Earth Sciences Commons^™

Investigation Of The Sheep Creek Carbonatites, Ravalli County, Montana, Sarah Risedorf

Graduate Theses & Non-Theses

Carbonatite-related REE-Nb mineralization in southern Ravalli County, Montana was first discovered in the late 1950s and early 1960s. Over 30 discontinuous carbonatite bodies occur in a ~ 10 km² area centered on Sheep Creek, a tributary to the headwaters of the West Fork of the Bitterroot River (WFBR). The deposits are contained in a belt that extends to the southeast into the Mineral Hill district of Lemhi County, Idaho. Country rocks include a deformed and metamorphosed bimodal igneous suite of diabase and A-type granite, both dated to 1.37 Ga by previous workers. These rocks are locally metamorphosed to amphibolite …

Mineralogy And Fluid Inclusion Study Of The Marget Ann Mine Of The Butte Mining District, Silver Bow County, Montana, Tiffany Ostenburg

Graduate Theses & Non-Theses

Butte, Montana, is a famous example of a zoned, polymetallic, porphyry-lode deposit. Whereas over a century of previous work has focused on the porphyry-style mineralization and centrally located, copper-rich lode deposits, relatively little has been written on the outer, silver-rich veins. The Marget Ann mine, in the northern portion of the district, was chosen for this study because of ease of access to the mine dumps as well as archived samples of high-grade vein mineralization. In addition, the Marget Ann mine is somewhat unique in Butte because gold has been found there and previously recorded in the veins. The main …

Geology Of The Middle Member Of The Bakken Formation In Divide County, North Dakota, Mandy Brewer

Graduate Theses & Non-Theses

The Upper Devonian-Lower Mississippian Bakken Formation of Williston Basin is a large unconventional oil and gas play consisting of a lower shale member, a middle member, and an upper shale member. The middle member is a production target because it contains porosity and petroleum expelled from the shale members around it. Variable production and sweet spots of the Bakken in the study area of Divide County, ND and 15 miles around Divide County in the USA prompted a closer look at middle member Bakken sediments. For this study, 606 wells were correlated and thin sections from two wells located 10.17 …

Sequence Stratigraphic Correlation Of The Bow Island Member Of The Thermopolis Formation Using Surface Outcrop And Subsurface Data, Liberty And Hill Counties, Montana, Michael Vineyard

Graduate Theses & Non-Theses

The Bow Island Member of the Thermopolis Formation in Montana is a low-pressure gas producer, which formed due to the first (Kiowa-Skull Creek) transgressive–regressive cycles of the Cretaceous Western Interior Seaway.

The Bow Island Member and its correlative units (Viking and Muddy Formations) have been extensively exploited for oil and gas throughout Canada and Wyoming, but remains relatively unmapped in Montana. The area of stratigraphic study is located at section 15, T36N, R5E Liberty County, Montana. This area located on Dafoe Ranch exhibits a moderately exposed stratigraphic section of Cretaceous Thermopolis Formation. The Bow Island Member lies between the Skull …