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A Geological And Geochemical Study Of The Philipsburg Mining District, Granite County, Montana, Celine M. Beaucamp

Graduate Theses & Non-Theses

The Philipsburg district, renowned for its rich mining history, has contributed significantly to Montana's mineral production, ranking as the state's second-most productive district. Active from 1865 to the 1980s, it yielded an impressive array of Ag (50-60 million oz), with notable outputs of Au, Zn, Pb, Cu, and battery-grade MnO2. The district features Cordilleran polymetallic veins, some of which are along bedding in Mississippian and Devonian limestone, and others are steeply dipping quartz veins in silicate-rich sedimentary rocks and in the Philipsburg batholith. The veins exhibit a district-wide mineral zonation, marked by Cu- and Ag-rich ores near granite porphyries, with …

New Petrographic And Geochemical Constraints On Pre-Eruptive Storage Conditions And Their Control On Eruptive Styles In Martinique’S Recent Volcanic Systems, Abigail Martens

USF Tampa Graduate Theses and Dissertations

This dissertation investigates the volcanic systems of Martinique Island, focusing on magma storage conditions, magmatic evolution, and eruption dynamics. Chapter 3 presents a petrographic analysis of volcanic rocks from the island’s old, intermediate, and recent arcs, examining the evolution of plagioclase textures and the increasing abundance of other mineral phases, such as pyroxene, amphibole, olivine, and quartz, which provide insights into changing magmatic conditions. The main research is divided into two projects. Chapter 4 addresses the pre-eruptive storage conditions (pressure and temperature) of magmas beneath recent (<5 Ma) volcanic complexes (Morne Jacob, Piton du Carbet, Trois Îlets, Mt. Conil, and Mt. Pelée), exploring magma evolution, crystallization, and the role of lower crustal injections and flank collapses in triggering eruptions. Results reveal variable magma storage depths (<6 km), with significant temperature and pressure variations, indicating complex magmatic systems. Chapter 5 focuses on the Roches-Genty ignimbrite in southwestern Martinique, investigating its stratigraphy, geochemistry, and age using field mapping, grain size analysis, and 40Ar/39Ar dating. The study identifies two distinct sub-Plinian eruptive phases associated with the Dizac ignimbrite, with ages of 3.37 ± 0.14 Ma and 2.10 ± 0.26 Ma, providing insights into past explosive volcanic activity. Geochemical analysis confirms an andesitic composition, similar to regional volcanic systems. This dissertation enhances understanding of Martinique’s volcanic history, providing valuable insights into magmatic processes and eruption dynamics, with implications for volcanic hazard assessments in the Lesser Antilles.

Development Of A Low-Cost Tool For The Compositional Measurement Of Gases Derived From Mineral Water Wells From The Eastern Carpathians, Szalay Roland, Kis Boglárka-Mercedesz

Studia UBB Geologia

The Eastern Carpathians host CO₂-rich, low temperature, dry gas vents, bubbling pools and wells/drillings, which were established for the extraction of mineral water and CO₂ for the bottling industry. These wells can provide important information on the structure of the geological deposits, the depths, and the source of the gases, because they are often located at important geologic/tectonic sites. Our aim was to test the applicability of a hand-made and low-cost tool in preselected wells/drillings, in order to measure the concentration of different gas species. This was challenging due to the high water and gas discharge of …

Rock-Fluid Interaction And The Incorporation Of Cations Into Calcite During Recrystallization In Multiple Hydrothermal Systems., Van Anh Nguyen

Theses and Dissertations

Fluid-rock interaction causes an exchange of isotopes or elements through various reactions. The rate of these reactions strongly depends on temperature. The interaction involves dissolution precipitation, chemical exchange reactions, redox reactions, diffusion, and their combinations. The goal of studying fluid-rock interaction is to understand the change in mineral chemistry of the rock materials when in contact with an aqueous solution. These processes occur in all regions of the Earth where aqueous solutions are found. This work is comprised of three independent studies which provide an understanding about crystallization processes under multiple hydrothermal conditions with geological and environmental applications.

In the …

Geochemical And Industrial Properties Of The Kejal Kaolin Deposit, Nw Iran, Tohid Nouri, Rahim Masoumi

Turkish Journal of Earth Sciences

The Kejal kaolin deposit, situated in the northwest of Iran, is considered a small part of the Hashtjin hydrothermal zone. The kaolinization process in this deposit has occurred in ignimbritic and volcanic tuff parent rocks in different grades such that severely kaolinized samples can be found in the middle section of the kaolinization profile. Kaolinite is the most abundant clay mineral in the studied samples. Quartz and cristobalite are the main minerals while anatase is the minor mineral of the kaolin samples. Among the major oxides, SiO2, Al2O3, and TiO2 show the highest concentrations in kaolin samples. The mass change …

Mineralogical, Petrographic, And Geochemical Characterization Of Colored İscehisarmarbles (Afyonkarahisar, W-Turkey), Meti̇n Bağci

Turkish Journal of Earth Sciences

The İscehisar marbles are located 25 km northeast of Afyonkarahisar on the Ankara highway in the vicinity of the town of İscehisar. These marbles have economic importance in the Afyon region. The purpose of this study was to reveal the mineralogical, petrographic, and geochemical characteristics of the İscehisar marbles, displaying different colors, structures, textures, and other different features. Based on polarized light microscopy investigations, the İscehisar marbles can be classified into 3 subgroups: from bottom to top 1) calcitic marbles composed of calcite minerals, 2) transition/interlayer marbles, and 3) dolomitic marbles. According to the field descriptions, each subgroup has various …

U–Pb-Dated Flowstones Restrict South African Early Hominin Record To Dry Climate Phases, Robyn Pickering, Andy I.R. Herries, Jon D. Woodhead

KIP Articles

The Cradle of Humankind (Cradle) in South Africa preserves a rich collection of fossil hominins representing Australopithecus, Paranthropus and Homo1. The ages of these fossils are contentious2,3,4 and have compromised the degree to which the South African hominin record can be used to test hypotheses of human evolution. However, uranium–lead (U–Pb) analyses of horizontally bedded layers of calcium carbonate (flowstone) provide a potential opportunity to obtain a robust chronology5. Flowstones are ubiquitous cave features and provide a palaeoclimatic context, because they grow only during phases of increased effective precipitation6,7, ideally in closed caves. Here we show that flowstones from eight …

Geochemical Comparison Of Ancient And Modern Eolian Dune Foresets Using Principal Components Analysis, David A. Little

Theses and Dissertations

Geochemistry has been used to determine the provenance and diagenetic history of eolian sandstone deposits. However, the grain size, sorting, cementation, and detrital composition of eolian units can change along dune foreset laminae. The purpose of this study was to test for consistent trends of compositional change along dune foresets. Such trends could increase the quality of geochemical sampling of eolian sandstones and possibly aid in estimating the original height of ancient sand dunes. XRF data was gathered for both major and trace elements from the Pennsylvanian to Permian Weber Sandstone, Early Jurassic Navajo Sandstone, and modern Coral Pink Sand …

Geochemical And Petrological Characterizations Of Peridotite And Related Rocks In Marquette County, Michigan, Andrew Lloyd Sasso

Masters Theses

This study characterizes the following rock units in Marquette County, Michigan in terms of geochemistry and petrology: (1) Presque Isle Peridotite, (2) Deer Lake Peridotite, (3) Yellowdog Peridotite, and (4) Black Rock Point Gabbro. Analyses were conducted to determine if any petrological or geochemical relationships exist between these units, and to assess the potential of these units to host magmatic sulfide deposits.

The generated data and chosen geotectonic proxies indicate that Black Rock Point Gabbro and Deer Lake Peridotite crystallized from unrelated magmas, probably during the formation of the Great Lakes Tectonic Zone (2.7-1.85 Ga). No evidence was found which …

Carbon Cycling Dynamics Inferred From Carbon Isotope Sourcing In A Mid-Latitude Karst-Influenced River, Kegan N. Mcclanahan

Masters Theses & Specialist Projects

As ever-increasing levels of carbon dioxide alter the chemistry of the Earth’s atmosphere, understanding the global carbon cycle becomes increasingly important. A particularly important component is the riverine carbon cycle, as rivers are the primary conduits for dissolved inorganic carbon from terrestrial watersheds to ocean basins. Stable carbon isotopes (13C/12C) were collected weekly and input into the mixing model IsoSource to delineate seasonal carbon sourcing along two nested basins in the upper Green River System, Kentucky. In the more siliciclastic upstream catchment, dissolved inorganic carbon (DIC) was primarily derived from soil respiration (34%). Groundwater dissolving carbonate bedrock and carbonate dissolution/precipitation …

Petrologic And Geochemical Tracers Of Magmatic Movement In Volcanic Arc Systems: Case Studies From The Aleutian Islands And Kamchatka, Russia, Owen Kelly Neill

Geosciences

Mixing, crystallization and degassing commonly affect magmas during storage, ascent and eruption from volcanoes. As these interactions cannot be observed directly, they must be characterized using chemical signatures of volcanic eruptive products. In this dissertation, geochemical tracers of magma mixing, crystallization and degassing were employed to investigate the magmatic systems of Kasatochi Island volcano, central Aleutian Islands, and Bezymianny Volcano, Kamchatka, Russia, in three studies. The purpose of the first study was to characterize eruptive products from the 2008 eruption of Kasatochi Island volcano. This eruption produced pumiceous, medium-K andesite, as well as denser, medium-K basaltic andesite, with variable bulk …

Geochemistry Of Cave Pools In The Guadalupe Mountains, Nm : Implications For Geomicrobiology, Kooser Ara

Earth and Planetary Sciences ETDs

The study of the chemistry of waters in cave pools in the Guadalupe Mountains, NM was conducted to determine the variation in cave pool water geochemistry, explain hydrogeologic variations in a geologic context, identify the processes that control cave pool hydrologic variations and determine geochemical controls on modern and paleo-bacterial communities. Structural studies indicate cave pools align along NE and NW structures in the karst system. The intersection of Permian structures and Cenozoic related structures provide pathways for infiltrating water. Water samples were collected from 19 new cave pools; the results were integrated with published geochemistry from 192 cave pools, …

Temporal And Geochemical Insights Related To Volcanic And Plutonic Activity Within Big Bend National Park, Texas, Daniel Paul Miggins

Open Access Theses & Dissertations

Big Bend National Park located in the southeastern part of the Trans-Pecos Magmatic Province in west Texas contains a diverse suite of volcanic and intrusive rocks. Ongoing geologic mapping, geochronology, and geochemical studies have focused on the timing and geological relationships associated with these volcanic and intrusive rocks. Igneous activity within Big Bend National Park occurred from 46.5 to 22.0 Ma. Precise 40Ar/39Ar and U-Pb zircon geochronology has resolved the timing of this activity into five discrete episodes: 1) eruption and emplacement of both intrusive and volcanic mafic rocks at 46.5 Ma followed by ~42.0 Ma mafic volcanic pulse; 2) …

Petrogenesis And Geochemistry Of Pleistocene And Pliocene Basalt Flows Of The Pine Valley Volcanic Field, Utah And Their Relationship To The Tectonics Of The Utah Transition Zone, Matthew Faust

UNLV Retrospective Theses & Dissertations

The Pine Valley Volcanic Field in southwestern Utah consists of at least 24 mafic lava flows and 10 vents. Eruptions have spanned the past 2.4 m.y. The youngest eruptions at the Snow Canyon and Diamond Valley cones occurred between 1 and 20 ka. Lava flows range in composition from basalt to andesite, and include both alkaline and subalkaline rocks throughout the field. Trace element abundances for the youngest lavas show both oceanic island basalt (OIB) and mid-oceanic ridge basalt (MORB) components in their source. Sr and Nd isotopic ratios exhibit evolved values, spanning a large range from epsilon Nd of …

Lithium Isotope Geochemistry Of Marine Sediments., Libo Zhang

LSU Historical Dissertations and Theses

While the isotope geochemistry of lithium in the marine environment is increasingly known, there are still outstanding problems concerning its oceanic budget and mantle-crust recycling that remain to be resolved. To evaluate the role of marine sediments in the oceanic budget, laboratory experiments were conducted to determine the extent of lithium adsorption on marine sediments and the magnitude of isotopic fractionation. Sediments from the Greenland margin were studied to gain further understanding of the sediment-water interaction. The isotopic compositions of the major types of marine sediments were characterized to understand the sedimentary cycle of lithium. The enhanced database permits a …

Geology And Timing Of Zinc-Lead-Silver Mineralization, Northern Brooks Range, Alaska, Melanie Beth Werdon

Theses (Unassigned)

The north-central and northwestern Brooks Range of Alaska hosts widespread Carboniferous Zn-Pb-Ag +/- Ba shale-hosted massive sulfide (Sedex) deposits, and Zn-Pb-Ag +/- Cu vein-breccia and disseminated sulfide occurrences. The Sedex deposits are hosted by black carbonaceous shale and siliceous mudstone of the Mississippian to Pennsylvanian Kuna Formation and are spatially associated with minor (e.g. Red Dog) to locally abundant (e.g. Drenchwater) volcanic and hypabyssal intrusive rocks. The vein-breccia and disseminated sulfide occurrences show no obvious igneous association and are hosted by a deformed but only weakly metamorphosed package of Upper Devonian to Lower Mississippian mixed continental and marine elastic rocks …

Geochronology And Geochemistry Of The Basement Orthogneisses Of The Araguaia Belt, Brazil, Candido A Veloso Moura

Doctoral Dissertations

Orthogneisses representing the basement rocks of the Araguaia belt (AB), Brazil, are exposed in the core of dome-like structures. Gneisses of trondhjemitic, tonalitic, and granodioritic (TTG) composition constitute the Colmeia Complex, while augen gneiss, of granitic composition, is termed Cantao Gneiss (CG). An Archean age is suggested for the TTG gneisses, although the available Rb-Sr ages for these rocks range between 1.8 and 2.6 Ga. A Rb-Sr age of 1.77 Ga for the CG is interpreted either as a crystallization age or a resetting age.

Geochronological and geochemical studies of the orthogneisses of five of these dome-like structures of the …

The Sloan Sag: A Mid-Miocene Volcanotectonic Depression, North-Central Mccullough Mountains, Southern Nevada, Hayden L. Bridwell

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the Hidden Valley area of the north-central McCullough Mountains, southern Nevada, mid-Miocene andesite and dacite domes, flows and pyroclastic units (the Sloan volcanics) partially fill a sag in the underlying Hidden Valley volcanics. The 13.5 km diameter sag formed during and/or after the eruption of the Sloan volcanics. Sagging was accommodated by a combination of movement on the McCullough Wash fault system, and subsidence into evacuated chambers.

Major, trace and rare-earth element geochemistry suggests that the rocks of the Sloan volcanics belong to four groups, each of which were produced by partial melting of chemically distinct sources. With the …

Geochemical Exploration For Hidden Ore Deposits, D. H. Yardley

Journal of the Minnesota Academy of Science

No abstract provided.