Earth Sciences Commons^™

Identification Of Past Climate Variability Of The Eastern Pacific Ocean Using Both D13c And D18o Records In Corals From Clipperton Atoll (1994-1906), Lei Ren

Geology Theses and Dissertations

The ENSO (El Nino and the Southern Oscillation) is a fundamental ocean-atmosphere phenomenon that dominates interannual global climate variability. Reconstructing past ENSO events is therefore important for documenting and understanding the past behavior of the global climate system and enabling us to predict future climate change. However, the present understanding of ENSO events has been mainly based on the instrumental record of Pacific climate which provides detailed data only for the past few decades. Recent studies have shown that the stable isotope record in coral skeletons can be used as a valuable indicator of paleoclimatic changes in tropical regions, and …

A Geochemical Study Of Marine Sediments From The Mac. Robertson Shelf, East Antarctica: Initial Results And Palaeoenvironmental Implications, Peter N. Sedwick, P. T. Harris, L. G. Robertson, G. M. Mcmurtry, M. D. Cremer, P. Robinson

OES Faculty Publications

Sediments from the Antarctic continental margin may provide detailed palaeoenvironmental records for Antarctic shelf waters during the late Quaternary. Here we present results from a palaeoenvironmental study of two sediment cores recovered from the continental shelf off Mac. Robertson Land, East Antarctica. These gravity cores were collected approximately 90 km apart from locations on the inner and outer shelf. Both cores are apparently undisturbed sequences of diatom ooze mixed with fine, quartz-rich sand. Core stratigraphies have been established from radiocarbon analyses of bulk organic carbon. Down-core geochemical determinations include the lithogenic components Al and Fe, biogenic components opal and organic …

Effective Elastic Thickness Of The Lithosphere Along The Easter Seamount Chain, Sarah E. Kruse, Zhengro J. Liu, David F. Naar, Robert A. Duncan

Geology Faculty Publications

Bathymetry and gravity data collected during Legs 5, 6, and 7 of the 1993 GLORIA Expedition and the recently released 2-min altimetry-derived global gravity grid are used to determine the effective elastic thickness of the lithosphere along the Easter Seamount Chain (ESC). Forward modeling, admittance, and coherence methods yield consistent results. With the exception of the eastern and western ends of the ESC the effective elastic thickness along the chain is ∼1–4 km. The thin elastic thickness for the majority of the ESC seamounts is compatible with a young seafloor age at the time of loading derived from new radiometric …

Volcanology And Geochemistry Of Pliocene And Quaternary Basalts On Citadel Mountain, Lunar Crater Volcanic Field, Pancake Range, Nevada, Loretta D. Dickson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali basalts on Citadel Mountain form the southern margin of the Lunar Crater Volcanic Field (LCVF) in the central Great Basin, Nevada. Citadel Mountain comprised of a faulted, north tilted section of Tertiary andesite and ash-flow tuff is capped by Pliocene and Quaternary alkali basalt flows that erupted from six major cinder cones. The basalt flows on Citadel Mountain can be divided into two groups (older and younger) based on age and isotopic signatures. The older basalt group is characterized by higher ⁸⁷ Sr/⁸⁶Sr and lower E_Nd and the younger group has lower ⁸⁷Sr/⁸⁶Sr …

Microanalytical Investigations Of Gold-Bearing Rocks From The An Najadi Region In Saudi Arabia, Nazrul I. Khandaker, M. Ahmed, M. M. Hariri, M. A. Garwan, K. R. Khan, M. M. Al-Ohali

Publications and Research

The Proton Induced X-ray Emission technique with a scanning microbeam (micro-PIXE) and Scanning Electron Microscopy (SEM) were employed to study gold-bearing rocks from the An Najadi and adjacent regions situated within the exposed northeastern part of the Arabian Shield. These microanalytical investigations, together with routine petrological and ore microscopic studies, demonstrated the presence of important partitioning of major minerals and trace elements in several samples. These measurements also revealed microstructural features including brecciation within quartz grains and metal concentrations within these fracture-controlled micro-conduits. Results showed promise in terms of using distinctive geochemical signatures for ore body recognition. Of particular interest …

Estimation Of Groundwater Velocities From Yucca Flat To The Amargosa Desert Using Geochemistry And Environmental Isotopes, Ronald L. Hershey, Steve Y. Acheampong

Publications (WR)

Geochemical modeling techniques were applied to groundwater flowpaths from Yucca Flat on the Nevada Test Site (NTS) to the Amargosa Desert, south of the NTS to estimate groundwater flow velocities for independent comparison to velocities calculated by other methods. The groundwater flowpaths examined considered flow in the carbonate aquifer beneath Yucca and Frenchman flats mixing with flow from carbonate aquifers east and southeast of the NTS and discharging at wells south of the NTS border. The approach used the computer codes WATEQ4F and NETPATH to calculate chemical speciation, determine the saturation state of mineral phases, and simulate mixing and the …

Geochemistry, Stratigraphy And Provenance Of The Portland Hills Silt In The Tualatin Mountains, Portland, Oregon, John L. Lawes Iii

Dissertations and Theses

Soil morphology and geochemistry of loess were investigated at nine sites in the Tualatin Mountains west of Portland and at additional sites in The Dalles, eastern Washington and Puget Sound. A total of forty samples were examined using Instrumental Neutron Activation Analysis (INAA).

Stratigraphic relationships and soil development suggest that the PHS ages of Lentz (1977) be revised. The age of the Portland Hills Silt (PHS) ranges from 12,000 to at least 960,000 years before present.

The geochemistry of the PHS supports the Lentz (1977) hypothesis of the PHS as a loess of continental origin. Thorium/scandium ratios in the PHS …

Geochemical Characteristics And Correlations Within The Triassic-Jurassic Age Gabbs And Sunrise Formations Of West Central Nevada, Karen Elizabeth Boelling

Dissertations and Theses

Trace and minor element geochemistry was determined using Instrumental Neutron Activation Analysis for ninety-six (96) limestone and calcareous siltstone samples from four stratigraphic sections in the Triassic-Jurassic age Gabbs and Sunrise formations of west central Nevada. Geochemical data support lithologic and faunal interpretations of relative basin positions of the Sunrise Formation stratigraphic sections, as well as basin development (including transgressive­-regressive sequences) during deposition of the Gabbs and Sunrise formations at New York Canyon (Gabbs Valley Range). All sections show characteristics of both oceanic and continental island arc sources. Rare positive Eu anomalies relative to chondrites suggest that the Gabbs Formation …

Biostratigraphic Analysis Of Southern Florida's Plio-Pleistocene Shell Beds, Dalton L. Rasmussen

OES Theses and Dissertations

Four molluscan assemblage zones in southern Florida corresponding to the Pinecrest Sand Member of the Tamiami Formation, and the Caloosahatchee, Bermont and Fort Thompson shell beds were identified following quantitative and qualitative analyses of the fossil molluscan fauna. Twenty-eight bulk sediment samples collected from 16 localities across southern Florida were processed for fossil material, and yielded nearly 60,000 specimens belonging to 311 species. A Q-mode cluster analysis compared sediment samples on the basis of 188 species whose abundances had been converted to binary presence-absence form. The cluster analysis was run four times using the Jaccard and Dice similarity coefficients as …

The Effects Of Organic Matter Rich Topsoil On The Germination Growth And Metal Uptake Of Corn (Zea Mays) Grown In Flue Dust Contaminated Soil, Christopher Allen Impellitteri

OES Theses and Dissertations

The large biomass of corn (Zea mays) and promising results from a previous experiment (Chlopecka and Adriano, 1995) concerning metal uptake by corn indicate that corn may be a good candidate for phytoremediation of trace metal contaminated soil. Appling soil (acid, thermic, typic paleudult) was treated with increasing levels of a metal rich flue dust based on Zn concentration (0, 150, 300, 600, 1200, and 2400 mg/kg). Four replicates at each Zn treatment level were either limed to pH 6.3-6.5 and covered with a two inch thick layer of organic matter rich topsoil (OM), unlimed and covered with …

Application Of Environmental Organic Petrology And Geochemistry To Fingerprint Organic Pollutants In The Recent Sediments Of Lake Ontario, Prasanta K. Mukhopadhyay, Michael A. Kruge, C.F. Michael Lewis

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Selected surface sediment samples (sediment depth 0-10 cm) collected in the Niagara basin (western Lake Ontario) were chosen for organic matter characterization using organic petrological and geochemical techniques normally reserved for the study of coal, petroleum source rock and crude oil. The study was performed to assess the effectiveness of these techniques in discriminating between natural and anthropogenic organic matter and to determine the extent of organic pollution of the lake sediments. The organic carbon contents of the samples vary from 1.5 to 3.5%, with upper layer (0-5 cm) samples have higher TOC values than those from the lower layer …

Comparison Of Source Rock Geochemistry Of Selected Rocks From The Schei Point Group And Ringnes Formation, Sverdrup Basin, Arctic Canada, P. K. Mukhopadhyay, F. Goodarzi, Michael A. Kruge, M. H. Alimi

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Organic-rich from the Schei Point group (middle to late Triassic in age) and the Ringnes formation (late Jurassic) from the Sverdrup basin of the Canadian arctic archipelago have been geochemically evaluated for source rock characterization. Most samples from the Schei Point group are organic-rich (> 2% TOC) and are considered as immature to mature oil-prone source rocks [kerogen types I, I-II (IIA) and II (IIA)]. These kerogen types contain abundant AOM1, AOM2 and alginite (Tasmanales, Nostocopsis, Leiosphaeridia, acritarch and dinoflagellate) with variable amounts of vitrinite, inertinite and exinite. Samples from the Ringnes formation contain dominant vitrinite and inertinite …

Separation And Artificial Maturation Of Macerals From Type Ii Kerogen, Michael A. Kruge, Patrick Landais, David F. Bensley, B Artur Stankiewicz, Marcel Elie, Olivier Ruau

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Immature Type II kerogen (HI= 660 mg/g) from the Lower Toarcian of the Paris Basin was separated into an alginite concentrate (HI = 952 mg/g) and an amorphous organic matter (AOM) concentrate (HI = 573 mg/g) by density centrifugation. The flash pyrolyzate of the alginite is characterized by high relative concentrations of several series of n-alkanones and n-alkenones (including mid-chain alkyl ketones), in addition to n-alkanes, n-alk-1-enes and n-alkadienes. To our knowledge, this Toarcian alginite is the oldest example of marine organic matter whose pyrolyzate contains mid-chain alkanones in such high relative concentrations. In sharp …

The Petrogenesis Of Andesites Produced During Regional Extension: Examples From The Northern Mccullough Range, Nv And Xitle Volcano, Mexico, Kelly Ann Boland

UNLV Theses, Dissertations, Professional Papers, and Capstones

Andesite dominated volcanic systems produced during regional crustal extension remain a relatively unexplored aspect of andesite petrogenesis. In the southern Basin and Range province, thick sections of andesite and basaltic andesite have been documented in areas including the Piute Range, California, the Eldorado Range, Nevada, and the McCullough Range, Nevada. The northern McCullough Range, located 20 miles south-southeast of Las Vegas, is an ideal place to study the petrogenesis of an andesite dominated system. This area contains a mid-Miocene stratocone composed mainly of a 1200 m thick section of andesite flows that formed synchronous with regional extension.

The northern McCullough …

Prolonged History Of Silicic Peralkaline Volcanism In The Eastern Pacific Ocean, Wendy A. Bohrson, Mary R. Reid, Anita L. Grunder, Matthew Heizler, T. Mark Harrison, Jeffrey Lee

All Faculty Scholarship for the College of the Sciences

Socorro Island, Mexico, is an alkaline and peralkaline volcanic island located in the eastern Pacific Ocean on a mid-ocean ridge spreading center that was abandoned at ∼3.5 Ma. Silicic peralkaline rocks comprise up to 80% of the surface of the island, rendering Socorro virtually unique in the Pacific Ocean. Precise, replicate ⁴⁰Ar/³⁹Ar ages of 21 peralkaline trachytes and rhyolites reveal a history of episodic volcanic activity from ∼540 to 370 ka that may have culminated with caldera formation; repose periods between these episodes may have had maximum duration of ∼30 kyr. After up to 200 kyr of …

Residence Time Of Groundwater Issuing From The South Rim Aquifer In The Eastern Grand Canyon, Jim Fitzgerald

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the eastern Grand Canyon, secondary porosity created by north trending faults, folds, and breccia pipes, facilitates groundwater flow through the South Rim carbonate aquifer. Springs associated with the South Rim Aquifer have low ³H concentrations, [Ca²⁺]/[Mg²⁺] rations close to unity, and variable uranium concentrations. For a geochemical comparison, springs are subcategorized on the basis of geology and discharge. Type I springs are associated with high-angle normal faults and have high discharge rates. These springs discharge Ca²⁺ - Mg²⁺, HCO₃^- waters, have ³H concentrations <2 TR, and ²³⁴U/²³⁸U activity …

Study Of Volcanic Sediments By Microbeam-Pixe Technique, Nazrul I. Khandaker, M. Ahmed, M. A. Garwan

Publications and Research

Single mineral grains in a suite of Cretaceous (85–90 Ma) volcanic sedimentary rocks were analyzed using the microbeam-PIXE technique to understand fundamental geological processes responsible for micro-scale variation in elemental composition across mineral zones, twinning, cleavage planes, fractures and grain boundaries. Distributions of major and trace elements show distinct geochemical features indicative of a specific geological setting and a subsequent diagenetic process in these volcanic sediments. Examples of mineral zoning, microstructures of variable chemistry and post-depositional fluid flow are discussed using the data on feldspar group of minerals.

Artificial Maturation Of Alginite And Organic Groundmass Separated From Torbanites, Michael A. Kruge, Patrick Landais, David F. Bensley

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The two principal organic constituents — Botryococcus-related alginite and organic groundmass — were isolated by density separation from two torbanite samples (from the Stellarton Fm., Nova Scotia, Canada and the King Cannel, Utah, USA). The groundmass consisted of degraded algal, bacterial and terrestrial plant debris. Aliquots of alginite and groundmass were separately heated in gold tubes for 24 hr. with 70 MPa confining pressure, at fixed temperatures ranging between 250 and 375°C. The 250, 300 and 325°C experiments run on the alginite produced very low yields of CHCl3-extractable organic matter (EOM), indicating that very little of the generation potential …

Organic Geochemistry And Petrology Of Oil Source Rocks, Carpathian Overthrust Region, Southeastern Poland — Implications For Petroleum Generation, Michael A. Kruge, Maria Mastalerz, Andrzej Solecki, B Artur Stankiewicz

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The organic matter rich Oligocene Menilite black shales and mudstones are widely distributed in the Carpathian Overthrust region of southeastern Poland and have excellent hydrocarbon generation potential, according to TOC, Rock-Eval, and petrographic data. Extractable organic matter was characterized by an equable distribution of steranes by carbon number, by varying amounts of 28,30-dinor-hopane, 18α(H)-oleanane and by a distinctive group of C₂₄ ring-A degraded triterpanes. The Menilite samples ranged in maturity from pre-generative to mid-oil window levels, with the most mature in the southeastern portion of the study area. Carpathian petroleum samples from Campanian-Oligocene sandstone reservoirs were similar …

Flash Pyrolysis Of Anthropogenic And Natural Organic Matter In Polluted Sediments, Sami T. Abdel Bagi, Michael A. Kruge, Gary L. Salmon

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

INTRODUCTION - Combustion products along with spilled petroleum and industrial chemicals contribute to environmental degradation by contaminating soils and sediments. Such anthropogenic organic matter (OM), if preserved in sediments, can serve an archival function, documenting the local, history of industrial pollution. Christensen and Zhang (1993) determined the sources of polycyclic aromatic hydrocarbons (P AH) to Lake Michigan from sedimentary records, finding that coal combustion was a major source for PAHs in these sediments. Bodzek and Luks-Betlej (1993) reported that atmospheric deposition is the main source of PAH in soils of the heavily industrialized Upper Silesia region of Poland. Smith and …

Hydrogeology, Hydrogeochemistry, And Spoil Settlement At A Large Mine-Spoil Area In Eastern Kentucky: Star Fire Tract, David R. Wunsch, James S. Dinger, Page B. Taylor, Daniel I. Carey, C. Douglas R. Graham

Report of Investigations--KGS

An applied research program at the Star Fire surface mine in eastern Kentucky, owned and operated by Cypress-AMAX Coal Co., defined spoil characteristics to develop and monitor water resources, which will help identify a reliable water supply for future property development. Water stored in the mine spoil may provide a usable ground-water supply, and the spoil could also be engineered to provide base flow to surfacewater reservoirs.

Ground-water recharge enters the spoil by way of sinking streams, ground-water flow from bedrock in contact with the mine spoil, and a specially designed infiltration basin. Ground water discharges predominantly from springs and …

The Implications Of Turbidite-Driven Redox Changes In Sediments Of The Iberia Abyssal Plain, Timothy J. Shaw, P. A. Meyers

Faculty Publications

No abstract provided.

Organic Matter Accumulation, Sulfate Reduction, And Methanogenesis In Pliocene–Pleistocene Turbidites On The Iberia Abyssal Plain, P. A. Meyers, Timothy J. Shaw

Faculty Publications

No abstract provided.

Geology And Geochemistry Of Tertiary Volcanic Rocks In The Northern Reveille And Southern Pancake Ranges, Nye County, Nevada, Kelly Brian Rash

UNLV Theses, Dissertations, Professional Papers, and Capstones

The northern Reveille and southern Pancake Ranges, located in the south-central Great Basin, experienced a prolonged history of Tertiary volcanism. Volcanic activity in this area began with the eruption of large-volumes of ash-flow tuffs from calderas of the central Nevada caldera complex. The Reveille Range and the southernmost portion of the Pancake Range are the site of two calderas that are the sources for the tuff of Goblin Knobs and tuff of northern Reveille Range. The tuff of Goblin Knobs (70.4-75.3 wt.% SiO₂) erupted from the caldera of Goblin Knobs (25.6 Ma) and is the thickest (~1700 m) …

Geochemical Evolution Of A Mid-Miocene Synextensional Volcanic Complex: The Dolan Springs Volcanic Field, Northwestern Arizona, Scott Michael Mcdaniel

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Dolan Springs volcanic field (DSV), of northwestern Arizona, is dominated by andesite and basaltic-andesite flows and breccias, with minor amounts of basalt, rhyolite, and ash-flow tuff. Geochemistry is used here as a tool to evaluate the roles and contributions of the lithospheric and asthenospheric mantles to magmatism related to Miocene extension in the Colorado River extension corridor (CREC). The majority of synextensional volcanic rocks in the DSV are geochemically similar to regional trends, but rare tholeiitic basalts erupted near the end of extension. The tholeiites have trace element signatures similar to ocean island basalt (OIB), but have isotopic values …

A Petrographic And Fluid Inclusion Study Of The Purple Vein And Post/Betze Orebodies, Carlin, Nevada, Jan B. Lamb

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Purple Vein (Meikle Mine) and Post/Betze orebodies, two Carlin-type, gold deposits, display important differences in size, alteration, silicification, pyritization, and gold grade. A core hole was examined from each deposit to gather petrographic and microthermometric data to determine the mineral paragenesis, to determine fluid pressure, temperature, and composition to compare of the two orebodies, and to determine depths of formation.

The parageneses determined were divided into three stages. (1) The Early Mineralization Stage contains quartz, pyrobitumen, barite, sphalerite, sulfosalts, quartz, and pyrite in the Purple Vein deposit and consists of calcite in the Post/Betze deposit. High salinity basinal brines, …

Hydrogeochemical Delineation Of A Groundwater Flow System, Berrien County, Michigan, Patrick J. Bartnik

Masters Theses

The objective of this study was to examine the possibility of determining groundwater flow directions from natural variations in groundwater chemistry. Groundwater samples were analyzed for major cation and anion concentrations. These data were to have been contoured and then compared with groundwater flow maps generated by conventional methods. The purpose was to determine whether a correlation could be drawn between the two methods. However, the results of the study did not allow for this comparison.

The plotted major cation and anion data did not lend themselves to contouring, which suggests that greater control may be required during the selection …

Organic Facies And Maturation Of Jurassic/Cretaceous Rocks, And Possible Oil-Source Rock Correlation Based On Pyrolysis Of Asphaltenes, Scotian Basin, Canada, Prasanta K. Mukhopadhyay, John A. Wade, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

This paper establishes source rock characterization and oil-oil and oil-source rock correlations of selected organic-rich shale source rocks and selected light oils and condensates from Jurassic and Cretaceous formations of the Scotian Basin. Multiple source rocks of Kerogen Types IIA (oil-prone), IIA-IIB (oil- and condensate-prone), IIB (condensate and gas prone), III (gas-prone), and IV (nonsource) are identified in various stratigraphic horizons. Vitrinite reflectance and T_max data indicate variable maturation histories, in different parts of the basin, which are related to differences in lithology-related heat conductivity and the presence of older sediments closer to areas of rifting. Multiple linear regression …

Exposure Of A Food Crop To Trichloroethylene From A Contaminated Aquifer, Richard G. Baringer

Theses and Dissertations

This research developed a methodology for assessment of the exposure of a mature corn crop to trichloroethylene from a contaminated aquifer. The methodology was then applied to the case of Hill AFB to determine the ability of the methodology to provide information about a specific exposure. Current procedures sample for food contamination but do not attempt to predict exposure problems. A review of the potential exposure pathways from the aquifer to the crop was conducted. Based on this review, the exposures due to soil gas and irrigation were modeled. Empirical estimated were used to approximate the expected flux of soil …

Hydrogeology And Hydrogeochemistry Of Government Marsh, North St. Joseph County, Michigan, Michael C. Kasenow

Dissertations

A hydrogeologic and hydrogeochemical investigation was conducted at Government Marsh located in St. Joseph County, Michigan from May, 1988, to November, 1993. Information on glacial geology, topography, drainage patterns, hydraulic conductivity, vegetation, water chemistry, and static water table elevations has been collected and analyzed. Data were collected in order to determine directions of ground water flow and areas of recharge and discharge. Bail-down tests, grain-size analysis, and permeameters were used to determine hydraulic conductivity adjacent to and within the wetland. Water table elevations and chemistry were analyzed from wells adjacent to the wetland perimeter and within the boundaries of the …