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Item Sedimentary tectonics of the Mesoproterozoic Lahood Formation, southwest Montana(Montana State University - Bozeman, College of Letters & Science, 2017) Fox, Nicholas Reid; Chairperson, Graduate Committee: David W. MogkThe LaHood Formation plays a critical role in constraining the sources and tectonic setting during the initial stages of formation of the Mesoproterozoic Belt Basin, particularly in the Helena Embayment. In the Bridger Range the LaHood Formation is composed of coarse conglomerates, lithic arkoses, calcareous shales and siliceous shales. Twelve measured stratigraphic sections show a general fining to the northeast with calcareous shales exposed only in the northern half of the Range. Lithology provides the basis for the LaHood Formation to be divided into three Members: A) conglomerate; B) lithic arkose and sandy micaceous shale; C) interbedded Member B with calcareous and siliceous shales that are interpreted as correlative rocks of the upper Newland Formation. U-Pb ages of detrital zircons (LA-ICP-MS) from four sandstones show: 1) The basal conglomerate and coarse arkosic facies in the lower and southern two sections have a primary age distribution at ~3.2 Ga with a minor ~3.5 Ga component that corresponds to the major TTG crust-forming event in the northern Wyoming Province; 2) zircons from an arkosic sandstone inter-fingered with calcareous shales have a dominant ~3.2 Ga signal, but includes a significant secondary concentration at 2.8 Ga, which corresponds to the age of the Beartooth-Bighorn Magmatic Zone; 3) the northernmost section exhibits a concentration near 3.2 Ga, a more significant ~2.8 Ga signal, and the first occurrence of ~1.8 Ga grains, indicative of the Great Falls Tectonic Zone. These detrital zircon ages confirm the results of Guerrero et al. (2015) in the Bridger Range and from LaHood exposures in the Horseshoe Hills to the west, but differ significantly from the dominant 3.4-3.5 Ga signal from LaHood exposures in Jefferson Canyon and north of Cardwell, MT (Ross and Villeneuve, 2003; Mueller et al., 2016). Collectively, the detrital zircon ages demonstrate a) occurrences of the LaHood Formation across the Belt Basin received sediment from temporally distinct sources that do not necessarily include proximal Archean basement, and b) the stratigraphic succession reflects contributions from progressively younger source areas. The significant variety of ages and abrupt facies changes in the LaHood Formation support a series of compartmentalized sub basins.Item An investigation of the reactions of supercritical CO 2 and brine with the Berea sandstone, muscovite, and iron bearing minerals(Montana State University - Bozeman, College of Letters & Science, 2015) Mangini, Seth Alexander; Chairperson, Graduate Committee: Mark L. SkidmoreThe reduction of anthropogenic CO 2 emissions while still generating energy is a challenge that society faces. Most current energy production comes from fossil fuels that increase atmospheric CO 2 concentrations. Pending a breakthrough in clean energy production, technological solutions that increase efficiency and sequester CO 2 are required. Carbon Capture and Storage (CCS) or carbon sequestration technology can provide part of the solution by providing disposal of point source CO 2 emissions. The research described in this thesis aims to aid development of CCS technology. There are three parts to the thesis. First, is an experimental study of the Berea sandstone to determine the reactivity of its minerals, as these could impact its potential as a reservoir for CO 2 storage. Cores of Berea were placed in a "flow-through reactor" that pumped a continuous stream of supercritical CO 2 (scCO 2) mixed with simulated groundwater through the rock. Chemical and physical changes to the solid, liquid and gas phases were monitored. Second, batch experiments were conducted to study the behavior of pyrite, magnetite, hematite, and muscovite when subjected to simulated groundwater and scCO 2. Third, is an outcrop study of the Devonian Jefferson Formation, a carbonate formation to serve as an analog to the same formation in the subsurface where it is the target of a Department of Energy CCS pilot project. The field study provided analysis of the mineralogy, sedimentology, and stratigraphy so as to better understand its potential as a reservoir for CO 2 storage. The flow-through experiments on the Berea sandstone demonstrated that carbonate cement and iron oxides were reactive phases. It was equivocal as to whether muscovite was reactive. The batch experiments quantified the reactivity of iron oxides and pyrite and demonstrated significant dissolution of the scCO 2, such that supercritical conditions were not maintained for the duration of the experiment. The batch experiments also showed that muscovite was not reactive within the time frame of the Berea flow-through experiments (72 hours), but was reactive over longer time periods (500+ hours). The field study indicated that the best potential reservoir zones of the Jefferson Formation are altered reef complexes composed mostly of dolomite.Item Depositional model of the sandstone beds in the Tongue River Member of the Fort Union Formation (Paleocene), Decker, Montana(Montana State University - Bozeman, College of Letters & Science, 1977) Widmayer, Margaret AnnItem Depositional environments and provenance of arkosic sandstone, Park shale, middle Cambrian, Bridger Range, southwestern Montana(Montana State University - Bozeman, College of Letters & Science, 1982) Fryxell, Jenny ChristineItem Evaluation of the multiple origins of thin-bedded deep-water slope sandstones : El Rosario Formation (Upper Cretaceous - Paleocene) Baja California, Mexico(Montana State University - Bozeman, College of Letters & Science, 2008) Ochoa Rodriguez, Jesus Armando; Chairperson, Graduate Committee: Michael H. GardnerOne dilemma in sedimentology is that multiple depositional processes can produce similar features while one formative process can generate multiple patterns. A comparison of (1) depositional energy trends from grain size and primary structures, (2) placement within a stratigraphic hierarchy, (3) ichnofacies type, diversity and distribution, and (4) sedimentary body type and associated architectural changes are used to assess the causal mechanism. Variations of these attributes reflect flow initiation processes (flood vs. failure), depositional processes (flow stripping, overspilling or bottom current reworking), and preservation (thin-beds bounded by erosional channels). Cretaceous and Tertiary outcrops in the Mesa San Carlos area expose four different thin-bedded sandstone types (TBS). This document presents a matrix of the most important attributes used to recognize them: (1) hyperpycnite successions (4-15m thick) are interbedded with slope mudstone deposits that together form tabular (85m thick; >1km wide) successions, with sandstone channels and scours common at the base and mass transport deposits present at the top, (2) Wedge-shaped TBS turbidites that flank and confine multistory channelbelts up to 90m thick that thin and pinch out within 500m of interdigitated but stacked conglomerate channels, (3) TBS turbidites separating channel bodies form 25m-thick and 230m-wide preserved remnants, and (4) TBS contourites comprising <3m wide sandstone lenses amalgamated laterally to form tabular bedsets. Paleocurrent indicators change from unidirectional offshore during hyperpycnal flow to slope parallel flow during waning energy conditions of this mudstone-rich cycle. The matrix allows for a sedimentological hierarchy that describes the spatial and temporal organization of hydrodynamic facies that link together to form sedimentation units recording changes in the longitudinal structure of the flow. Other results include the field- and lab-based mudstone analysis that allows recognition between hemipelagic and pelagic mudstones; the revision of the regional stratigraphy for the El Rosario Formation, and an energy matrix for hyperpycnite channels and scour deposits recording the downstream and vertical changes in sedimentary bodies, grain size and primary structures.Item Investigation of permeability patterns and diagenetic heterogeneity along the J-2 unconformity (UT, CO, AZ)(Montana State University - Bozeman, College of Letters & Science, 2011) Bechberger, Melody Ann; Chairperson, Graduate Committee: James G. Schmitt; David W. Mogk (co-chair)It is important to understand the variation in permeability along eolian bounding surfaces in subsurface eolian reservoirs for hydrocarbon recovery, CO 2 sequestration, aquifer management, and groundwater contaminant transport. The objectives of this investigation are to identify features associated with the J-2 unconformity and measure the range of permeability for each of these features. These features include dune lithofacies contacts, lag and reworked deposits, polygonal fracture networks, interdunes and paleowater tables. Petrographic image analysis, cathodoluminescence, x-ray diffraction and energy dispersive x-ray elemental analysis are used to characterize possible depositional and diagenetic influences on the range of permeability for each feature. J-2 dune facies are the most common and have a similar range in permeability to that shown by wind ripple laminations. Polygonal fracture networks can be weak or well developed and can be poorly to well cemented. Permeability variation in polygonal fracture networks is based on the intensity of cementation and would only significantly affect horizontal communication in a reservoir. Paleowater tables are generally well cemented, much like wet interdune deposits, and act as permeability barriers to fluid flow. Lag and reworked deposits are likely the result of sediment gravity flows generated either by topographic relief or from dunes bypassing on the incipient J-2 surface. Depending on the thickness and cementation of the lag and reworked deposits, these could act as significant permeability barriers and even generate stratigraphic traps. While permeability is reduced in many of these deposits by their depositional character, samples with ~5% cement generally have permeabilities that are 150mD or less and samples with more than 10% cement generally have permeabilities less than 10mD. Samples with this intensity of cementation are intensely concretionary, interdunes, paleowater tables, polygonal fractures, or reworked deposits.