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2019

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Articles 721 - 750 of 1657

Full-Text Articles in Earth Sciences

A New Plumbing System Framework For Mantle Plume-Related Continental Large Igneous Provinces And Their Mafic-Ultramafic Intrusions, Richard E. Ernst, Dustin A. Liikane, Simon M. Jowitt, K. L. Buchan, J. A. Blanchard Jul 2019

A New Plumbing System Framework For Mantle Plume-Related Continental Large Igneous Provinces And Their Mafic-Ultramafic Intrusions, Richard E. Ernst, Dustin A. Liikane, Simon M. Jowitt, K. L. Buchan, J. A. Blanchard

Geoscience Faculty Research

The magmatic components of continental Large Igneous Provinces (LIPs) include flood basalts and their plumbing system of giant mafic dyke swarms (radiating, linear, and the recently discovered circumferential type), mafic sill provinces, a lower crustal magmatic underplate, mafic-ultramafic (M–UM) intrusions, associated silicic magmatism, and associated carbonatites and kimberlites. This paper proposes a new plumbing system framework for mantle plume-related continental LIPs that incorporates all of these components, and provides a context for addressing key thematic aspects such as tracking magma batches “upstream” and “downstream” and their geochemical evolution, assessing the setting of M-UM intrusions and their economic potential, interpreting deep …


Regional Modeling Of The Glaciers Of The North Cascades Mountains, Washington, Usa, Christina Eileen Gray Jul 2019

Regional Modeling Of The Glaciers Of The North Cascades Mountains, Washington, Usa, Christina Eileen Gray

Dissertations and Theses

Glaciers in the North Cascades store winter snowfall as ice and release it in late summer as melt, providing an important regional source of water and hydroelectric energy. The future of glaciers in the North Cascades, Washington, were evaluated using a regional glaciation model driven by the Community Climate System Model 4 global climate model. The climate model was coupled with three Representative Concentration Pathways (RCPs), 2.6, 4.5, and 8.5. These RCPs provide a business-as-usual scenario (RCP 8.5), which assumes society makes little to no efforts to reduce greenhouse gas emissions, a best-case scenario (RCP 2.6) with strong attempts to …


Early Mississippian Ocean Anoxia Triggering Organic Carbon Burial And Enhancing Late Paleozoic Ice Age Onset: Evidence From Uranium Isotopes Of Marine Limestones, Keyi Cheng Jul 2019

Early Mississippian Ocean Anoxia Triggering Organic Carbon Burial And Enhancing Late Paleozoic Ice Age Onset: Evidence From Uranium Isotopes Of Marine Limestones, Keyi Cheng

Earth and Planetary Sciences ETDs

The Early Mississippian (Tournaisian) positive δ13C excursion (or TICE) is one of the largest recorded in the Phanerozoic and the organic carbon (OC) burial associated with its development is hypothesized to have driven global cooling and increased glaciation. We are testing the hypothesis that expanded ocean euxinia/anoxia drove widespread OC burial and the TICE and we are testing this hypothesis using uranium isotopes (δ238U) of Lower Mississippian marine limestones from southern Nevada as a global seawater redox proxy.

δ238U trends record a prominent mid-Tournaisian negative excursion (~0.30‰ magnitude) lasting ~1 My. The lack of …


Collaborative Research: Tespresso, Tectonic Encoding, Shredding, And Propagation Of Environmental Signals As Surficial Observables, Tammy M. Rittenour Jul 2019

Collaborative Research: Tespresso, Tectonic Encoding, Shredding, And Propagation Of Environmental Signals As Surficial Observables, Tammy M. Rittenour

Funded Research Records

No abstract provided.


A Vacancy-Rich, Partially Inverted Spinelloid Silicate, (Mg,Fe,Si)(2)(Si,)O-4, As A Major Matrix Phase In Shock Melt Veins Of The Tenham And Suizhou L6 Chondrites, Oliver Tschauner, Chi Ma, Luca Bindi, John R. Beckett, Xiande Xie Jul 2019

A Vacancy-Rich, Partially Inverted Spinelloid Silicate, (Mg,Fe,Si)(2)(Si,)O-4, As A Major Matrix Phase In Shock Melt Veins Of The Tenham And Suizhou L6 Chondrites, Oliver Tschauner, Chi Ma, Luca Bindi, John R. Beckett, Xiande Xie

Geoscience Faculty Research

A new high‐pressure silicate, (Mg,Fe,Si)2(Si,□)O4 with a tetragonal spinelloid structure, was discovered within shock melt veins in the Tenham and Suizhou meteorites, two highly shocked L6 ordinary chondrites. Relative to ringwoodite, this phase exhibits an inversion of Si coupled with intrinsic vacancies and a consequent reduction of symmetry. Most notably, the spinelloid makes up about 30–40 vol% of the matrix of shock veins with the remainder composed of a vitrified (Mg,Fe)SiO3 phase (in Tenham) or (Mg,Fe)SiO3‐rich clinopyroxene (in Suizhou); these phase assemblages constitute the bulk of the matrix in the shock veins. Previous assessments of the melt matrices concluded that …


Evaluating Fluid Fluxes From Deep-Sea Seepage Habitats, Leigha E. Peterson Jul 2019

Evaluating Fluid Fluxes From Deep-Sea Seepage Habitats, Leigha E. Peterson

Electronic Theses and Dissertations

The permanently dark deep-sea, located at oceanic water depths greater than 200 m, represents the largest potential habitat space on Earth. The physicochemical conditions of the planet’s largest biome are tightly coupled to the exchange of matter and energy from terrestrial and sea-floor end-members. In fact, global ocean and climate systems are significantly impacted by deep-sea processes. Seafloor vents and seeps appear to act as geologic exchange conduits, returning recycled materials to the hydrosphere to sustain another generation of life. Despite submarine seepage having control on global elemental cycling, it is estimated that less than 1% of the deep-sea has …


Breakdown Mechanisms In Iron Caves. An Example From Brazil, Marcelo R. Barbosa, Allan D.F. Da Silva, Rafael G. De Paula, Georgete M. Dutra, Airton Barata, Iuri V. Brandi, Chrystophe R.P. Da Silva, Robert A. Osborne Jul 2019

Breakdown Mechanisms In Iron Caves. An Example From Brazil, Marcelo R. Barbosa, Allan D.F. Da Silva, Rafael G. De Paula, Georgete M. Dutra, Airton Barata, Iuri V. Brandi, Chrystophe R.P. Da Silva, Robert A. Osborne

International Journal of Speleology

An iron cave in the vicinity of a mine in Carajás, Brazil, was selected to be mined within an assisted elimination project, planned to control all mine advancement operations towards the cave along with a strict speleological physical monitoring. It allowed, in a pioneering way, the recording of events in the cave from the first signs of damage until to the total collapse of the cave. The project lasted four years and it was possible to identify and describe four breakdown mechanisms in iron caves: Fragment downfall, Block downfall, Controlling structure reactivation, and Open discontinuity movement. The mechanisms occurred independently …


La Evolucion De Glaciares De Escombros Y Morenas En La Cuenca Del Rio Blanco, Mendoza, William J. Wayne Jul 2019

La Evolucion De Glaciares De Escombros Y Morenas En La Cuenca Del Rio Blanco, Mendoza, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

RESUMEN: La subcuenca del río Blanco en el cordón del Plata, que incluye los valles de Angostura y Vallecitos, tiene 85 km2, de los cuales 4.7 km2 son de glaciares de escombros activos, 7.4 km" de glaciares de escombros fósiles y morrenas. Los dos valles con rumbo al sureste son erosionados en rocas volcánicas y contienen largas lenguas de glaciares de escombros que se extienden hasta los 3.300 m. Los dos valles con rumbo al este tuvieron glaciares hasta tiempos recientes y en uno de ellos aún existe un glaciar cubierto. Los glaciares de escombros en …


An Estimation Of Lower Tropospheric Mixing Derived From Inverse Modeling Of Boundary Layer Water Vapor Isotopologues On Graciosa Island, Azores, Jacquelyn M. Delp Jul 2019

An Estimation Of Lower Tropospheric Mixing Derived From Inverse Modeling Of Boundary Layer Water Vapor Isotopologues On Graciosa Island, Azores, Jacquelyn M. Delp

Earth and Planetary Sciences ETDs

Recent studies have shown water vapor isotopologues to be sensitive tracers of mixing processes that govern low-cloud feedback in climate models. In this study, we develop an inverse model (MBL Mix inverse model) that uses one year of isotope and humidity observations from Graciosa Island, Azores to estimate mixing for four seasons. We show the dry end-member of the model, the lower free troposphere (LFT), can be represented using Rayleigh fractionation. Isotope observations from Graciosa Island are compared to other field locations to discuss controls on isotopic variability other than mixing. Output from the MBL Mix inverse model shows the …


Estimating Live Fuel Moisture Using Smap L-Band Radiometer Soil Moisture For Southern California, Usa, Shenyue Jia, Seung Hee Kim, Son V. Nghiem, Menas Kafatos Jul 2019

Estimating Live Fuel Moisture Using Smap L-Band Radiometer Soil Moisture For Southern California, Usa, Shenyue Jia, Seung Hee Kim, Son V. Nghiem, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Live fuel moisture (LFM) is a field-measured indicator of vegetation water content and a crucial observation of vegetation flammability. This study presents a new multi-variant regression model to estimate LFM in the Mediterranean ecosystem of Southern California, USA, using the Soil Moisture Active Passive (SMAP) L-band radiometer soil moisture (SMAP SM) from April 2015 to December 2018 over 12 chamise (Adenostoma fasciculatum) LFM sites. The two-month lag between SMAP SM and LFM was utilized either as steps to synchronize the SMAP SM to the LFM series or as the leading time window to calculate the accumulative SMAP SM. …


Stable Isotope Geochemistry Of Shelled Marine Invertebrates: Wide-Ranging Applications, Nasser M. Al-Qattan Jul 2019

Stable Isotope Geochemistry Of Shelled Marine Invertebrates: Wide-Ranging Applications, Nasser M. Al-Qattan

USF Tampa Graduate Theses and Dissertations

Mollusks grow by adding discrete growth layers throughout their lifetime (i.e., accretion). More specifically, most marine mollusks precipitate their shells in oxygen isotopic equilibrium with seawater or with a constant offset from equilibrium. The stable oxygen isotope values (δ18O) of their shells are determined by the temperature and δ18O values of the surrounding water during calcification without significant vital effects. In comparison, the stable carbon isotope values (δ13C) of their shells reflect those of the dissolved inorganic carbon (δ13C- DIC) and respired carbon dioxide. Therefore, variations in the oxygen and carbon isotope …


Gage County Preliminary Ground Water Study (Gm-20): Reed, E.C. Conservation And Survey Division , Size 8.5" X 11"., E.C. Reed Jul 2019

Gage County Preliminary Ground Water Study (Gm-20): Reed, E.C. Conservation And Survey Division , Size 8.5" X 11"., E.C. Reed

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Framing Geologic Numeracy For The Purpose Of Geoscience Education: The Geoscience Quantitative Preparation Survey, Victor J. Ricchezza Jul 2019

Framing Geologic Numeracy For The Purpose Of Geoscience Education: The Geoscience Quantitative Preparation Survey, Victor J. Ricchezza

USF Tampa Graduate Theses and Dissertations

The Geoscience Quantitative Preparation Survey (GQPS) was developed to address a deficiency in the available literature regarding the competency and preparation of early-career geologists in geoscience job-related quantitative skills – namely, geologic numeracy. The final version of the GQPS included self-confidence, usage, satisfaction, and demographic sections. The GQPS was expected to produce data that would allow for an evaluation of the geologic numeracy of early-career geologists and the success of approximately 20 years of increased focus on quantitatively literate geoscience graduates.

The self-confidence section of the GQPS included quantitative methods and quantitative skills. The usage section asked whether participants used …


Twenty-Three Unsolved Problems In Hydrology (Uph) -- A Community Perspective, Günter Blöschl, Marc F.P. Bierkens, Antonio Chambel, Christophe Cudennec, Georgia Destouni, Aldo Fiori, James W. Kirchner, Jeffrey J. Mcdonnell, Hubert H.G. Savenjie, Murugesu Sivapalan, Christine Stumpp, Elena Toth, Elena Volpi, Gemma Carr, Claire Lupton, Jose Salinas, Borbala Szeles, Alberto Viglione, Hafzullah Aksoy, Scott T. Allen, Anam Amin, Vazken Andreassian, Berit Arheimer, Santosh K. Aryal, Victor Baker, Earl Bardsley, Marlies H. Barendrecht, Alena Bartosova, Okke Batelaan, Wouter R. Berghuijs, Keith Beven Jul 2019

Twenty-Three Unsolved Problems In Hydrology (Uph) -- A Community Perspective, Günter Blöschl, Marc F.P. Bierkens, Antonio Chambel, Christophe Cudennec, Georgia Destouni, Aldo Fiori, James W. Kirchner, Jeffrey J. Mcdonnell, Hubert H.G. Savenjie, Murugesu Sivapalan, Christine Stumpp, Elena Toth, Elena Volpi, Gemma Carr, Claire Lupton, Jose Salinas, Borbala Szeles, Alberto Viglione, Hafzullah Aksoy, Scott T. Allen, Anam Amin, Vazken Andreassian, Berit Arheimer, Santosh K. Aryal, Victor Baker, Earl Bardsley, Marlies H. Barendrecht, Alena Bartosova, Okke Batelaan, Wouter R. Berghuijs, Keith Beven

Geoscience Faculty Research

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused …


Modeling And Assessing Lava Flow Hazards, Elisabeth Gallant Jul 2019

Modeling And Assessing Lava Flow Hazards, Elisabeth Gallant

USF Tampa Graduate Theses and Dissertations

Lava flow hazards are one of the few constant themes across the wide spectrum of volcanic research in the solar system. These dynamic hazards are controlled by the location of the eruption, the topography and material properties of the land upon which the flow spreads, and the properties of the lava (e.g., volume, temperature, and rheology). Understanding the influences on eruption location and how lava flows modify the landscape are important steps to accurately forecast volcanic hazards. Three studies are presented in this dissertation that address di˙erent aspects of modeling and assessing vent opening and lava flow hazards.

The first …


Sources And Chemical Stability Of Soil Organic Carbon Along A Salinity Gradient And A Chronosequence Of Created Brackish Marshes In Coastal Louisiana, Megan L. Kelsall Jul 2019

Sources And Chemical Stability Of Soil Organic Carbon Along A Salinity Gradient And A Chronosequence Of Created Brackish Marshes In Coastal Louisiana, Megan L. Kelsall

LSU Master's Theses

Tidal marshes have been recognized for providing a number of important ecological services including soil carbon sequestration. However, the loss of tidal marsh habitat due to climate change and anthropogenic stressors exposes previously stored soil organic carbon (SOC) to oxidation. The vulnerability of SOC to oxidation depends on its chemical stability and environmental conditions limiting decomposition. Labile organic carbon (LC), decomposes quickly unless abiotic conditions limit decomposition. Recalcitrant organic carbon (RC) decomposes slower and is stored for longer time periods. Predicting long-term storage of SOC is complicated by the potential for multiple SOC sources, differences in chemical stability, and variation …


Crop And Climate Suitability For Irrigated Agriculture In The Midlands Area Of Western Australia, 2nd Edition, Leon Van Wyk Jul 2019

Crop And Climate Suitability For Irrigated Agriculture In The Midlands Area Of Western Australia, 2nd Edition, Leon Van Wyk

Resource management technical reports

The Midlands groundwater and land assessment is a $4.7 million Water for Food project. Its aim is to confirm groundwater availability at one or more focus areas that may form precincts of 2000–3000 hectares suitable for intensive irrigated horticulture. This report forms part of this project.

Firstly, this report describes the climate of the Midlands study area and highlights the subtle differences between the two selected focus areas, Irwin and Dinner Hill. It discusses the importance of climate in determining crop suitability. We also investigated the following additional factors that determine crop suitability: water quality, water quantity, land capability (soils) …


Comparing Aerial Lidar Observations With Terrestrial Lidar And Snow-Probe Transects From Nasa's 2017 Snowex Campaign, Zach Uhlmann, Lucas Spaete, Nancy F. Glenn Jul 2019

Comparing Aerial Lidar Observations With Terrestrial Lidar And Snow-Probe Transects From Nasa's 2017 Snowex Campaign, Zach Uhlmann, Lucas Spaete, Nancy F. Glenn

Geosciences Faculty Publications and Presentations

NASA's 2017 SnowEx field campaign at Grand Mesa, CO, generated Airborne Laser Scans (ALS), Terrestrial Laser Scans (TLS), and snow‐probe transects, which allowed for a comparison between snow depth measurement techniques. At six locations, comparisons between gridded ALS and TLS observations, at 1‐m resolution, had a median snow depth difference of 5 cm, root‐mean‐square difference of 16 cm, mean‐absolute difference of 10 cm, and 3‐cm difference in standard deviation. ALS generally had greater but similar snow depth values to TLS, and results were not sensitive to the gridded cell size between 0.5 and 5 m. The greatest disagreements were where …


A Tourism Impact Index For Water-Based Natural Attractions Field-Tested In Subarctic And Maritime Climates, Jason Fox Jul 2019

A Tourism Impact Index For Water-Based Natural Attractions Field-Tested In Subarctic And Maritime Climates, Jason Fox

Masters Theses & Specialist Projects

Tourism in cold and cool-climate regions is largely characterized by recreational and sightseeing activities at water-based natural attractions such as beaches, coastal cliffs, and waterfalls. While the economic benefits of the tourism industry can contribute to a sustainable future for these regions, the environmental implications of a hastilydeveloped industry cannot be ignored given that cold-climate and cool-climate landscapes are at risk of rapid environmental change from a warming climate and other environmental concerns. This study consisted of the development of the Tourism Impact Index for Water-Based Natural Sites, the first of its kind, and its application and refinement in the …


Lithological Character And Sequence Stratigraphy Of The Ste. Genevieve Limestone In Western Kentucky, Zachary Dalton Creech Jul 2019

Lithological Character And Sequence Stratigraphy Of The Ste. Genevieve Limestone In Western Kentucky, Zachary Dalton Creech

Masters Theses & Specialist Projects

The Ste. Genevieve Limestone is a Mississippian-aged, carbonate-dominated stratigraphic unit that is a prominent hydrocarbon producer in the Illinois Basin, and is widely distributed in states such as Missouri, Kentucky, Indiana, and Illinois. There has been relatively limited study focused on characterizing the Ste. Genevieve Limestone in terms of lithofacies, stacking patterns, and sequence stratigraphic context via analysis of roadcut exposures of the unit in western Kentucky.

The focus of this study is to use lithologic data collected from roadcuts and draft these data into cross sections for presentation of detailed stratigraphic columns that are locally correlative. Seven roadcuts were …


The Effectiveness Of Mobile Eye-Tracking To Enhance Guided Show Cave Experiences, Jenna Michele Hammond Jul 2019

The Effectiveness Of Mobile Eye-Tracking To Enhance Guided Show Cave Experiences, Jenna Michele Hammond

Masters Theses & Specialist Projects

Karst terrains are landscapes with a distinctive hydrology and set of landforms that arise from a combination of high bedrock solubility and well-developed secondary (fracture) porosity. Karst areas are easily polluted due to the rapid transport of unfiltered percolating water through the systems. While many individuals are able to identify karst landforms such as sinkholes and caves, an understanding of the interconnectedness of the surface and subsurface in karst landscapes, as well as the vulnerability of karst areas to degradation, is often limited. Show caves, which are caves made accessible to visitation by humans through built infrastructure, can serve as …


An Urban Karst Aquifer Resource Evaluation And Monitoring Toolbox, Rachel Anne Kaiser Jul 2019

An Urban Karst Aquifer Resource Evaluation And Monitoring Toolbox, Rachel Anne Kaiser

Masters Theses & Specialist Projects

In urban karst areas, such as the City of Bowling Green, Kentucky and the Tampa Bay Metropolitan Area, groundwater quality faces a variety of threats. The development of residential, commercial, and industrial landuse types allows for a wide variety of groundwater pollutants to enter the karst groundwater systems. Various different models and indices have attempted evaluative approaches to identify issues in urban karst areas, but the methods vary by location and lack a focus on urban karst groundwater quality. There also exists a lack of a data-driven approach that is able to capture short- and long-term changes in threats to …


Sediment Monitoring To Support Modeling A Reservoir Sediment Flush On A Sand-Bed River In Northern Nebraska, Nathaniel J. Schaepe, Paul M. Boyd Jul 2019

Sediment Monitoring To Support Modeling A Reservoir Sediment Flush On A Sand-Bed River In Northern Nebraska, Nathaniel J. Schaepe, Paul M. Boyd

United States Geological Survey: Water Reports and Publications

The United States Geological Survey (USGS) in cooperation with the United States Army Corps of Engineers (USACE), monitored a sediment flush event from Spencer Dam located on the Niobrara River near Spencer, Nebraska, during the fall of 2014. Data collected during the flush was used to validate a one-dimensional sediment transport model developed by the USACE. The USACE surveyed 26 cross sections within the reservoir and as far as 1 kilometer (km) upstream from the reservoir pool to about 10 km downstream from the dam before and after the flushing event to measure erosion and deposition. They also collected surficial …


The Prairie Post Quarterly Newsletter Of The High Plains Regional Climate Center- July 2019, Natalie Umphlett, Rezaul Mamood, Paul Flanagan, Emily Brown, Gannon Rush, Crystal J. Stiles Jul 2019

The Prairie Post Quarterly Newsletter Of The High Plains Regional Climate Center- July 2019, Natalie Umphlett, Rezaul Mamood, Paul Flanagan, Emily Brown, Gannon Rush, Crystal J. Stiles

Prairie Post: Quarterly Newsletter of the High Plains Regional Climate Center

Inside this issue:

Message from the director........................................1

Staff spotlight...........................1

Spirit Lake workshop..............2

Product highlight....................3

Outreach events......................3

Research highlight..................4

Update on regional climate conditions..................................4

Northern Plains drought assessment................................5

Recent and upcoming travel and activities.............................6


Droughtscape, Fall 2019, Cory Matteson Jul 2019

Droughtscape, Fall 2019, Cory Matteson

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

From the Director

Quarterly drought summary

Quarterly drought impacts

Ranchers delayed response to drought

Drought Monitor celebrates 20 years

Drought Monitor state impact tables

Directorcontributesto U.N.droughtproject

Updated Drought Risk Atlas

New fact sheet lists recovery resources


Impacts Of Glacial Meltwater On Geochemistry And Discharge Of Alpine Proglacial Streams In The Wind River Range, Wyoming, Usa, Natalie Shepherd Barkdull Jul 2019

Impacts Of Glacial Meltwater On Geochemistry And Discharge Of Alpine Proglacial Streams In The Wind River Range, Wyoming, Usa, Natalie Shepherd Barkdull

Theses and Dissertations

Shrinking alpine glaciers alter the geochemistry of sensitive mountain streams by exposing reactive freshly-weathered bedrock and releasing decades of atmospherically-deposited trace elements from glacier ice. Changes in the timing and quantity of glacial melt also affect discharge and temperature of alpine streams. To investigate the effects of glacier ice melt on the geochemistry and hydrology of proglacial streams in the arid Intermountain West, we sampled supraglacial meltwaters and proglacial streams in the Dinwoody Creek watershed in the Wind River Range, Wyoming during late summer 2015, when the contributions of glacier meltwater were highest. Supraglacial meltwater was enriched in 8 trace …


Nature And Origin Of Fissure Ore At The Porphyry-Epithermal Transition Zone Of The Bingham Canyon Porphyry Cu-Au-Mo Deposit, Utah, David Harris Tomlinson Jul 2019

Nature And Origin Of Fissure Ore At The Porphyry-Epithermal Transition Zone Of The Bingham Canyon Porphyry Cu-Au-Mo Deposit, Utah, David Harris Tomlinson

Theses and Dissertations

Late-stage fissure-filling ore at the world class Bingham Canyon, Utah, porphyry copper deposit has long been recognized, but poorly studied. Physical and chemical characterization of the Pb-Zn-Cu-Ag-Au mineralized fissures in the porphyry-epithermal transition zone provides insight into the origin, timing, and controls of ore deposition. These sheared sulfide-rich fissures are dominated by pyrite and multiple generations of quartz, with lesser amounts of other sulfides and gangue minerals. Au (0.27 to 4.61 ppm) provides the most value to the ore in the transition zone. Host rocks include Eocene monzonite and Paleozoic limestone and quartzite"”all of which can contain economic ore bodies. …


Limitations To Photosynthesis In Silver Bow And Blacktail Creeks, Isaiah Robertson Jul 2019

Limitations To Photosynthesis In Silver Bow And Blacktail Creeks, Isaiah Robertson

Graduate Theses & Non-Theses

Throughout Silver Bow Creek’s history, consideration of the photosynthetic communities that make heterotrophic life possible have often been overlooked since macroinvertebrates made up a majority of ecosystem health assessments. Silver Bow Creek has had minimal biological research outside of macroinvertebrate surveys, especially as it pertains to photosynthetic organisms. This study assessed the photosynthetic communities of Silver Bow Creek and their limitations by limiting available light and comparing uptake of nutrients during a 23-day incubation experiment conducted at four sites along the flow of Silver Bow Creek and Blacktail Creek. At each site, nine one-liter microcosms, filled with creek water and …


Droughtscape, Summer 2019, Cory Matteson Jul 2019

Droughtscape, Summer 2019, Cory Matteson

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

From the Director

Quarterly drought summary

Quarterly drought impacts

NDMC welcomes African visitors

Ready for Drought game debuts

U.S. Virgin Islands added to USDM

Australian programmer visits NDMC

Upcoming events

Partnerships with NDMC extended


Glacial-Interglacial Changes In The Thermocline Structure Of The Makassar Strait: Implications For Changes In The Indonesian Throughflow, Michael Lis Jul 2019

Glacial-Interglacial Changes In The Thermocline Structure Of The Makassar Strait: Implications For Changes In The Indonesian Throughflow, Michael Lis

Theses and Dissertations

The Indo-Pacific Warm Pool exerts a strong influence on the global climate system because it partially controls heat and moisture exchange (pressure gradient) between the atmosphere and ocean, and thus, the intensity of the Indonesian throughflow (ITF) via the Makassar Strait, the main passage of water connecting the Pacific and Indian Oceans. The magnitude of ITF is reflected by the structure of the oceanic thermocline. Here, we use shell δ18O signatures and trace element composition of foraminifera (Globigerinoides ruber, Pulleniatina obliquiloculata, and Globigerinoides menardii) in two sediment records spanning the past 30 kya collected from …