Geochemistry Commons^™

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 …

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 …

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 …

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 …