Physical Sciences and Mathematics Commons^™

Environment Of Deposition Of The A-1 Carbonate, Salina Group, Michigan Basin, Barbara June Leonard

Masters Theses

The lower Salina Group of the Michigan Basin is composed of a cyclic succession of carbonate and evaporite units. The lowermost Salina unit is the A-1 unit which consists of a lower A-1 evaporite and an upper A-1 carbonate. The A-1 unit is underlain by Niagara Group carbonates. The transition from Niagaran carbonates to A-1 evaporite to A-1 carbonate has not been thoroughly understood and previous models have not satisfied some of the evidence. This paper sets forth the hypothesis that the A-1 carbonate was deposited in a non-marine lake environment rather than an isolated marine environment. Findings supporting this …

The Geology Of The Southern Bull Mountain Area, Jefferson County, Montana, Michael Edward Streeter

Masters Theses

The Late Cretaceous-Early Tertiary Laramide orogeny was responsible for the northward tilting of the pre-Eocene rocks of the area. The Late Cretaceous deposition of the Elkhorn Mountains Volcanics resulted in the volcanic-Madison Group unconformity. Late Cretaceous faulting took place probably in response to caldera subsidence. Laramide uplift erosion and downstream transport resulted in the deposition of the Conrow Creek conglomerate and debris flows over the Lodgepole Limestone. Block faulting took place in response to regional extension probably during Late Oligocene-Early Miocene time resulting in the formation of the St. Paul's Gulch, Golden Sunlight, and Boulder basin faults. The Oligocene Dunbar …

Sedimentation Rate Of Salt Determined By Micrometeorite Analysis, James Matthew Barnett

Masters Theses

The sedimentation rate of the A-l Evaporite of Michigan was determined by analysis of micrometeorites found as inclusions in the halite deposit. The samples were obtained from the Dow Chemical Company salt well number eight. The residue from the dissolved salt was magnetically separated and later analyzed by Particle Induced X-ray Emission (PIXE), X-ray diffraction , and microprobe techniques. The amount of extraterrestrial material was determined from the quantity of nickel present.

A sedimentation rate of .01 to .4 centimeters per year was calculated for the salt based on a constant influx rate of meteoritic material of 1 x 10 …

The Geology And Geochemistry Of The Summit Creek Molybdenum Prospect, Custer County, Idaho, Thomas Murray Hanna

Masters Theses

The Summit Creek stock, a molybdenum prospect located in the Pioneer Mountains of central Idaho, is a 46.7 m.y. old medium grained, slightly porphyritic quartz monzonite, which has intruded the late Ordovician Phi Kappa formation. Trend surface analysis shows that the stock is the product of one intrusive event. Pervasive mineral alteration usually associated with such porphyry (stockwork) molybdenum deposits is not present in this pluton, and the alteration that is present is confined to local faults and fractures.

Geochemical and petrographic evidence suggest that the pluton is a felsic differentiate from a melt which originated at a depth of …

The Geology Of Burnt Ridge Quadrangle And Vicinity Ravalli County, Montana, Randall Reichert

Masters Theses

Peltitic schist, quartzofeldspathic gneiss, and calc-silicate rocks of the Precambrian Belt Supergroup hav ebeen intruded by granatic plutons of the northeastern Idaho batholith within the vicinity of the southern Bitterroot Range, Montana. These units were mylonitized along the eastern margin of the intrusive complex, with shear surfaces presently dipping approximately 20° to the east. Rhyolitic ash flows and associated mafic to felsic dikes developed on and within the granitic-metamorphic terrance during Tertiary time. Numerous northeast- trending and northwest-trending faults and joints are present throughout the mapped region.

The following events play a major role in the geologic history: 1) amphibolite- …

Lithofacies Analysis Of The Roubidoux Formation, South Central Missouri, Michael William Harbaugh

Masters Theses

"Lithologic and thickness data of the Lower Ordovician rocks of the Roubidoux Formation, south central Missouri, were interpreted from sample logs. Maps included are based on structure, thickness and lateral and vertical lithologic variability. Sand distribution in the Roubidoux is represented by a "sand percentage" map, a "sand isolith" map, and a "tripartite sand distribution" map. The Roubidoux Formation consists of a sequence of dolomite, sandy dolomite, sand and chert. It is believed that the Roubidoux was deposited on a stable marine platform receiving a supply of elastics from the north and northeast. The sands were deposited by longshore or …

Geochemistry And Petrology Of The Cold Springs Breccia Formation, Wichita Mountains, Oklahoma, Dana Marie Vidrine

Masters Theses

"In the Wichita province of southwestern Oklahoma the Cold Springs Breccia Formation, exposed in a 15 km² area in Kiowa County, is characterized by blocks and pillows of microdiorite surrounded by pink granite. Intimately associated with this mixed zone are sill-like bodies of intermediate rocks, granodiorites and tonalites. The intermediate rocks have been interpreted as hybrids produced by assimilation of microdiorite by granitic magma, and the mixed zone has been interpreted as an intrusion breccia formed at the margins of the hybrid sills.

Major, minor and trace element data have been obtained on a suite of granites, intermediates, and …

Mineralogy And Chemistry Of The Tuff On Pritchards Station, East-Central Nevada, Stanley Christopher Hatfield

Masters Theses

"The Tuff of Pritchards Station in east-central Nevada is a little-known ash-flow tuff of limited areal extent. A detailed study of this tuff was conducted to determine if it is a distinctive unit which can be correlated from one locality to another.

Mineralogical and chemical data indicate that the Tuff of Pritchards Station displays significant lateral variability. Lateral variations in mineralogy include changes in total crystal content and the amount and grain size of individual minerals present over the area studied. Chemically, the tuff is a quartz latite to rhyodacite in composition. However, certain elements, most noteably titanium, show considerable …

Lead-Zinc Metallotects Of The Ozark Dome, Linda Leigh Mallery

Masters Theses

"This is a regional study of the relationship between Mississippi Valley-type mineral deposits and structural features of the Ozark dome which resulted in the description and classification of lead-zinc "metallotects". A more accurate delineation of the Ozark dome was accomplished by examining the gradient and structural contour lines of its Precambrian basement. A general background on the geology, structure, and evaluation of the Ozark dome was discussed along with the stratigraphy, structure, and ore deposits of the major lead-zinc districts of the Ozark dome in order to develop the background data for the application of the "metallotect" concept. The major …