Earth Sciences Commons^™

The Nature And Origin Of Pebble Dikes And Associated Alteration: Tintic Mining District (Ag-Pb-Zn), Utah, Douglas M. Johnson

Theses and Dissertations

In many ore deposits throughout the world, brecciation often accompanies or occurs in association with mineralization (Sillitoe, 1985). Such is the case in the Tintic Mining District (Ag-Pb-Zn) of north-central Utah, where unique breccia features called pebble dikes occur alongside significant mineralization. Pebble dikes are tabular bodies of breccia, which consist of angular to rounded clasts of quartzite, shale, carbonate, and minor igneous rock cemented in a fine-grained clastic matrix. All clasts now lie above or adjacent to corresponding source rocks. Dikes are thin, typically less than 0.3 m wide to as much as 1 m, and can exceed 100 …

Carbon And Nitrogen Dynamics From Slow Pools Of Soil Organic Matter In A Temperate Forest: Pyrogenic Organic Matter And And Root Litter, Fernanda Dos Santos

Dissertations, Theses, and Capstone Projects

Soil organic matter (SOM) is the dominant reservoir of organic carbon (OC) in terrestrial ecosystems, storing approximately three times the size of the C pool in the atmosphere. In temperate forests, a major fraction of the SOM consists of slowly decaying soil organic C (SOC) pools. While slowly cycling C pools constitute a large reservoir of stable C in soils, the dominant environmental factors controlling this C pool remain unresolved. This research investigates two significant, but poorly characterized slowly decaying C pools: fine root litter (< 2mm) and thermally altered plant biomass (pyrogenic organic matter, PyOM). Specifically, I used compound-specific stable isotope analysis (¹³C and ¹⁵N) as my main methodological approach to examine the (1) …

The Late Quaternary Paleolimnology Of Lake Ontario, Ryan Hladyniuk

Electronic Thesis and Dissertation Repository

We examined the oxygen isotopic composition of biogenic carbonates, carbon and nitrogen abundances and isotopic compositions of bulk organic matter (OM), and the abundances and carbon isotopic compositions of individual n-alkanes (C₁₇ to C₃₅) for samples from three, 18 m long sediment cores from Lake Ontario in order to: (i) assess how changing environmental parameters affected the hydrologic history of Lake Ontario, and (ii) evaluate changes in organic productivity and sources since the last deglaciation. Knowledge of the hydrologic and ecological behaviour of the Lake Ontario basin during past climate change provides insight into its future …

Characterization Of Rain And Stormwater Nitrogen Inputs To The Mississippi Sound: A Landscape Approach, Joshua Michael Allen

Master's Theses

Urbanization in coastal watersheds is becoming an increasingly important issue in the world. Increased impervious surface cover, a factor of urbanization, has drawn more attention to stormwater runoff as a source of contamination to receiving waters. In this study, nitrogen species from rain and stormwater were analyzed across three different landscape types along the Mississippi Sound (hardened, residential, and pristine), as well as from drainage pipes that flow directly into to the Mississippi Sound. Nitrogen stable isotopes were used to trace the stormwater nitrogen to the surface waters and biota within the Sound.

The objective of this study was to …

Pore Water Extraction For Unsaturated Zone Isotope Research: An Investigation Using An Immiscible Displacement Fluid And A Centrifuge, Caitlin Burnett Weaver

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

Accurate and reliable pore water extraction techniques are important to an array of scientific fields including, but not limited to, hydrogeology, soil science, and paleoenvironmental research. The aim of the current project is to test the applicability of an immiscible displacement extraction technique for stable isotopes of water under a range of textural, hydrologic, and chemical conditions. In this study, laboratory experiments were conducted to establish the extent to which the proposed method 1) achieves sufficient yield for laboratory isotopic analyses, 2) results in isotopic exchange between water and the displacement fluid, 3) conserves initial isotopic compositions of spike test …

Groundwater Geochemistry Observations In Littoral Caves Of Mallorca (Western Mediterranean): Implications For Deposition Of Phreatic Overgrowths On Speleothems, Liana M. Boop, Bogdan P. Onac, Jonathan G. Wynn, Joan J. Fornós, Marta Rodríguez-Homar, Antoni Merino

International Journal of Speleology

Phreatic overgrowths on speleothems (POS) precipitate at the air-water interface in the littoral caves of Mallorca, Spain. Mainly composed of calcite, aragonite POS are also observed in specific locations. To characterize the geochemical environment of the brackish upper water column, water samples and salinity values were collected from water profiles (0-2.9 m) in April 2012 and March 2013 near aragonite POS in Cova des Pas de Vallgornera and calcite POS in Coves del Drac (hereafter, Vallgornera and Drac). Degassing of CO₂ from the water was evidenced by the existence of lower dissolved inorganic carbon (DIC) concentration and enriched δ …

Modern To Late Pleistocene Stable Isotope Climatology Of Alaska, Alison Sloat

UNLV Theses, Dissertations, Professional Papers, and Capstones

Understanding modern controls on climate is necessary to interpret past climatic conditions. This project investigated the modern controls on δ18O and δD values in Alaskan surface waters to interpret the controls on Late Pleistocene climate variability. ArcGIS was used to develop an isoscape of modern δ18O and δD values of over 400 surface water samples collected across Alaska and the Yukon. It was found that winter temperature and precipitation have the greatest controls on δ18O and δD values in Alaska, resulting in high δ18O values along the coast of the Gulf of Alaska and low values inland toward Central Alaska. …

Isotopic Fingerprinting Of Shallow And Deep Groundwaters In Southwestern Ontario And Its Applications To Abandoned Well Remediation, Mitchell E. Skuce

Electronic Thesis and Dissertation Repository

Abandoned hydrocarbon wells in southwestern Ontario can act as conduits for Sulphur water, brines, and hydrocarbons from deep Paleozoic bedrock aquifers. Such leakage may pose a threat to shallow groundwater and the environment. Cost-effective plugging of these wells requires knowledge of the sources of the leaking fluids. This study characterizes the isotopic compositions (δ18OH2O, δ2HH2O, δ34SSO4, δ18OSO4, δ13CDIC, 87Sr/86Sr) of groundwaters in the region, which are distinct in different bedrock formations. A Bayesian mixing model was applied to these data to develop a tool for identifying the source(s) of leaking fluids. The geochemical data also improve our understanding of groundwater …

Temporal And Spatial Characterization Of Macondo 252 Signatures In Gulf Of Mexico Shelf And Slope Sediments, Olivia P. Woodruff

Theses and Dissertations--Earth and Environmental Sciences

The long-term fate of hydrocarbons in the Gulf of Mexico (GOMx) following the 2010 Deepwater Horizon oil spill has yet to be fully characterized. Elemental (% C and % N), stable isotopes (δ¹³C_organic), and polycyclic aromatic hydrocarbon (PAH) molecular signatures were investigated in shelf and slope sediments collected in October 2010 and 2011 to gain insight into processes affecting the distribution and fate of spilled Macondo oil. Particulate organic carbon (POC) ranged between 1.55 and 2.22 wt. % in 2010 and 0.55 and 2.06 % in 2011 while the corresponding δ¹³C_organic ranges were …

Geology, Mineralogy, Geochemistry, And Depositional Environment Of A Late Miocene/Pliocene Fluviolacustrine Succession, Cappadocian Volcanic Province, Central Anatolia, Turkey, Ersel Göz, Selahatti̇n Kadi̇r, Ali̇ Gürel, Muhsi̇n Eren

Turkish Journal of Earth Sciences

This paper investigates the mineralogy, geochemistry, and depositional environment of Late Miocene/Pliocene fluviolacustrine deposits, including multiple ignimbrite levels and andesitic and basaltic lavas, within the Cappadocian Volcanic Province (CVP) of central Anatolia, Turkey. Palaeosols and calcretes formed within these terrestrial sedimentary rocks under near-surface or surface conditions. The palaeosols are composed predominantly of smectite ± illite with feldspar, quartz, calcite, opal-CT, and amphibole, and the calcretes mainly of calcite with minor feldspar, quartz, and accessory smectite ± palygorskite. The palygorskite occurs on and between the calcite crystals in the calcretes and at the edges of smectite flakes within the palaeosols, …

Untangling Earth System Responses Recorded In Sulfate's Sulfur And Oxygen Isotopes At The Dawn Of Multicellular Life And Today, Bryan Alan Killingsworth

LSU Doctoral Dissertations

Major Earth system perturbations in the deep past and today are recorded in sulfate sulfur and oxygen isotopes, as examined here in three cases. (1) Sedimentary sulfate record of the “Marinoan Oxygen-17 Depletion” (MOSD) event, implies ultra-high CO2 atmosphere at ~635 Ma after global glaciation. MOSD duration is constrained by correlating its most complete record to radiometric dates. Barium sulfate layers in South China sediments show the MOSD in lower layers but persistently absent up section. Carbon-13 correlation locates the MOSD within dated intervals from other sites, yielding a 0 - 0.99 Myr duration. Thus, sedimentary constraint on this non-steady-state …