Geochemistry Commons^™

Geochemical And Geochronological Constraints On The Tectonothermal History Of The Central And Eastern Nepal Himalaya: Implications For Thermal-Mechanical Models, Stacey Lynn Corrie

Boise State University Theses and Dissertations

Syntheses of Himalayan tectonics imply an average shortening rate of ~2 cm/yr across the Himalaya over the last 20-25 Myr. However, despite decades of research, basic questions still remain about how strain was partitioned. Fluctuations in the timing and rate of thrusting could have significant implications for strain partitioning across the Himalaya, and for partitioning during collisional orogenesis as a whole.

Due to the observed chronology and thermobarometry of Greater Himalayan Sequence (GHS) rock units in the Annapurna region of central Nepal, we revise the original interpretation of the Bhanuwa Fault from a normal fault to a thrust, and identify …

Petrogenesis Of The Greenwater Range: Comparison To The Crater Flat Volcanic Field And Implications For Hazard Assessment, Ashley Kaye Tibbetts

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pliocene basalts of the Greenwater Range, California erupted from 24 volcanic vents now represented by volcanic plugs, craters and scoria mounds. Basaltic magmas originated in the asthenospheric mantle, but show evidence of a lithospheric component. Depths and temperatures of melting calculated using a silica activity geobarometer are 54.3–89.6 km and 1367-1435oC, placing melting in the asthenosphere. The preferred petrogenetic model involves melting of lithospheric mantle thermally and mechanically, but not chemically, converted to asthenospheric mantle. Melting depths correspond to low velocity zones in the mantle as revealed in seismic profiles. Chemical and lithologic similarities between basalt in the Greenwater Range …

An Experimental Investigation Of Chemical Mass Transfer Processes In Crystallizing, Hydrous Silicate Magmas: The Genesis Of Ore Deposits And Metasomatic Fluids, Aaron S. Bell

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation is comprised of three broadly related experimental petrology projects on phase equilibria and noble metal solubility in hydrous silicate melts. Chapters two and three combine experimental petrology with high precision laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis of experimental run products in order to quantitatively constrain the behavior of the investigated metals. Chapter four presents experimental evidence detailing a novel oxidation mechanism for degassing silicate liquids as well as exploring the geochemical consequences of the proposed mechanism.

Chapter two presents the results of an experimental study on Au, Pt, and Pd behavior in coexisting silicate melt-sulfide-oxide …

Using Fluid Inclusions To Trace Formative Fluid Evolution At The Verde And Pancho Porphyry Au Deposits Of The Refugio District, Chile, Brian Joshua Aillaud

UNLV Theses, Dissertations, Professional Papers, and Capstones

Evolution of magmatically-derived formative fluids, and the processes that control the ratio of ore metals in porphyry and high-sulfidation epithermal deposits remain enigmatic. The Refugio district in the Maricunga Belt of Northern Chile hosts the temporally and spatially related Pancho and Verde porphyry gold deposits. Vein types at Pancho include A-veins, transitional veins, banded veins, D-veins and quartz-alunite ledges that formed by replacement. Verde East and West lack A-veins, and show an earliest vein type with transitional characteristics of A- to banded veins, banded veins and D-veins. Fluid inclusions and quartz textures were characterized by using optical microscopy and cathodoluminesence …

A Sequence Stratigraphic And Isotopic Study Of Uppermost Pennsylvanian–Lower Permian Carbonate Strata, Orogrande Basin, New Mexico, Jesse Koch

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Determining how the tropics respond to glaciation is important for improving our global understanding of icehouse worlds. The impetus behind this study is to identify the far-field impacts of Gondwanan glaciation during the Early Permian. Impacts including climate and sea-level change should be evident in sensitive carbonate systems, such as the upper Paleozoic paleotropical strata in the Orogrande Basin. A sequence stratigraphic and stable isotopic approach is used to examine the effects of late Paleozoic climate change in the Orogrande Basin during the acme and subsequent demise of the late Paleozoic ice age.

Sequence stratigraphic analysis suggests the occurrence of …

Geochemical Analysis Of Cenozoic Fossil Conifers At High Latitudes: Implications For Molecular Preservation And Environmental Change, Caitlyn Witkowski

Honors Projects in Science and Technology

Fossil materials record ancient life and their adapted environment. Arctic plant fossils are critical for our understanding of the Earth’s paleoenvironment when high latitudes were under ice-free conditions. All Arctic plant fossils in this research are conifers, plants conducive for morphological and molecular study because of their incredible genetic stability. Miocene (15 million year old) and Pliocene (5 million year old) conifer leaves were collected from Banks Island, Canada (Williams et al., 2008). Samples were analyzed and compared with Paleocene (60 million year old) and Eocene (45 million year old) samples from Axel Heiberg Island, Canada and with modern equivalent …

Detrital Zircon Geochronology For Neoproterozoic To Cambrian Sediment Sources Of The Deep Creek Range And The Pilot Range In The Southwestern United States, Kaysea Perry

Earth and Soil Sciences

Detrital zircon studies of miogeoclinal sediments can help provide a deeper look into the mechanisms leading to continental breakup by studying the evolution of the continental margin of North America. Few detrital zircon studies have been conducted to support previous research and theories about the sedimentation of the Miogeocline from the Neoproterozoic to the Cambrian. Studies targeted at the Basin and Range province of the western United States show a trend of increasing local sediment sources. We analyzed detrital zircons from the Pilot and Deep Creek Ranges in Nevada and Utah via LA-MC-ICP-MS at the University of Arizona LaserChron Center …

Comparison Of Carbon Stocks & Importance Values In Correlation With Past Land Use In The Gordon Natural Area, Timothy Hoffer, Steffen Lubbe

Forest Carbon Storage Study Documents

No abstract provided.

Forest Analysis Of The Gordon Natural Area Focusing On Carbon Stock, Forest Structure, And Forest Composition, R. Dicce, D. Drake, D. Mackey, P. Avery

Forest Carbon Storage Study Documents

No abstract provided.

Geochemical Investigation Of An Offshore Sewage Sludge Deposit, Barcelona, Catalonia, Spain, Michael A. Kruge, Albert Permanyer, Jordi Serra, Danlin Yu

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

For 20 years ending in the 1990’s the city of Barcelona discharged the products from a large primary sewage treatment plant directly into the Mediterranean Sea via underwater conduits. About ca. 3 million m³ of relict sewage sludge, rich in organic matter and heavy metals, has spread over an elongated area offshore, due to successive ruptures of the conduits. The use of the discharge pipes ceased, but he sludge deposit remains in place for the time being.

To understand the history and present state of the sludge deposit in advance of future remediation, a program of geophysical mapping, sampling, …

Mineralization In The San Juan Mountains, Colorado, William M. Sheriff

Open Access Theses & Dissertations

none

Hydrogeochemistry Of Caves Drip Water At Selected Caves In Peninsular Malaysia., Nor Bakhiah Baharim

Student Works (2010-2019)

This preliminary study represents the study on hydrogeochemical of caves drip water throughout Peninsular Malaysia. All samples were analysed for pH, Total Dissolved Solid (TDS), Dissolved Oxygen (DO), Conductivity, cation and anion. Despite local hydrological and geological differences among sampling sites, the monitoring revealed significant synchronous intersite variations that related to rainfall variation and control the volume of water input. The constant hydraulic pressure is expected in karst system as a result of moist condition of tropical region and rainfall throughout the year. Drip sites were classified into to two classifications which are seepages flow and seasonal flow. A simplified …

Lithium- And Oxygen- Isotope Profiles Of A Mid-Atlantic Ridge Oceanic Core Complex: The Atlantis Massif, 30°N, Ellen J. Crapster-Pregont

Honors Theses

Oxygen (O) and lithium (Li) are fluid-mobile elements used as geochemical tracers of a crustal component in the mantle. The isotopes of each element fractionate according to the degree and temperature of hydrothermal alteration. Previous studies demonstrate that Li and O isotopic trends are coupled within the upper crust near mid-ocean ridges but are decoupled in subduction-related volcanism. To better understand the average crustal signature of these systems, it is necessary to characterize these systems in the presently poorly understood lower oceanic crust. This study uses lower crustal samples from IODP Expedition 305 Hole U1309D exhumed at the Atlantis Massif, …

Late Permian Paleoenvironmental Factors Expounded Through Analysis Of A Forest-Floor Paleosol Profile, Karoo Basin, South Africa, Cassi Knight

Honors Theses

Beaufort Group paleosols from the Karoo Basin, South Africa, record the paleoenvironmental conditions that existed prior to and after the Permian-Triassic extinction event. Paleosol exposures from Wapadsberg Pass, Eastern Cape Province, represent a well- preserved forest-floor litter overlying an interpreted inceptisol, a condition unique to the basin. Vegetation that colonized this landscape included a canopy of the gymnosperm Glossopteris and an understory of sphenopsids (Phyllotheca and Trizygia). Wapadsberg Pass paleosol sites were sampled for petrographic and geochemical analyses to constrain interpretations of Late Permian paleoenvironmental conditions that existed ~ 70 m below the Permian-Triassic Boundary (PTB). This project focuses on …

A Seasonal Study Of Dissolved Cobalt In The Ross Sea, Antarctica: Micronutrient Behavior, Absence Of Scavenging, And Relationships With Zd, Cd, And P., M. A. Saito, T. J. Goepfert, A. E. Noble, E. M. Bertrand, Peter N. Sedwick, Giacomo R. Ditullio

OES Faculty Publications

We report the distribution of cobalt (Co) in the Ross Sea polynya during austral summer 2005-2006 and the following austral spring 2006. The vertical distribution of total dissolved Co (dCo) was similar to soluble reactive phosphate (PO(4)(3-)), with dCo and PO(4)(3-) showing a significant correlation throughout the water column (r(2) = 0.87, 164 samples). A strong seasonal signal for dCo was observed, with most spring samples having concentrations ranging from similar to ~ 45-85 pM, whereas summer dCo values were depleted below these levels by biological activity. Surface transect data from the summer cruise revealed concentrations at the low range …

Trace Metal Biogeochemistry In The Western North Pacific, Peter Lynn Morton

OES Theses and Dissertations

Dissolved and suspended particulate samples collected during the Intergovernmental Oceanographic Commission 2002 Contaminant Baseline Survey were analyzed to determine the surface and vertical distributions of Cd, Co, Cu, Mn, Ni Zn and Pb across the western and central North Pacific.

Dissolved trace metal concentrations were measured using a novel isotope dilution-ICP-MS method after extraction over an 8-hydroxyquinoline resin column and validated through the use of the SAFe consensus reference materials. Filtered suspended particulate matter was digested using an HCl/HNO3/HF mixture and analyzed by HR-ICP-MS to obtain total particulate concentrations for the trace metals and other tracer elements such as Al, …

Characterization Of Mantle/Crust Interactions Using Pb Isotope Analyses Of Lavas In The Southern Rio Grande Rift, New Mexico, Lynnette Crocker

Open Access Theses & Dissertations

The Pb isotope composition of volcanic rocks in the Rio Grande Rift (RGR) can be used to investigate the interaction of mantle melts with continental lithosphere, and has important implications for the composition of the lithosphere. We suggest some compositional signatures may pre-date current tectonic processes. Existing data from several volcanic fields in New Mexico show a converging pattern on a very limited Pb isotope range, corresponding to lower crustal xenolith compositions from Kilbourne Hole. The different volcanic fields show Pb isotope trends diverging from this lower crustal composition, likely depicting mixing with different upper crustal reservoirs. These very common, …

Application Of Copper And Zinc Isotopes To Fingerprint Metal Sources And Identify Attenuation Mechanisms In The Abandoned Waldorf Mine Area, Clear Creek County, Colorado, Suzan Aranda Luna

Open Access Theses & Dissertations

Acid rock drainage (ARD) is caused by the oxidative weathering of sulfide minerals. Sulfur is oxidized by dissolved oxygen or Fe(III) and sulfate ions, metals, and protons are released into the environment. Hence, the pH of nearby water and soils often decreases in response to ARD while metal concentrations increase. Because a large part of the Rocky Mountains of Colorado are highly mineralized (i.e., the Colorado Mineral Belt), ARD is a serious problem in this region. Moreover, the many abandoned mining areas in the Rocky Mountains that include waste rock piles, tailings impoundments, and surface disturbances add to the problem …

Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria, Jesica Urbina Navarrete

Open Access Theses & Dissertations

Copper isotopes may prove to be a useful tool for investigating bacteria-metal interactions recorded in natural waters, soils, and rocks. However, experimental data that constrain Cu isotope fractionation in biologic systems are limited and unclear. In this study we utilized Cu isotopes (65Cu) as a tool to investigate Cu-bacteria interactions, including surface adsorption and intracellular incorporation. Experiments were conducted with individual Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacterial species as well as with bacterial consortia from several natural environments. Adsorption experiments were conducted with live or dead cells over the pH range 2.5 to 6. Surface adsorption of Cu …

Granulometry And Geochemistry Of Dust Emission From Owens (Dry) Lake, California, Analila Rojo

Open Access Theses & Dissertations

Owens (dry) Lake, the terminus of Owens River, is located in the Basin and Range physiographic province in east–central California. The transformation of Owens Lake into a desiccated desert playa (approximately 280 km2) via diversion of the river into the Los Angeles Aqueduct (in 1913) led to extensive wind erosion, making the playa one of the most intense sources of airborne dust in the Western Hemisphere. The processes that direct the chemical and mineralogical composition of surface sediments at Owens (dry) Lake and the physical mechanisms of wind erosion, saltation and dust emission at Owens (dry) Lake are well–understood. However, …