Physical Sciences and Mathematics Commons^™

Seismic Analysis Of The 30 July 1972 Sitka Earthquake Aftershocks, Stress Drop Of Aftershocks In Cook Strait, New Zealand Following The 2013 Cook Strait And Lake Grassmere And 2016 Kaikoura Earthquakes, And 2d Seismic Tomography In The Brady Hot Springs Geothermal Site, Nevada, Juan Alejandro Ochoa Chavez

Open Access Theses & Dissertations

The 1972 Mw 7.6 Sitka earthquake is the largest earthquake to have occurred along the Alaska portion of the Queen Charlotte fault (QCF) in historic time. The QCF system forms the plate boundary between the Pacific and North American plates within southeastern Alaska and has accumulated enough slip since 1972 to produce a comparable sized event in the near future. Thus, it is important to better understand the controls on the rupture process of the 1972 mainshock and its aftershocks. Following the mainshock the U.S. Geological Survey installed a network of 11 portable seismographs that recorded over 200 aftershocks of …

Crustal Seismic Anisotropy Of The Ruby Mountains Core Complex And Surrounding Northern Basin And Range, Justin T. Wilgus

Earth and Planetary Sciences ETDs

Metamorphic core complexes (MCC) are distinctive uplifts that expose deeply exhumed and deformed crustal rocks due to localized extensional deformation. Consequently, their detailed structure provide a window into deep crustal mechanics. The North American Cordillera contains numerous MCC, one of which is the Ruby Mountains core complex (RMCC) located in the highly extended northern Basin and Range. To constrain the extent to which anisotropy below the RMCC deviates from the regional Basin and Range average and test the depth dependence of crustal anisotropy we conduct a radial anisotropy investigation below the RMCC and surrounding northern Basin and Range. Data from …

Structural Evolution And Regional Implications Of The Arrowhead Mine Fault Within The Pahranagat Shear Zone, Nevada, Usa, Michael Dennis Evans

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Basin and Range province is characterized by normal faults associated with

extension, but the occurrence of strike-slip faults and the seismic hazard accompanying

them is less understood. One major strike-slip zone, the Pahranagat shear zone (PSZ),

lies in Lincoln County, Nevada and within the boundary zone between northern Basin

and Range (NBR) and central Basin and Range (CBR) sub-provinces. The PSZ is a 20-

25 km long zone of Cenozoic left-lateral faults. The Arrowhead Mine Fault (AMF) is one

of the three major faults in the PSZ. The western AMF and the faults that surround and

abut it are …

Investigations On The Mesozoic Geologic And Tectonic History Of The Jackson Mountains, Northwest Nevada, Thomas Anthony Colby

Boise State University Theses and Dissertations

New geologic mapping, high-precision U-Pb zircon geochronology, and isotope geochemistry provide insight into the early Mesozoic paleogeography and magmatic, stratigraphic, and structural evolution of the Jackson Mountains in the Black Rock Desert region of northwest Nevada. The magmatic history of the Jackson Mountains records Late Triassic to Early Jurassic (~215-195 Ma) marine deposition of the Boulder Creek Beds adjacent to the arc followed by the Early Jurassic (~193-189 Ma) eruption and emplacement of the Happy Creek Igneous Complex and associated plutons of the Early Mesozoic Intrusive Suite. Pb, Sr, and Nd isotopic data from Early Jurassic intrusive rocks of the …

Controls On Fault Geometry During Early Stages Of Extension In The Larkspur Hills, Northwest Basin And Range, Diana Jean Strickley

All Master's Theses

Detailed analyses of normal faults in the Larkspur Hills, CA-NV, northwest Basin and Range, offer insight into factors controlling normal fault initiation, growth, and distribution. N-trending faults in the southern portion of the study area share trends of major range-bounding structures and Pliocene linear volcanic vents; in contrast, NNW- and NNE- trending faults dominate further north and into south-central Oregon. Stress analyses and comparison with experimental and field data suggest that preexisting structures control faults in the northern Larkspur Hills, while faults form perpendicular to σ3 in the southern hills. The change in fault orientations is abrupt, occurring across a …

Ichnology And Paleoecology Of The Jurassic Aztec Sandstone, Heather Marie Stoller

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this study I describe and interpret tracks and trackways of the Jurassic Aztec Sandstone of southern Nevada and southern California. This study involved mapping of all known tracks and trackways, including foot length, stride length, and trackway width. Photogrammetric data, collected by Bureau of Land Management scientists, were utilized for several trackways in Red Rock Canyon National Conservation Area.

More than three hundred tracks belonging to five ichnotaxa were documented within the Aztec Sandstone, including about 165 tridactylGrallator, 250 tetradactyl (four-toed)Brasilichniumtracks, and 7 arthropod trackways ofOctopodichnusandPaleohelcura. Four of the five ichnotaxa were not previously reported from the Aztec Sandstone. …

Paleoecology Of Late Pleistocene Megaherbivores: Stable Isotope Reconstruction Of Environment, Climate, And Response, Aubrey Mae Bonde

UNLV Theses, Dissertations, Professional Papers, and Capstones

Late Pleistocene megaherbivore communities of the Pacific and Mountain West states of California and Nevada are under-analyzed in regard to ecological function (diet, mobility, niche partitioning, and range of ecological tolerance). Stable isotope analysis is a powerful tool that is known to recover primary paleodiet and paleoenvironmental information from biogenic materials, such as enamel and dentin. This dissertation explores the use of carbon and oxygen stable isotopes in Late Pleistocene (40-10 Ka) megaherbivore teeth to gain a better understanding of inter- and intra-specific behavior and reconstruct Late Pleistocene ecosystems of California and Nevada. Radiocarbon dates exist for most of the …

Restoration Of Biological Soil Crust On Disturbed Gypsiferous Soils In Lake Mead National Recreation Area, Eastern Mojave Desert, Lindsay P. Chiquoine

UNLV Theses, Dissertations, Professional Papers, and Capstones

Biological soil crusts (BSCs) are sensitive to anthropogenic disturbances. Natural recovery takes many years. Active restoration decreases recovery time. Native BSC inocula, which included lichens and mosses, salvaged from gypsiferous soil habitats in Lake Mead National Recreation Area (LMNRA) in the eastern Mojave Desert were stored dry for two years and applied to disturbed soil after a road reconstruction in LMNRA and also used in laboratory experiments to test inoculation technique effectiveness. After 18 months, field results revealed positive relationships between inoculation and the presence of macroscopic BSC cover, cyanobacteria abundance, soil stability, and ammonium concentrations. Chlorophyll fluorescence monitoring of …

Volcanic Evolution Of The Southern Quinn Canyon Range: Implications For Regional Correlation Of Volcanic Units, Christina Emery

UNLV Theses, Dissertations, Professional Papers, and Capstones

The southern Quinn Canyon Range lies in an area of the Great Basin subjected to large-volume Oligocene-Miocene silicic volcanism and smaller volume basaltic volcanism during the Pliocene. Three major ash-flow tuff units were correlated in the southern Quinn Canyon Range (the Pahranagat Tuff, Clifford Spring Tuff, and the Cow Canyon Tuff) with regional units by utilizing U/Pb and 40 Ar/ 39Ar geochronology, geochemical correlation, and field mapping. Isotopic analysis suggests that basalt in the southern Quinn Canyon Range is part of the Death Valley-Pancake Range Basalt Zone and is similar to Reveille Range Episode 1 and 2 basalts. Further comparison …

Detrital Carbonates In A Sequence Stratigraphic Framework: An Example From The Furongian Slope Environment In The Hot Creek Range Of Central Nevada, Leon Taufani

UNLV Theses, Dissertations, Professional Papers, and Capstones

An integrated sedimentological study of detrital carbonates of the late Cambrian (Furongian) Hales Limestone in central Nevada was conducted in order to model facies distribution and controlling mechanisms of carbonate gravity-flow deposits. Seven closely-spaced sections and numerous traceable short sections were measured to investigate temporal and spatial changes of detrital carbonates within a high-resolution stratigraphic framework supported by biostratigraphic and carbon isotope chemostratigraphic constraints and by key physical surfaces. Polished slabs and thin section petrographic analysis were used to identify micro- and macro-scale textures and diagenesis.

Ten lithofacies are identified from the Hales Limestone. Lateral tracing of these facies reveals …

Paleoseismic Study Of The Stewart Valley And Northern Pahrump Segments Of The Stateline Fault System, Nevada, Jonathan Carter

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Stateline fault system (SFS) is a ~200 km long zone of dextral faults running NW along the NV/CA border from Primm, Nevada to Amargosa Valley in the western Central Basin and Range province (CBR). Because of size and proximity, the SFS poses a hazard to the 2.5 million people, most of who live within 10 km, in Pahrump, Nevada and within 40 km, in Las Vegas, Nevada. The goals of this thesis are to (1) understand if the SFS is accommodating faulting slip change in the CBR; (2) test the along strike continuity of the SFS in Pahrump and …

Muddy Creek Formation: A Record Of Late Neogene Tectonics And Sedimentation In Southern Nevada, Thomas William Muntean

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Late Neogene Muddy Creek Formation (MCF), exposed in the vicinity of Lake Mead in southern Nevada, represents the youngest widespread Cenozoic sedimentary sequence in the region and is the focus of this study. Historically, the MCF has been largely ignored, with limited previous studies providing only regional-scale constraint on the age, stratigraphy, and mode of deposition for the formation; resulting in a data gap for our understanding of the Late Cenozoic tectonic and sedimentological evolution of southern Nevada.

Burial And Exhumation History Of Mississippian Strata In East-Central Nevada, Yuki Yunika Agulia

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zircon (U-Th)/He analyses and vitrinite reflectance (Ro) analyses were performed on a suite of Mississippian sedimentary rocks collected in east-central Nevada in order to test Permian exhumation described in a previous study.

The zircon analyses produced three clusters of ages: 1) older than, 2) similar to, and 3) younger than depositional age. The majority of zircons shows ages that are older than the sandstone deposition age. Young ages were recorded in three localities that may indicate reset ages/residence within the (U-Th)/He partial retention zone (HePRZ). Moderate-high ratios of Th/U may indicate a magmatic source. Vitrinite reflectance (Ro) analyses show values …

Paired Positive Carbonate Carbon Isotope, Organic Carbon Isotope, And Oxygen Isotope Composition Study Across The Lower Mississippian Positive Carbon Isotope Excursion, Southeastern Nevada, Usa, Robert Alan Henry

UNLV Theses, Dissertations, Professional Papers, and Capstones

A prominent positive carbonate carbon isotope (delta13Ccarb) excursion of Early Mississippian age (ca 351 Ma) has been documented by previous studies from numerous sites globally. This delta13Ccarb excursion has been interpreted as resulting from enhanced organic carbon burial that removed 13C-depleted carbon from the ocean and atmosphere. Anticipated outcomes from enhanced organic carbon burial would include a similar positive excursion in organic carbon isotopes (delta13Corg) and a global cooling event resulting from reduced CO2 in the atmosphere and ocean. These predictions, however, were not tested sufficiently in previous studies. This research has tested these predictions through an integrated study of …

Geochronologic And Isotopic Investigation Of The Koipato Formation, Northwestern Great Basin, Nevada: Implications For Late Permian-Early Triassic Tectonics Along The Western U.S. Cordillera, Nicholas Quentin Vetz

Boise State University Theses and Dissertations

The volcanics of the Early Triassic Koipato Formation of central Nevada unconformably overlie the Golconda Allochthon and, classically, this relationship has been used to define the timing of the Sonoma Orogeny as post-Middle Permian to earliest Triassic. However, the Koipato Formation represents a rather isolated magmatic succession, with other western U.S. Early Mesozoic igneous provinces determined to be younger or lacking rocks of Koipato age. This isolation, coupled with the fact that the Koipato Formation does not overlap the Golconda Allochthon, has left open two possible scenarios for its tectonic history: 1) the Koipato Formation represents the earliest, post-Sonoma Orogeny …

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 …

Phyllosilicate Mineralogy, 40ar/39ar Geochronology, And Genesis Of Petrocalcic Soils In The Southwest U.S.A., Colin R. Robins

UNLV Theses, Dissertations, Professional Papers, and Capstones

Obtaining isotope ages for arid soils and paleosols, including carbonate-cemented (calcic and petrocalcic) horizons, constitutes a significant challenge for soil scientists, geomorphologists, and stratigraphers. Carbonate-cemented soils foster diverse suites of authigenic minerals with exciting potential for geochronology, however, this potential has not been realized. This dissertation describes the timing of pedogenic palygorskite and sepiolite crystallization in extremely old, extant petrocalcic soils of the southwest U.S.A., and assumes that these fibrous, high-magnesium phyllosilicates contain sufficient lattice-bound K to warrant vacuum-encapsulated 40Ar/39Ar geochronology. This three-part study evaluated the (1) selective extraction, (2) 40Ar/39Ar analysis, and (3) pedogenesis of palygorskite and sepiolite.

Effects …

Effects Of Plant Uptake And Micro-Topography On Chloride Transport In Arid Soils, Wenming Nie

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chloride concentration profiles to depths of 1 m were evaluated on a young alluvial fan in Eldorado Valley, NV. It was found that chloride beneath plant canopies were 11 to 222 times higher than adjacent (1 - 2 m away) bare soil locations. Two-dimensional numerical simulations using HYDRUS 2D/3D model were used to further explore the impact of plants on chloride transport. The simulation results indicated that lateral flow driven by root uptake concentrated chloride toward root zones, leading to the accumulation of chloride under plant canopies. Results also suggest that locally micro-topography can have a substantial impact on chloride …

Provenance Of The Miocene-Pliocene Muddy Creek Formation Near Mesquite, Nevada, Steven Wayne Forrester

UNLV Theses, Dissertations, Professional Papers, and Capstones

The provenance, stratigraphy, and depositional history of the Miocene-Pliocene Muddy Creek Formation (MCF) in southern Nevada are poorly studied and poorly constrained. Previous studies of the MCF have concluded that the formation consists of lacustrine, eolian, and fluvial deposits. Currently the age of deposition is loosely constrained between 8.5 and 4.1 Ma. This study documents the evolution of one portion of the eastern extent of the MCF and determines its provenance and depositional history at Flat Top and Mormon Mesas in Nevada; and near Beaver Dam and Littlefield, Arizona.

This study intended to determine whether the MCF was deposited by …

Petrogenesis Of Eocene-Oligocene Magmatism Of The Sulphur Springs Range, Central Nevada: The Role Of Magma Mixing, Elizabeth Balls Ryskamp

Theses and Dissertations

Widespread base- and precious-metal anomalies, altered porphyry intrusions and oxidized veins occur in a portion of the Sulphur Springs Range, Nevada (adjacent to the Au-producing Carlin Trend). Some of the Eocene-Oligocene intrusions and cogenetic volcanic rocks in the range exhibit evidence of magma mixing and invite comparisons with other mineralized, Eocene mixed magma systems like the Bingham porphyry Cu deposit 300 km farther to the east. The Sulphur Springs igneous suite ranges compositionally through rhyolite, dacite, andesite and basaltic andesite but is less alkaline than the Bingham volcanic suite. However, the alkali content of the Sulphur Springs suite is similar …

Structural And Geochemical Analyses Of Disseminated-Gold Deposits, Bald Mountain-Alligator Ridge District, Nevada: Insights Into Fault-Zone Architecture And Its Effect On Mineralization, K. Jill Hammond

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Structural and geochemical analyses of the Top and Casino deposits, Bald Mountain-Alligator Ridge district, Nevada, were conducted to determine how structures affected gold deposition in Carlin-type deposit s. We also examined how permeability changed over time in a fault that cuts siltstone-dominated sedimentary rocks. The association of gold and related arsenic with faults at the margins of a Jurassic pluton and sedimentary rocks suggests that ore fluids migrated along faults and fracture s. Permeability of the faults changed over time within the Casino deposit, where the ore-controlling fault was a distributed conduit in the early stages of mineralization but a …

Quaternary Amino Acid Geochronology Of The Lahontan Basin, Nevada, And The Chewaucan Basin, Oregon, Jeffrey Bigelow

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Amino acid geochronology based on fossil molluscs provides a useful approach to determining the Quaternary history of Great Basin lakes. The Lahontan basin, Nevada, and the Chewaucan basin, Oregon, in the northwest corner of the Great Basin, both contained lakes during the Quaternary. The aim of this study is to improve the Quaternary geochronology in these two basins by measuring time-dependent changes in amino acids preserved in fossil molluscan shells. The abundance of D-alloisoleucine relative to Lisoleucine (All) characterizes the extent of racemization, which increases with age and Ul forms the basis of relative and correlated ages. An age-calibration curve …

The Continuous Electrodeposition Of Manganese, Joseph W. Joyce

Bachelors Theses and Reports, 1928 - 1970

The object of this research was to produce a workable electrolytic cell for the continuous deposition of manganese from aqueous sulphate solutions and determine the critical factors in its oper­ation.