Earth Sciences Commons^™

Trace Element Analysis Of Selected Springs In The Virgin River Basin, Mary A. Yelken

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spring water from 23 springs in and near the Virgin River Basin (southwestern Utah, northwestern Arizona, and southeastern Nevada) was collected and analyzed for chemical concentrations. Trace elements and major ion chemistry was used to determine the potential for utilizing water chemistry to provide information on spring water source and flow pathways. Principal Component Analysis (PCA), rare earth element (REE) normalization patterns, and mineral equilibrium modeling (PHREEQE) techniques were used to analyze the data set. Four major spring water groups were displayed by the PCA, based on similarities in water chemistry. The analyses suggest that spring water chemistry is a …

Synthetic Organic Compounds: Las Vegas Wash And Lake Mead, National Water Quality Assessment Program (Nawqa): Nevada Basin And Range

Publications (WR)

The Nevada Basin and Range (NVBR) study unit of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program is investigating the status of, trends in, and factors affecting water quality in the Las Vegas area. A principal objective of the investigation is to assess the effects of urbanization on the quality of area water resources. Las Vegas Wash is the surface-water outlet for the Las Vegas area. The wash transports stormwater runoff, shallow ground-water discharge, and tertiary-treated sewage effluent from the Las Vegas area to Las Vegas Bay of Lake Mead on the Colorado River. Most of the flow—about 96 …

Mafic Volcanism In The Colorado Plateau: Basin And Range Transition Zone, Hurricane, Utah, Alexander Sanchez

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Hurricane volcanic field (HVF) is a small-volume (0.48 km³) mafic volcanic field in the Colorado Plateau/Basin & Range Transition Zone located in the eastern part of the St. George basin in southwestern Utah. Strombolian-Hawaiian style eruptions produced thin (10 m) a'a lava flows and cinder (scoria) cones composed of vesicular basalt, bombs and agglutinate. Radiometric dating and geologic relationships demonstrate that the HVF formed over a period of at least 100,000 years. In the upper crust, magma probably rose along joints in sedimentary rocks because chains of volcanic vents follow joint orientation maxima in sedimentary rocks.

Three …

Tectonic Denudation Of Mesozoic Contractile Structures By A Low-Angle Normal Fault And Associated Faults, Southern White Pine Range, Nevada, Holly Langrock

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Blackrock Canyon area in the southern White Pine Range, Nevada mostly consists of the highly extended upper plate of a low-angle normal fault, the Blackrock fault. The post-31.3 Ma Blackrock fault places upper Paleozoic sedimentary rocks and overlying Tertiary volcanic rocks of the Garret Ranch Group in its hangingwall against a 50 degrees E-dipping homocline of Cambrian through Mississippian rocks in its footwall. The 15 to 30 degrees W-dipping Blackrock fault is non-planar and consists of two fault segments and a pronounced corrugation, the Bull Spring corrugation. These geometric irregularities suggest the slip direction on the fault was east-southeast …

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, …

An Understanding Of Factors Controlling Isotopic Ratios Of Wine As A Potential Surrogate Of Past Precipitation, Eric Alan Caldwell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Precipitation, vapor water, ground water, soil water, grape berry and grape leaf water, grape must, and vintage wines were collected from northern California for stable isotopic analysis. An understanding of factors controlling isotopic ratios of wine allows evaluation of wine as a surrogate of past precipitation. Stable isotopic compositions of grape berry waters collected at Charles Krug Winery in Napa Valley. CA range from -31 to -17 per mil in 8D and +7.2 to +15.3 per mil in 8180, and plot along a transpiration line of slope 2. 7. Grape leaf waters range from -25 to +5 per mil in …

Structural Analysis Of The Hurricane Fault In The Transition Zone Between The Basin And Range Province And The Colorado Plateau, Washington County, Utah, Meg E. Schramm

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study defines fault segments and segment boundaries along the Hurricane fault in southwestern Utah and determines the geometric and kinematic relationship to other regional structures. Fault segment identification is critical for understanding fault processes and seismic risk; segment length is the maximum earthquake rupture length along a fault. Segment boundaries may act as barriers to earthquake propagation.

Normal fault segmentation only recently has received attention and has never been studied along the Hurricane fault. The fault changes strike along its length, and is thus a segmented fault. This study documents one nonconservative segment boundary and two fault segments, the …

Spectral Analysis Of The Flow Behavior Of Big Spring, Kings Canyon National Park, California, Linda Urzendowski

UNLV Theses, Dissertations, Professional Papers, and Capstones

Big Spring, the resurgence of a karst aquifer in the Lilburn Cave system (Kings Canyon National Park, California), displays the uncommon phenomena of ebb and flow discharge during periods of high runoff.

Hydrograph analyses indicate that the portion of Lilburn Cave between the Z-Room and Big Spring is primarily a conduit flow aquifer. The power spectra strongly indicate a nonlinear system, with evidence of quasi-linear behavior found on a smaller scale. The transfer and kernel function indicate that no additional significant inputs or outputs to the system exist. The bench-scale model built to simulate the ebb and flow cycles in …

The Geology Of The Tuff Of Bridge Spring: Southern Nevada And Northwestern Arizona, Shirley Ann Morikawa

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Tuff of Bridge Spring (TBS) is a regionally-widespread, andesite to rhyolite (59.50 to 74.91 wt. %) ash-flow tuff of mid-Miocene age (ca. 15.2 Ma) that is exposed in the northern Colorado River extensional corridor of southern Nevada and northwestern Arizona. Determination of the areal distribution, geochronology, lithology, geochemistry, and internal stratigraphy of the TBS is important for its establishment as a reliable stratigraphic reference horizon for tectonic reconstructions of the extensional corridor during the middle Miocene. Based on reoccurring patterns of major and trace element variation, the TBS is divided into constant Cr/variable SiO₂ and variable Cr/variable SiO …

Depositional Environments And Paleoecology Of The Lower Ordovician Pogonip Group, Opd Unit, Arrow Canyon Range, Clark County, Nevada, Jeffrey K. Donovan

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Opd Unit of the Pogonip Group is a slope-forming carbonate sequence that crops out in the Arrow Canyon Range 75 miles north of Las Vegas, Nevada. It is composed mainly of grainstones, packstones, and intraformational conglomerates and also contains Calathium-bearing bioherms composed dominantly of wackestones. These rocks were deposited in a shallow-water, high-energy, subtidal, tropical marine environment. Nuia and Nuia-crinoid shoals developed on this shallow ramp and the area was frequently disturbed by storms.

Calathium-dominated carbonate mudmounds emerged on the Nuia and Nuia-crinoid shoals. Although Calathium dominated the mounds on a macroscopic scale, the mounds …

Desorption Hysteresis In Five Ion Exchanged Montmorillonites, Jerry Paul Fairley

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is generally believed that the formation of recalcitrant (slowly desorbing) fractions of volatile organic compounds (VOCs) in soils is due to diffusion of compounds to sorption sites inaccessible to bulk fluid. The exact nature of these sites, however, is not well understood. In clay minerals, researchers favor two probable areas for the storage of persistent contamination; sites between the clay lamella, or sites with clay particle aggregates.

To test the hypothesis that recalcitrant fractions are formed in interlamellar spaces, a Na/Ca Montmorillonite (Smectite) was ion exchanged with five different cations (K⁺, Na⁺, Ca⁺, …

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 …

Hydrogeology And Hydrogeochemistry Of The Shallow Alluvial Aquifer Zone, Las Vegas Valley, Nevada, Harry Stephen Wild Jr.

UNLV Theses, Dissertations, Professional Papers, and Capstones

In Las Vegas Valley, Nevada, the shallow alluvial aquifer zone is a possible source of contamination to the principal alluvial aquifers that provide 30% of the public drinking water supply for the valley. Development of the principal aquifers has lowered pressure head in the principal aquifers and created the potential for downward seepage from the shallow aquifer zone. This study was undertaken to characterize the hydrogeology and hydrogeochemistry of the shallow alluvial aquifer zone and to compare the hydrogeochemistry of the shallow and principal alluvial aquifer zones.

A 37 well shallow ground water monitoring network was established and water-level, water-quality, …

Stromatolites Of The Lower Cambrian Deep Spring Formation; Mount Dunfee, Esmeralda County, Nevada, Lynn Oliver

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Middle Member of the Lower Cambrian Deep Spring Formation at Mount Dunfee, Nevada contains a diverse assemblage of stromatolites that formed on a tide- and storm-dominated, siliciclastic-influenced, carbonate shelf. The stromatolites formed in a shallow subtidal environment within and near active oolite shoals under strongly focused currents. The stromatolites occur in four different lithofacies: (1) bioherms of digitate stromatolites, (2) bioherms and biostromes of inclined stromatolites, (3) isolated forms of massive and hemispheroidal stromatolites, and (4) a biostrome of cryptomicrobial boundstones. The first three lithofacies are interpreted as microbial reefs. They had topographic relief, formed in active agitated waters, …

Late-Holocene Earthflows Of The Willard Playa/Dune Complex, Estancia Valley, New Mexico: A Geomorphic Response To Climatic Change, Kurt A. Goebel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Late-middle to late Holocene dune sediment that overlies Pleistocene lacustrine sediment marks the onset of xeric conditions in the Estancia Valley, central New Mexico. Incised into the underlying lacustrine sediments, the modern deflation basins are enclosed by parabolic dunes composed of clay and gypsum derived from the underlying sediment.

Located on the in-facing dune slopes of the deflation basins, the most striking geomorphic feature of this dune complex are numerous elongated scars. These relict scars document a geomorphically distinct earthflow event. Arroyos that cut into flow scars expose eolian earthflow sediment overlying lacustrine deposits. In the zone of depletion, erosional-flow …

The Geology And Structural Significance Of The Arch Mountain Area, Northern Black Mountains, Mohave County, Arizona, Edward Eschner

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Arch Mountain area of northwestern Mohave County, Arizona, is typified by rocks that range from Precambrian to Quatemary in age. Arch mountain is a north-trending horst bounded on the west by the Petroglyph Wash graben and on the east by the Virgin Basin. A low-angle normal fault, herein named the Arch Mountain detachment fault, is exposed for 6 km along strike just below the ridge crest of Arch Mountain, and it is typified by a 2-20 cm thick zone of hematite-impregnated breccia and cataclasite. The detachment fault places an upper plate of Precambrian gneiss, Paleozoic quartzite, shale and dolomite, …

Spring Flow In A Portion Of Grand Canyon National Park, Arizona, David Bruce Goings

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hermit, Monument, Salt, and Horn Creeks flow through four side canyons of the Colorado River within the Grand Canyon. They lie just west of Grand Canyon Village on the south side of the canyon. Each of these creeks is fed by at least one spring.

Comparisons of flow at each of these springs for a 14 month period, and precipitation on the south rim show a close correlation. The lag period between recharge at the rim and discharge at the springs is less than one month for Hermit Creek and between one and two months for the other three creeks. …

Investigations And Research In Nevada By The Water Resources Division, U. S. Geological Survey, 1982-83, Terry Katzer, Otto Moosburner, William D. Nichols

Publications (WR)

The Water Resources Division, U.S. Geological Survey, is charged with (1) maintaining a hydrologic network in Nevada that provides information on the status of the State's water resources and (2) engaging in technical water-resources investigations that have a high degree of transferability. To meet these broad objections, 26 projects were active in Nevada during fiscal year 1982 in cooperation with 36 Federal, State, and local agencies. Total funds were $3,319,455, of which State and local cooperative funding amounted to $741,500 and Federal funding (comprised of Geological Survey Federal and cooperative programs plus funds from six other Federal agencies) amounted to …

An Ecological Analysis Of Relic Diatoms In Sediments Of Las Vegas Bay, Lake Mead, David Ross Hetzel

Publications (WR)

Relic diatoms in sediments of the inner Las Vegas Bay, near the Las Vegas Wash sewage inflow, were examined in order to assess historic trophic conditions in this area of Lake Mead. Diatom sedimentation rates and ratios of Araphidineae/Centrales (A/C) diatom groups were determined from sediment cores collected in the old wash channel 1.5 km from the sewage inflow (station 2), in a small cove 1.5 km further downstream (station 3) and in an adjacent embayment off Gypsum Wash (station 4). Diatom sedimentation rates generally increased from the bottom to the top of each core, but pronounced minima existed at …

Provenance And Description Of Landslide Masses, Rainbow Gardens Clark County, Nevada., Joseph R. Parolini

UNLV Theses, Dissertations, Professional Papers, and Capstones

A landslide breccia of plutonic and metamorphic rocks located 20 km east of Las Vegas, Nevada is interstratified with the late Tertiary Thumb Formation. Rock types of similar mineral composition to the landslide masses in the Rainbow Gardens are found 60 km to the east in the Gold Butte (Nevada) area. The landslide masses were displaced into their present position by lateral strike-slip motion along either the left-lateral Lake Mead fault system or the right-lateral Las Vegas shear zone. In t.he Rainbow Gardens landslide masses, five plutonic rock types, including rapakivi granite, match rocks from the Gold Butte area, both …

Provenance And Description Of Landslide Masses, Rainbow Gardens, Clark County, Nevada, Joseph R. Parolini

UNLV Theses, Dissertations, Professional Papers, and Capstones

A landslide breccia of plutonic and metamorphic rocks located 20 km east of Las Vegas, Nevada is interstratified with the late Tertiary Thumb Formation. Rock types of similar mineral composition to the landslide masses in the Rainbow Gardens are found 60 km to the east in the Gold Butte (Nevada) area. The landslide masses were displaced into their present position by lateral strike-slip motion along either the left-lateral Lake Mead fault system or the right-lateral Las Vegas shear zone. In the Rainbow Gardens landslide masses, five plutonic rock types, including Rapakivi granite, match rocks from the Gold Butte area, both …

Influence Of Las Vegas Wash Density Current On Nutrient Availability And Phytoplankton Growth In Lake Mead, John R. Baker, Larry J. Paulson

Publications (WR)

Density currents are commonly formed in reservoirs because of temperature or salinity induced density differences between inflowing and receiving waters. Anderson and Pritchard (1951) were among the first to demonstrate this in their investigations of density currents in Lake Mead. They found that the Colorado River formed an underflow in Lake Mead during the winter, an overflow in the spring and an interflow in the summer and fall. Wunderlich and Elder (1973) have since described the hydromechanics of these types of flow patterns, and density currents have been reported for several other large reservoirs (Carmack et al. 1979, Johnson and …

Final Report - Lake Mead Monitoring Program, James E. Deacon

Publications (WR)

The Lake Mead monitoring program has developed a substantial body of information on the physical, chemical and biological limnology of Lake Mead since 1972. This report summarizes pertinent aspects of that data, with emphasis on studies completed in 1975 -76. It is our continuing hope that the data developed by us will be useful to an ever broader group of users of the water resource represented by Lake Mead. We have been privileged to see our data have a significant influence in some very important water resource decisions over the past four years. There is every reason to expect that …

Geology And Ore Deposits Of The Johnnie District, Nye County, Nevada, Stanley Wayne Ivosevic

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Johnnie district, in the northwestern Spring Mountains, Nye County, Nevada, may have produced a little under 100,000 troy oz of gold, since the discovery of the district in 1890.

An approximately 13,000-ft-thick (4,000 m) section of east-dipping upper Precambrian through Middle Cambrian miogeosynclinal clastic and carbonate rocks is exposed in the district. The strata are, in order of decreasing age, the Johnnie Formation, Stirling Quartzite, Wood Canyon Formation, Zabriskie Quartzite, and Carrara and Bonanza King Formations. These are overlain by Cenozoic units which include and older unit and a younger unit of fanglomerate, the older containing a megabreccia deposit, …

Stratigraphic Comparison Of The Precambrian Wyman And Johnnie Formations In The Western Great Basin, California, Johnnie Nathan Moore

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Precambrian Johnnie Formation in the Death Valley area and to the south is separable into two facies. The southern facies contains six distinct members: the transitional, quartzite, lower carbonate-bearing, siltstone, upper carbonate-bearing, and Rainstorm members. Dolomite, quartzite, and mudstone characterize the southern facies, as does the presence of the Johnnie oolite. To the north the Johnnie oolite pinches out and the amount of mudstone in the formation increases. The dominantly mudstone northern facies contains local gray limestone lenses closely similar to limestone in the Wyman Formation in the White-Inyo Mountains. Generally outcrops of the northern facies of the Johnnie …

The Structural And Metamorphic History Of The Oakhurst Roof Pendant, Mariposa And Madera Counties, California, Lee R. Russell

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Oakhurst roof pendant, near Oakhurst, California, consists of three pre-Cretaceous clastic metasedimentary rock units, surrounded and intruded by rocks of the Sierra Nevada batholith. Two zones of probable "sheared granitic" and "ultramafic" rocks trend northwesterly and are approximately aligned with the Foothills fault system farther north.

The dominant mesocopic feature of the pendant is a northwesterly striking foliation which forms a downward converging fan. Earlier-formed hornblende lineations have been transposed into this foliation plane, as shown by Schmidt-net projections.

Rocks comprising the three unites show three textural stages:

1) Early amphiboles and diopside overgrown by later static amphibole pophyroblasts. …

Micronutrients And Biological Patterns In Lake Mead, Hasan K. Qashu, Lorne G. Everett, J. S. Carlson, Bureau Of Reclamation

Publications (WR)

Progressive increases in concentration of dissolved solids in the Colorado River water from Lake Powell to Imperial Dam seem to alter plankton dynamics and biological productivity of the river. Also, changes in biological productivity and micronutrients concentrations occur within the same reservoir. Development of a digital simulation model to predict micronutrients concentrations and biological productivity is necessary for diagnosing changes in plankton population and effluent-carrying capacity of the system. The objectives of the study are: (1) to determine trace metal balance at different locations in Lake Mead, (2) to measure biological productivity and conduct plankton population counts at each sampling …

The 1963-64 Lake Mead Survey, J. M. Lara, J. I. Sanders, Bureau Of Reclamation

Publications (WR)

The 1963-64 Lake Mead survey was run to compute the reservoir capacity. Results of the geodetic and hydrographic surveys and sediment sampling equipment are described. The geodetic survey showed Hoover Dam subsided an average of 118 mm since 1935. Sonic sounding, photogrammetry, and crosssectional profiling methods were used to run the hydrographic survey. Reservoir area and capacity tables were generated using an electronic computer. The present lake capacity is 29,755,000 acre-ft and the reservoir surface area is 162,700 acres at elevation 1229 ft. 2,720,000 acre-ft of sediments accumulated in the lake since 1935. A unit weight of 60 Ib/cu ft …