and thin-section scales. The study area is bounded on the south by the approximately east-west and vertical Jakey's Fork Fault and on the east by the approximately northwest-southeast and vertical Ross Lakes Fault. Both were active during Laramide deformation. Four distinct structural domains, defined by fracture pat terns and proximity to the two major faults nave emerged in this study. The areas are: 1) Along Ross Lakes Fault granite …

Mineralization In The Bear River Range, Utah-Idaho, John C. Chappelle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this thesis is t o describe the occurrences, interrelationships, and possible origin of the metallic mineral deposits of the Bear River Range. In this study, 21 mineral deposits containing minerals of lead, iron, copper, manganese, and zinc with quartz and carbonate gangue minerals, are described and classified as low temperature epigenetic hydrothermal deposits. The deposits predominantly occur in Cambrian limestone and dolomite formations located below formations with a high shale content. The deposition occurred as fracture filling and replacement along fractures associated with Teritary Basin and Range normal faults and joints which generally trend northerly in the …

Environmental Analysis Of The Swan Peak Formation In The Bear River Range, North-Central Utah And Southeastern Idaho, Philip L. Vandorston

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Swan Peak Formation in the Bear River Range of northern Utah and southeastern Idaho varies in thickness from 0 feet to over 400 feet. It consists of three units: (1) a lower unit of interbedded quartzites, shales, and limestones; (2) A middle unit of interbedded quartzites and shales; (3) An upper unit of nearly homogeneous quartzites. The different sedimentary structures, ichnofossils, body fossils, and mineral compositions of each unit represent different environments of deposition. The lower unit probably was deposited in a shallow-shelf environment, and its sediments grade upward into probably shoreface-, tidal-flat-, and lagoonal deposits of the middle …

The Devonian Of The Bear River Range, Utah, I. Lavell Cooley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The geological column in northern Utah has had very little detailed study. Those who have made reports on this section have done so only in a very general way, making no detailed sections of any part of the column, excepting that of the Cambrian made by Walcott.¹ Other work has been done by Mansfield² in southeastern Idaho and a general section of the Devonian made in Green Canyon, Bear River Range, Utah by Kindle.³

Due to the lack of any detailed work of this nature being done in the Bear River Range, suggested the matter of making …