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Articles 271 - 300 of 850

Full-Text Articles in Geochemistry

“The Tale Of 3,000 Zircons”: An Investigation Of Grenville Sedimentation In Amazonia Using U/Pb Detrital Zircon Geochronology, Felicia R. Harris Jan 2020

“The Tale Of 3,000 Zircons”: An Investigation Of Grenville Sedimentation In Amazonia Using U/Pb Detrital Zircon Geochronology, Felicia R. Harris

Theses and Dissertations--Earth and Environmental Sciences

The continental collision between Laurentia and Amazonia that generated Rodinia and the Grenville Orogen is proposed to be one of the largest, hottest and longest-lived orogens in Earth history. Subsequent erosion and weathering led to a mountain range’s worth of sediment recycled into clastic systems across North America, otherwise known as the “Great Grenville Sedimentation Event”. The Sunsas orogeny in Amazonia is correlative to the Grenville in North America and is proposed to be the result of final Rodinian collision at 1200-1000 Ma. Despite the connection between the two ranges and the robust sedimentary record in North America, little work …


Altitude Of The Potentiometric Surface In The Mississippi River Valley Alluvial Aquifer, Spring 2018, Virginia L. Mcguire, Ronald C. Seanor, William H. Asquith, Anna M. Nottmeier, David C. Smith, Roland W. Tollett, Wade H. Kress, Kellan R. Strauch Jan 2020

Altitude Of The Potentiometric Surface In The Mississippi River Valley Alluvial Aquifer, Spring 2018, Virginia L. Mcguire, Ronald C. Seanor, William H. Asquith, Anna M. Nottmeier, David C. Smith, Roland W. Tollett, Wade H. Kress, Kellan R. Strauch

United States Geological Survey: Publications

The Mississippi River Valley alluvial (MRVA) aquifer is an important surficial aquifer in the Mississippi Alluvial Plain (MAP) area. The aquifer is generally considered to be an unconfined aquifer (fig. 1; Clark and others, 2011), and withdrawals are primarily used for irrigation (Maupin and Barber, 2005). These groundwater withdrawals have resulted in substantial areas of water-level decline in parts of the aquifer. Concerns about water-level declines and the sustainability of the MRVA aquifer have prompted the U.S. Geological Survey (USGS), as part of the USGS Water Availability and Use Science Program and with assistance from other Federal, State, and local …


Water Quality Of Groundwater Used For Public Supply In Principal Aquifers Of The Western United States, Celia C. Rosencrans, Marylynn Musgrove Jan 2020

Water Quality Of Groundwater Used For Public Supply In Principal Aquifers Of The Western United States, Celia C. Rosencrans, Marylynn Musgrove

United States Geological Survey: Publications

Groundwater provides nearly half of the Nation’s drinking water. As the Nation’s population grows, the importance of (and need for) high-quality drinking-water supplies increases. As part of a national-scale effort to assess groundwater quality in principal aquifers (PAs) that supply most of the groundwater used for public supply, the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Project staff sampled six principal aquifers in the western United States between 2013 and 2017: (1) the Basin and Range carbonate-rock aquifers, (2) Basin and Range basin-fill aquifers, (3) Rio Grande aquifer system, (4) High Plains aquifer, (5) Colorado Plateaus aquifers, and (6) Columbia …


Estimated Groundwater Withdrawals From Principal Aquifers In The United States, 2015, John K. Lovelace, Martha G. Nielsen, Amy L. Read, Chid J. Murphy, Molly A. Maupin Jan 2020

Estimated Groundwater Withdrawals From Principal Aquifers In The United States, 2015, John K. Lovelace, Martha G. Nielsen, Amy L. Read, Chid J. Murphy, Molly A. Maupin

United States Geological Survey: Publications

In 2015, about 84,600 million gallons per day (Mgal/d) of groundwater were withdrawn in the United States for various uses including public supply, self-supplied domestic, industrial, mining, thermoelectric power, aquaculture, livestock, and irrigation. Of this total, about 94 percent (79,200 Mgal/d) was withdrawn from principal aquifers, which are defined as regionally extensive aquifers or aquifer systems that have the potential to be used as sources of water of suitable quality and quantity to meet various needs. The remaining 6 percent (5,400 Mgal/d) was withdrawn from other, nonprincipal aquifers in the United States. Sixty-six principal aquifers belonging to 5 major lithologic …


Uranium Series Dating And Geochemistry Of Fault Zone Precipitated Secondary Carbonates: Insights Into Paleo Fluid Sources, Tectonics And Climate In The Rio Grande Rift, Victor Higareda Garcia Jan 2020

Uranium Series Dating And Geochemistry Of Fault Zone Precipitated Secondary Carbonates: Insights Into Paleo Fluid Sources, Tectonics And Climate In The Rio Grande Rift, Victor Higareda Garcia

Open Access Theses & Dissertations

Fault zones in the shallow crust impact a variety of geological processes including mineral deposition, fluid flow patterns in shallow and deep groundwater aquifers, and most importantly seismic activity. The specific interplays of fault zones, seismicity, and groundwater flows are complex and not well understood despite the importance they have to society. The Rio Grande rift is a region impacted by seismic and volcanic activity that place the first order control on mineral formation and fluid flow patterns. It is also a region that is often disregarded as a seismic hazard due to its inferred low tectonic rates and long …


A Multi-Method Investigation Of The Modern Sedimentation And Late Holocene Paleolimnology Of June Lake (Mono County, Ca), And A Survey-Based Analysis Of Ninth Graders’ Attitudes Towards Geology, Eva Lyon Jan 2020

A Multi-Method Investigation Of The Modern Sedimentation And Late Holocene Paleolimnology Of June Lake (Mono County, Ca), And A Survey-Based Analysis Of Ninth Graders’ Attitudes Towards Geology, Eva Lyon

Theses and Dissertations--Earth and Environmental Sciences

Three distinct manuscripts comprise this dissertation. The first analyzes the modern sedimentary basin of June Lake, a small glacial lake in the eastern Sierra Nevada of California (USA) using a number of data sets, including bathymetry, surface sediment composition, and seismic stratigraphy. The seismic survey revealed sublacustrine morphological features that suggest the basin originated due to ice scour, as well as four acoustically distinct stratigraphic units that reflect the history of sedimentation following glacial scouring. Corroborating the seismic record, sediment cores from the youngest unit are composed of hemipelagically deposited, organic-rich, laminated diatomaceous oozes alternating with coarse tephra beds. The …


Geochemical Flux Analysis Of Glacial River Runoff For Sólheimajökull, Iceland, Jessica Garrison Jan 2020

Geochemical Flux Analysis Of Glacial River Runoff For Sólheimajökull, Iceland, Jessica Garrison

Mahurin Honors College Capstone Experience/Thesis Projects

Geochemical fluxes in aqueous studies are an essential component of research to understand weathering and changes in a hydrologic system. These data can indicate any discrepancies, outliers, or gradual changes in a water environment to gain information on pollutants, carbon cycles, biological input, etc. Glacial melt is the majority of the surface water present throughout the country. The melting amount is increasing with the temperatures, which can be monitored by the changes in geochemical flux during increased discharge in glacial rivers. A high-resolution data set of Sόlheimajökull Glacier in Iceland was used to determine how changing climatic conditions for the …


Crystalline Architecture And Stratigraphy Of Coral Skeletal Density Banding: A Geobiological Record Of Changing Coral Reef Ecology, Kyle Fouke Jan 2020

Crystalline Architecture And Stratigraphy Of Coral Skeletal Density Banding: A Geobiological Record Of Changing Coral Reef Ecology, Kyle Fouke

Honors Theses

Coral skeletal density banding (CSDB), composed of alternating high density band (HDB) and low density band (LDB) layers that comprise the CaCO3 (aragonite) skeleton of scleractinian corals, are used as chronometers for global paleoclimatic reconstructions of sea surface temperature (SST). Scleractinian coral skeletons have been intensively studied for centuries with detail analysis of the macro- and microscale skeletal structure to establish taxonomic and evolutionary relationships of coral species, mechanisms of biomineralization, and seafloor physical, chemical and biological alteration (diagenesis) of the skeleton. This study is the first to determine the crystalline architecture of HDBs and CSDB stratigraphic …


Mineral Compositions Of Meteorite Samples Alha 77005, Nwa 7397, Nwa 5480, And Ausson: Implications For Geodynamic Processes On Their Parent Bodies And Meteorite Reclassification, Kaylin Agnata Tunnell Jan 2020

Mineral Compositions Of Meteorite Samples Alha 77005, Nwa 7397, Nwa 5480, And Ausson: Implications For Geodynamic Processes On Their Parent Bodies And Meteorite Reclassification, Kaylin Agnata Tunnell

Masters Theses

“This study investigates the major, minor, and trace element compositions of minerals from a series of meteorites which represent different stages of planetary evolution including two sample from Mars (ALHA 77005 and NWA 7397), one sample from Vesta (NWA 5480), and one ordinary chondrite (Ausson). The goal of this study is to investigate if petrogenetic tracers commonly employed to understand terrestrial samples can also be applied to extraterrestrial samples. The data presented here show that mineral trace element data allow for novel insight into the magmatic history of meteorite samples. For example, V/Sc and Fe/Mn ratios in olivine provide insight …


Applying Garnet And Zircon Ree Linkages To Determine Timing Of P-T Conditions And Tectonic Implications For Uhp Eclogites And Hp Granulites, Dulan Uhp Terrane, China, Wesley Weisberg Jan 2020

Applying Garnet And Zircon Ree Linkages To Determine Timing Of P-T Conditions And Tectonic Implications For Uhp Eclogites And Hp Granulites, Dulan Uhp Terrane, China, Wesley Weisberg

All Master's Theses

The Dulan ultrahigh-pressure (UHP) terrane in western China hosts rocks that record continental collision, however; the timing of peak P-T conditions in UHP eclogites and HP granulites, and the tectonic significance of their spatial relationship within the Dulan UHP terrane are not well understood. This study, (1) evaluates rare earth element (REE) equilibrium between garnet and zircon, to assess coeval growth; (2) links timing (from zircon) to the P-T history (from garnet) to constrain the P-T-t path of the Dulan UHP terrane and interpret implications for zircon growth; (3) refines P-T conditions for HP granulite; and (4) evaluates the tectonic …


Development Of A Synthesis Method For O2-Releasing Compound For Microbiological Experiments, Danae Greco Jan 2020

Development Of A Synthesis Method For O2-Releasing Compound For Microbiological Experiments, Danae Greco

Williams Honors College, Honors Research Projects

Many celestial bodies within our solar system may have habitable environments due to the presence of liquid water. Europa, one of Jupiter’s moons, may be habitable because of its liquid ocean and other potentially biologically favorable conditions. The ocean on Europa is hypothesized to contain large amounts of oxidants and low pH due to the radiolytically processed icy ocean shell. This suspected environment on Europa is similar to the composition of acid mine drainage on Earth, which can house microbial communities in environments of extreme acidity. Similar chemical reactions in Europa’s ocean may occur to produce the appropriate reduction-oxidation gradients …


Physical And Chemical Properties Of Clastic Sediments From Two Caves In The Northern Karst Region Of Puerto Rico, Autum R. Downey Jan 2020

Physical And Chemical Properties Of Clastic Sediments From Two Caves In The Northern Karst Region Of Puerto Rico, Autum R. Downey

Graduate Theses, Dissertations, and Problem Reports (ETD)

Geochemical properties and organic characteristics are essential to understanding the general depositional dynamics of a cave. Most work on clastic cave sediments focuses on physical properties of sediments. Little work has been done on bulk organic matter and geochemical properties.

This project reports physical and geochemical characterization of cave sediments from two caves in the northern karst region of Puerto Rico: El Tallonal Cave and Cueva Clara. Core and grab samples were collected and analyzed for particle size, total organic carbon, total nitrogen, organic matter characteristics using fluorescence spectroscopy, and major and minor elements using X-ray fluorescence (XRF). The sediments …


Recovering Lost Information From Avocational Projectile Point Collections, Mackenzie Hughes Jan 2020

Recovering Lost Information From Avocational Projectile Point Collections, Mackenzie Hughes

All Master's Theses

Human prehistory in North America has sparked the interest of private citizens for decades, sometimes leading to an accumulation of avocational artifact collections that lack site-level provenience. The Wild/Clymer artifacts (n = 1,371) are one such collection where precise site provenience was lost. The analysis aims to recover regional provenience by using morphology, raw material sourcing, and typology to create a data set. The avocational collection data set was analyzed by comparing it to the professionally recorded archaeological data sets from within 100 miles of Frenchglen, Oregon. A paradigmatic classification approach identified 606 typeable points in the avocational collection, in …


Model-Based Estimates Of The Timing Of Brine Flux Into The Victoria Land Basin From The Mcmurdo Dry Valleys, Antarctica, Valerie Nicole Voisin Jan 2020

Model-Based Estimates Of The Timing Of Brine Flux Into The Victoria Land Basin From The Mcmurdo Dry Valleys, Antarctica, Valerie Nicole Voisin

Graduate Research Theses & Dissertations

Submarine groundwater discharge (SGD) at a continental scale is one of the least constrained components of the hydrologic cycle and may represent a significant flux of iron and silica waters to the global ocean. Quantifying SGD along the Antarctic margin is complicated by complex subglacial and subsurface hydrogeology and limited observational data. Airborne transient electromagnetic (AEM) surveys have identified extensive high-salinity subsurface brines in the McMurdo Dry Valleys (MDV) that are hydrologically connected to surface features in the MDV (e.g. Taylor Glacier, saline lakes) and are potentially a significant source of SGD to McMurdo Sound. A 2D numerical model was …


Copper And Gold In Vapors And Liquids As A Function Of Hcl At 700°C And 100 Mpa, Corrie A. Lucchesi Jan 2020

Copper And Gold In Vapors And Liquids As A Function Of Hcl At 700°C And 100 Mpa, Corrie A. Lucchesi

Graduate Research Theses & Dissertations

Porphyry ore deposits are major sources of copper (Cu) and gold (Au) and form when a magmatic volatile phase (MVP) exsolves from a porphyritic intermediate to felsic melt and transports metals to surrounding country rock where they precipitate in an ore zone. There is a consensus that the chloride concentration of the MVP has a direct relationship to the concentration of Cu and Au in the MVP, but the role of dissolved HCl on Cu and Au concentrations has not been addressed. It is hypothesized that increasing HCl concentrations in the MVP will result in higher concentrations of Cu and …


History Of Natural And Anthropogenic Activities In Lake Izabal, Eastern Guatemala: Using Geochemical Evidence To Record Recent Contamination, Elisandra Hernandez Jan 2020

History Of Natural And Anthropogenic Activities In Lake Izabal, Eastern Guatemala: Using Geochemical Evidence To Record Recent Contamination, Elisandra Hernandez

Doctoral Dissertations

”Water is essential for human subsistence. Stable freshwater supplies are needed as a source of food, drinking water, for transportation, recreation and economic development. Despite their recognized importance, anthropogenic activities have altered freshwater ecosystems around the world. Lake Izabal is the habitat for diverse aquatic species of flora and fauna, some of which are endemic and endangered. Its importance notwithstanding, anthropogenic activities developed in Lake Izabal’s catchment in recent years have compromised its status. This study used paleolimnological techniques to link past and recent anthropogenic activities such as mining operations and recent tilapia aquaculture. Relative abundances and concentrations of Pb, …


Anatomy Of The Magmatic Plumbing System Of Los Humeros Caldera (Mexico): Implications For Geothermal Systems., Federico Lucci, Gerardo Carrasco-Nuñez, Federico Rossetti, Thomas Theye, John C. White, Stefano Urbani, Hossein Azzizi, Yosihiro Asahara, Guido Giordano Jan 2020

Anatomy Of The Magmatic Plumbing System Of Los Humeros Caldera (Mexico): Implications For Geothermal Systems., Federico Lucci, Gerardo Carrasco-Nuñez, Federico Rossetti, Thomas Theye, John C. White, Stefano Urbani, Hossein Azzizi, Yosihiro Asahara, Guido Giordano

EKU Faculty and Staff Scholarship

Understanding the anatomy of magma plumbing systems of active volcanoes is essential not only for unraveling magma dynamics and eruptive behaviors but also to define the geometry, depth, and temperature of the heat sources for geothermal exploration. The Pleistocene–Holocene Los Humeros volcanic complex is part of the eastern Trans- Mexican Volcanic Belt (central Mexico), and it constitutes one of the most important exploited geothermal fields in Mexico with ca. 90MWof produced electricity. With the aim to decipher the anatomy (geometry and structure) of the magmatic plumbing system feeding the geothermal field at Los Humeros, we carried out a field-based petrological …


Groundwater Investigations To Support Irrigated Agriculture At La Grange, Western Australia: 2013–18 Results, Robert J. Paul, Gregory Paul Raper, Richard J. George Dr, Nicholas J. Wright, Adam M. Lillicrap, Peter S. Gardiner Dec 2019

Groundwater Investigations To Support Irrigated Agriculture At La Grange, Western Australia: 2013–18 Results, Robert J. Paul, Gregory Paul Raper, Richard J. George Dr, Nicholas J. Wright, Adam M. Lillicrap, Peter S. Gardiner

Resource management technical reports

The Broome Sandstone aquifer is the main aquifer and groundwater resource in the La Grange area, near Broome in the West Kimberley, Western Australia. Land use is dominated by cattle grazing on pastoral stations, dispersed mining and tourism. Irrigated agriculture has developed at a small scale, with about 470 hectares under cultivation in 2014. Groundwater abstraction is licensed under the La Grange groundwater allocation plan (Department of Water 2010) and managed by the Department of Water and Environmental Regulation. The La Grange groundwater allocation area is split into the La Grange North subarea and La Grange South subarea, with groundwater …


A Granger Causality Analysis Of Groundwater Patterns Over A Half-Century, Nitin K. Singh, David M. Borrok Dec 2019

A Granger Causality Analysis Of Groundwater Patterns Over A Half-Century, Nitin K. Singh, David M. Borrok

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Groundwater depletion in many areas of the world has been broadly attributed to irrigation. However, more formal, data-driven, causal mechanisms of long-term groundwater patterns have not been assessed. Here, we conducted the first Granger causality analysis to identify the "causes" of groundwater patterns using the rice-producing parishes of Louisiana, USA, as an example. Trend analysis showed a decline of up to 6 m in groundwater level over 51 years. We found that no single cause explained groundwater patterns for all parishes. Causal linkages were noted between groundwater and area harvested, number of irrigation wells, summer precipitation totals, and drought. Bi-directional …


Characterizing Hydrothermal System Groundwater Dynamics Using Conservative And Non-Conservative Tracers: Insights And Implications Drawn From Study At The Taupo Volcanic Zone (New Zealand) And Valles Caldera (Usa), Joshua Michael Blackstock Dec 2019

Characterizing Hydrothermal System Groundwater Dynamics Using Conservative And Non-Conservative Tracers: Insights And Implications Drawn From Study At The Taupo Volcanic Zone (New Zealand) And Valles Caldera (Usa), Joshua Michael Blackstock

Graduate Theses and Dissertations

Hydrothermal systems constitute an important component of heat and mass transport within Earth’s crust having direct and indirect impacts to society. Investigating contemporary hydrochemical differences and change are critical to evaluating and deconvolving factors that influence geothermal systems through time. In this dissertation, groundwater mixing approaches were used to study hydrochemical differences in two globally significant hydrothermal areas, which included fabrication of a low-cost dissolved CO2 monitoring for dissolved inorganic carbon (DIC). In the Taupo Volcanic Zone (New Zealand), empirical spatial relations were used to derive low-temperature groundwater end-members of Cl and Cl/Br for end-member mixing analysis (EMMA). Using EMMA, …


Evidence Of Variable Climate And Resources During The Late Pleistocene And Holocene At Gona, Ethiopia, Marie White Nov 2019

Evidence Of Variable Climate And Resources During The Late Pleistocene And Holocene At Gona, Ethiopia, Marie White

Steeplechase: An ORCA Student Journal

The African Humid Period (AHP) spanned a period of approximately 15 to 5 thousand years ago (ka) and resulted in Northern and Eastern Africa being wetter than today. This climate change event impacted flora, fauna, and humans to an unknown extent. Much of the work on the AHP across Eastern Africa utilizes lacustrine and marine proxies rather than river-based (fluvial). Gona, located in the Afar region of Ethiopia, is known for its extensive archaeological and fossil records in fluvial deposits. However, the paleoenvironment of the AHP at Gona has not been investigated. This study uses stratigraphy, geochronology, and paleopedology to …


Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero Nov 2019

Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero

LSU Master's Theses

A provenance study of quartz arenites that stratigraphically are closely associated with major Ordovician K-bentonites has been conducted in order to further our understanding of the tectonic setting of eastern Laurentia during the Late Ordovician. Using laser ablation ICP-MS, detrital zircons separated from Ordovician sandstone samples in the southeastern Appalachian Mountains (Virginia to Alabama) were dated using U-Pb geochronology. Analytical results show three dominate age ranges for the zircons from these sandstones: ~440-490 Ma, ~900-1300 Ma, and ~1300-1500 Ma. In addition, some zircon ages grouped into older ranges of ~1600-1800 Ma, ~1800-1900 Ma, and ~2600-2800 Ma. Zircon ages from ~900-2800 …


Boron Variation And The Subducted Sediment Component In The Volcanics From The Bifurcated Portion Of The Lesser Antilles Island Arc (Laia), Ami Margret Ngo Ward Nov 2019

Boron Variation And The Subducted Sediment Component In The Volcanics From The Bifurcated Portion Of The Lesser Antilles Island Arc (Laia), Ami Margret Ngo Ward

USF Tampa Graduate Theses and Dissertations

North of Martinique island the Lesser Antilles volcanic arc bifurcates, creating a double arc. Here volcanic activity has migrated up to 50 km westward with time, resulting in two volcanic lines that are distinct in age. The eastern line, commonly referred to as the old arc, was active from Early Eocene to Mid-Miocene (Nagle, 1971; Nagle et al., 1976; Westercamp and Tazieff, 1980; Andreieff et al., 1988). The western line, commonly referred to as the recent arc, has been active since the late Pliocene, ~6 Ma ago (Nagle, 1971; Nagle et al., 1976; Westercamp and Tazieff, 1980; Andreieff et al., …


Neogene Chemical Weathering And Provenance Records Of The Western Himalaya Preserved In The Arabian Sea, Peng Zhou Oct 2019

Neogene Chemical Weathering And Provenance Records Of The Western Himalaya Preserved In The Arabian Sea, Peng Zhou

LSU Doctoral Dissertations

Some tectonic models for the Himalaya emphasize the importance of surface processes in controlling the structural evolution. To investigate this tectonic–climatic interactions, and the weathering and erosion of the western Himalaya, International Ocean Discovery Program (IODP) Expedition 355 drilled two sites (site U1456 and U1457) in Laxmi Basin, which located in the Eastern Arabian Sea. In my research project, I plan to use a series of geochemical and geochronological methods on the sediment samples from the cores of these two sites, and sediments from an industrial borehole Indus Marine A-1, which near the Indus river mouth, to reconstruct a climatic …


A Terrestrial Reconstruction Of Gona, Ethiopia Before And During The African Humid Period, Marie N. White, Gary E. Stinchcomb Oct 2019

A Terrestrial Reconstruction Of Gona, Ethiopia Before And During The African Humid Period, Marie N. White, Gary E. Stinchcomb

Posters-at-the-Capitol

The African Humid Period (AHP) resulted in more humid conditions across Northern and Eastern Africa from 15 to 5 thousand years ago (ka). This wetter climate affected flora, fauna and the Homo sapiens living in East Africa. The lack of terrestrial paleoenvironmental reconstructions is a problem in East Africa, especially during the AHP, where most are done utilizing lacustrine or marine proxies. In the case of Gona, Ethiopia, terrestrial proxies are desired due to the rich archaeological and fossil concentrations that occur in the area. Paleosols provide more direct, localized reconstructions that provide context for these finds. This study utilizes …


On The Ablation Of Meteors And The Implications On Organic Delivery To Earth, Christopher Alan Mehta Oct 2019

On The Ablation Of Meteors And The Implications On Organic Delivery To Earth, Christopher Alan Mehta

USF Tampa Graduate Theses and Dissertations

The synthesis of prebiotic organic compounds is a key step in the origin of life. Sources of these materials are divided into endogenous and exogenous sources. Endogenous synthesis—occurring potentially on the surface of the Earth—includes such historic experiments as the Miller spark discharge and formose chemistry. However, one avenue for exogenous synthesis to occur is when meteors enters an atmosphere. Using principles of orbital mechanics, geology, physics, and chemistry, we study meteor ablation and the transport of organic matter to the surface of Earth. To do so, I create numerical models that simulates meteors traveling through the atmosphere of Earth …


Influence Of Spring Flow Reversals On Cave Dissolution In A Telogenetic Karst Aquifer, Mammoth Cave, Ky, Chelsey Kipper Oct 2019

Influence Of Spring Flow Reversals On Cave Dissolution In A Telogenetic Karst Aquifer, Mammoth Cave, Ky, Chelsey Kipper

Masters Theses & Specialist Projects

An often overlooked connection between karst groundwater systems and surface water is spring flow reversal, the flow of river water into karst springs caused by changes in hydraulic gradient. Karst aquifers are subject to the intrusion of river water when the hydraulic head of a base level river is higher than the hydraulic head of a base level spring. When this occurs, the flow out of the spring reverses, allowing river water to enter base level conduits. River water thus becomes a source of recharge into karst basins, transporting both valuable nutrients and harmful contaminants into karst aquifers. The rapid …


Genesis Of Iron And Manganese Sediments In Zoloushka Cave (Ukraine/Moldova) As Revealed By Δ13C Organic Carbon, Piotr Kotula, Viacheslav Andreychouk, Jacek Pawlyta, Leszek Marynowski, Izabela Jendrzejewska Sep 2019

Genesis Of Iron And Manganese Sediments In Zoloushka Cave (Ukraine/Moldova) As Revealed By Δ13C Organic Carbon, Piotr Kotula, Viacheslav Andreychouk, Jacek Pawlyta, Leszek Marynowski, Izabela Jendrzejewska

International Journal of Speleology

Zoloushka Cave is one of the largest maze gypsum caves in the world. Mining of the gypsum bedrock and lowering of the water level due to the pumping of groundwater led to exposure of the cave passages to vadose conditions and changed the hydrochemistry of the karst water. As a result, large quantities of Fe and Mn hydroxides were deposited in the passages. It was found that at least two groups of various organisms were involved in depositing ferrous and manganese sediments. In order to establish the mechanism of deposition, we conducted chemical analyses of the sediments and isotopic analyses …


Oldowan Tool Behaviors Through Time On The Homa Peninsula, Kenya, Emma M. Finestone Sep 2019

Oldowan Tool Behaviors Through Time On The Homa Peninsula, Kenya, Emma M. Finestone

Dissertations, Theses, and Capstone Projects

The adaptive significance of tool use to genus Homo is a central theme in human origins. However, what we know from the early Oldowan sites suggests that persistent technology may have begun as an opportunistic behavior with minimal investment, rather than a habitual and widespread adaptive revolution. This dissertation seeks to investigate investment in Oldowan tool production on the Homa Peninsula, Kenya, considering raw material selection, transport, and lithic production at two newly discovered Oldowan localities: Nyayanga (ca. 2.6 Ma) and Sare River (ca. 1.7 Ma).

The first section of this dissertation outlines a method that enables the comparison of …


Environmental Assessment Of Arsenic And Mercury Levels At The Garfield Mill Site, Calico, California, Steven Gregory Thorp Sep 2019

Environmental Assessment Of Arsenic And Mercury Levels At The Garfield Mill Site, Calico, California, Steven Gregory Thorp

Electronic Theses, Projects, and Dissertations

Environmental impacts of mining at Calico, California, are poorly understood in comparison to the details of its history of silver production. Human health risks associated with arsenic from the lode rock, as well as mercury from the silver milling process, include central nervous system damage, organ failure, and death. To quantify the potential human health risk and manage remediation of this site, tailings from the Garfield Mill site were digitally mapped and chemically analyzed by portable x-ray fluorescence, which permitted volumetric estimates of total mill tailings and the arsenic and mercury budget, as well as identification of anomalies in the …