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Full-Text Articles in Geology

Geologic Map Of The Lima Peaks 7.5' Quadrangle, Beaverhead County, Montana, Betty Skipp, William J. Perry Jr., Susanne U. Jänecke Jan 2017

Geologic Map Of The Lima Peaks 7.5' Quadrangle, Beaverhead County, Montana, Betty Skipp, William J. Perry Jr., Susanne U. Jänecke

Geosciences Faculty Publications

The Lima Peaks quadrangle is located in southwestern Beaverhead County in southwestern-most Montana, near the southern terminus of the Beaverhead Mountains (fig. 1). Rocks and deposits of Mississippian through Quaternary age are present along the eastern margin of the Cretaceous to early Tertiary Sevier fold-and-thrust belt. This area is structurally complex because rocks of older, Laramide Blacktail-Snowcrest uplift (Perry and others, 1988; Skipp, 1988; Lonn and others, 2006).


Revised Structure And Correlation Of The Great Salt Lake, North Promontory, Rozel And Hansel Valley Fault Zones Revealed By The 2015-2016 Low Stand Of Great Salt Lake, Susanne U. Jänecke, James P. Evans Jan 2017

Revised Structure And Correlation Of The Great Salt Lake, North Promontory, Rozel And Hansel Valley Fault Zones Revealed By The 2015-2016 Low Stand Of Great Salt Lake, Susanne U. Jänecke, James P. Evans

Geosciences Faculty Publications

Years of drought conspired to produce the present historic low stand in Gunnison Bay of Great Salt Lake. The lake has receded enough to expose the Great Salt Lake fault zone, and reveal its geometry through the shallow and clear lake water. We mapped the newly visible escarpments along the fault zone, upgraded the Utah fault map, and revised the regional correlation of the Great Salt Lake, Rozel, and North Promontory fault zones. We explored the origin of wave-cut platforms in the footwall of the faults, and identify geometrically unique types of microbial communities along faults and fault-related springs and …


Preservation Of Sea Anemone Burrows In Silurian (~432 Million Years Old) Carbonate Rocks Of Southeastern Indiana, Usa, Marissa Tomin Jan 2017

Preservation Of Sea Anemone Burrows In Silurian (~432 Million Years Old) Carbonate Rocks Of Southeastern Indiana, Usa, Marissa Tomin

Williams Honors College, Honors Research Projects

Preservation of trace fossils (ichnofossils) in siliciclastic environments is often quite different from preservation in carbonate environments, representing an important source of variation that must be well understood in order to enhance interpretations of paleoenvironments and paleoecology. This study focuses on Conostichus, a relatively common burrow constructed by solitary sea anemones. These trace fossils are generally well-preserved (i.e., they display detailed external features) in siliciclastic rocks but are typically little more than conical masses in carbonate rocks. However, certain specimens recovered from the middle Silurian Massie Formation at the Napoleon quarry of southeastern Indiana are composed entirely out of …


Pressure Dependence Of Polycrystalline Magnesite And Dolomite, Cole Blasko Jan 2017

Pressure Dependence Of Polycrystalline Magnesite And Dolomite, Cole Blasko

Williams Honors College, Honors Research Projects

Intermediate depth (170-400 km) deep focus earthquakes are observed in subducting slabs, but unlike shallow (50-170 km) and deep (400-660 km) deep focus earthquakes, the mechanism(s) responsible for them are not clear. Two common alteration products observed in peridotites, magnesite and dolomite, are stable along the pressure-temperature path of a subducting slab. Low pressure experiments indicate that these minerals are weaker than olivine, but there are no data about the pressure dependence of the strength of magnesite or dolomite. Magnesite and dolomite cylinders (1mm by 1mm) were deformed in stacked series to 25-30% strain using the deformation-DIA (DDIA) at Argonne …


Glacial Deposits, Vol. 42, 2017, Department Of Geography, Geology, And The Environment Jan 2017

Glacial Deposits, Vol. 42, 2017, Department Of Geography, Geology, And The Environment

Glacial Deposits

Newsletter of the Department of Geography, Geology, and the Environment


Mercury Increases In Lake Tanganyika Since ~1850, Troy A. Bole Jan 2017

Mercury Increases In Lake Tanganyika Since ~1850, Troy A. Bole

Williams Honors College, Honors Research Projects

A series of three sediment cores were collected in Lake Tanganyika, Africa, and were analyzed for mercury concentrations. For all three cores, a decrease in mercury (Hg) levels was observed from the 1600’s (appx. 20 ng/g) until concentrations reached a minimum during the mid-1800’s (appx. 10 ng/g). The mid-1800’s marked a change from decreasing mercury levels to an increase over the following century. The core tops (circa 2006) have concentrations greater than 70 ng/g. The onset of the rise in mercury concentrations coincides with the beginning of the Industrial Revolution in the mid to late 18th century. Relationships between …


Carbon Cycle Trends Recorded By Organic Carbon Stable Isotopes In Paleocene Strata, Benton County, Mississippi: Implications For Chronostratigraphy Of The Porters Creek And Naheola Formations, Erica Gerweck Jan 2017

Carbon Cycle Trends Recorded By Organic Carbon Stable Isotopes In Paleocene Strata, Benton County, Mississippi: Implications For Chronostratigraphy Of The Porters Creek And Naheola Formations, Erica Gerweck

Electronic Theses and Dissertations

The paleocene-eocene thermal maximum (petm) is one of the most studied carbon isotope excursions in earth's history. The petm occurred 55 million years ago when excess isotopically heavy carbon (c13) was added into earth's carbon cycle, resulting in ecological and environmental changes. The petm is marked by a negative stable carbon isotope excursion (cie) in marine and continental strata around the globe. The paleocene and eocene boundary is contained in the sedimentary fill of the Mississippi embayment so there is high potential to produce new petm stable isotope datasets. The purpose of this project is to analyze the boundary for …


Great Plains Geology, Robert F. Diffendal Jr. Jan 2017

Great Plains Geology, Robert F. Diffendal Jr.

University of Nebraska Press: Sample Books and Chapters

Great Plains Geology concisely guides readers through the geological development of the Great Plains region. It describes the distinct features of fifty-seven geologic sites, including fascinating places such as Raton Pass in Colorado and New Mexico, the Missouri Breaks of Montana, and the Ashfall Fossil Beds in Nebraska. This guide addresses the tricky question of what constitutes the Great Plains, showing that the region is defined in part through its unique geologic features.


Developing A Gis Tool For Infinite Slope Stability Analysis (Gis-Tissa), Jonathon Sanders Jan 2017

Developing A Gis Tool For Infinite Slope Stability Analysis (Gis-Tissa), Jonathon Sanders

Dissertations, Master's Theses and Master's Reports

The Probabilistic Infinite Slope Analysis model (PISA-m) is a widely used computer program that uses infinite slope equations to calculate the spatially varying Factor of Safety of slopes. ESRI’s ArcGIS software and accompanying geoprocessing tools have become a mainstay in spatial data processing, and received full support for Python with the release of version 10. With many of the geoprocessing tools now available as a Python function, the software can be used for physics-based spatial landslide hazard analysis. A model that mimics PISA-m and its processing of normally distributed soil properties was created using the Python utility as a tool …


Drivers Of Sediment Accumulation And Nutrient Burial In Coastal South Carolina Residential Stormwater Detention Ponds, William Schroer Jan 2017

Drivers Of Sediment Accumulation And Nutrient Burial In Coastal South Carolina Residential Stormwater Detention Ponds, William Schroer

Theses and Dissertations

Stormwater detention ponds are widely utilized as control structures to manage runoff waters during storm events. These sediments also represent significant sites of organic carbon and nutrient burial. Here, carbon (C) and nutrient sources and burial rates were determined in 14 residential stormwater detention ponds throughout coastal counties of South Carolina. Bulk sediment accumulation was directly correlated with catchment impervious surface coverage (R2 = 0.90) with sediment accumulation rates ranging from 0.06 to 0.50 cm y-1. These rates of sediment accumulation and subsequent pond volume loss are lower than expected indicating that required maintenance dredging schedules be reassessed. Strong, positive …


High Resolution Gravity, Helicopter Magnetic, And Electromagnetic Study, Haile Gold Mine, South Carolina, Saad Saud Alarifi Jan 2017

High Resolution Gravity, Helicopter Magnetic, And Electromagnetic Study, Haile Gold Mine, South Carolina, Saad Saud Alarifi

Theses and Dissertations

The goal of this research was to calibrate and test geophysical methods for the detection of disseminated sulfides in the area of the Haile Gold Mine, South Carolina. The work focused on the calibration of high resolution gravity, and helicopter electromagnetic (EM) and magnetic data provided by OceanaGold. While high resolution potential field data (gravity and magnetics) has not been proven to be effective at small scales in exploration for disseminated sulfides, there is a strong regional correlation between high amplitude gravity and magnetic anomalies and the most productive gold mines in the Carolina terrane. Helicopter EM methods have been …


Quantifying Ephemeral Gully Erosion With Photogrammetry Surveying, C. B. Weerasekara, A. Y. Shechukov Jan 2017

Quantifying Ephemeral Gully Erosion With Photogrammetry Surveying, C. B. Weerasekara, A. Y. Shechukov

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Review Of A Chorus Of Cranes: The Cranes Of North America And The World By Paul A. Johnsgard, Aaron T. Pearse Jan 2017

Review Of A Chorus Of Cranes: The Cranes Of North America And The World By Paul A. Johnsgard, Aaron T. Pearse

United States Geological Survey: Staff Publications

Cranes (Gruidae) are widely distributed throughout the world, have lived on Earth for several million years, and currently reside on five continents. Archaeological evidence and historical references suggest that humans have interacted with and been captivated by cranes for many thousands of years (e.g., Leslie 1988, Muellner 1990). A glimpse of our reverence for these birds can be found in A Chorus of Cranes by Paul A. Johnsgard, with photographs by Thomas D. Mangelsen. Many species of cranes are currently identified as threatened or endangered, and their future will likely rest in the hands of humans; this book presents their …


Variation In Δ15N And Δ13C Values Of Forages For Arctic Caribou: Effects Of Location, Phenology And Simulated Digestion, Lindsay L. Vansomeren, Perry S. Barboza, David D. Gustine, M. Syndonia Bret-Harte Jan 2017

Variation In Δ15N And Δ13C Values Of Forages For Arctic Caribou: Effects Of Location, Phenology And Simulated Digestion, Lindsay L. Vansomeren, Perry S. Barboza, David D. Gustine, M. Syndonia Bret-Harte

United States Geological Survey: Staff Publications

RATIONALE: The use of stable isotopes for dietary estimates of wildlife assumes that there are consistent differences in isotopic ratios among diet items, and that the differences in these ratios between the diet item and the animal tissues (i.e., fractionation) are predictable. However, variation in isotopic ratios and fractionation of δ13C and δ15N values among locations, seasons, and forages are poorly described for arctic herbivores especially migratory species such as caribou (Rangifer tarandus).

METHODS: We measured the δ13Cand δ15N values of seven species of forage growing along a 200-km …


Assessment Of Frequency And Duration Of Point Counts When Surveying For Golden Eagle Presence, Ben R. Skipper, Clint W. Boal, Jo-Szu Tsai, Mark R. Fuller Jan 2017

Assessment Of Frequency And Duration Of Point Counts When Surveying For Golden Eagle Presence, Ben R. Skipper, Clint W. Boal, Jo-Szu Tsai, Mark R. Fuller

United States Geological Survey: Staff Publications

We assessed the utility of the recommended golden eagle (Aquila chrysaetos) survey methodology in the U.S. Fish and Wildlife Service 2013 Eagle Conservation Plan Guidance. We conducted 800-m radius, 1-hr point-count surveys broken into 20-min segments, during 2 sampling periods in 3 areas within the Intermountain West of the United States over 2 consecutive breeding seasons during 2012 and 2013. Our goal was to measure the influence of different survey time intervals and sampling periods on detectability and use estimates of golden eagles among different locations. Our results suggest that a less intensive effort (i.e., survey duration shorter …


Flood Effects Provide Evidence Of An Alternate Stable State From Dam Management On The Upper Missouri River, K. Skalak, A. Benthem, C. Hupp, E. Schenk, J. Galloway, R. Nustad Jan 2017

Flood Effects Provide Evidence Of An Alternate Stable State From Dam Management On The Upper Missouri River, K. Skalak, A. Benthem, C. Hupp, E. Schenk, J. Galloway, R. Nustad

United States Geological Survey: Staff Publications

We examine how historic flooding in 2011 affected the geomorphic adjustments created by dam regulation along the approximately 120 km free flowing reach of the Upper Missouri River bounded upstream by the Garrison Dam (1953) and downstream by Lake Oahe Reservoir (1959) near the City of Bismarck, ND, USA. The largest flood since dam regulation occurred in 2011. Flood releases from the Garrison Dam began in May 2011 and lasted until October, peaking with a flow of more than 4200m3 s-1. Channel cross-section data and aerial imagery before and after the flood were compared with historic rates …


Micronuclei And Other Erythrocyte Nuclear Abnormalities In Fishes From The Great Lakes Basin,Usa, Ryan P. Braham, Vicki S. Blazer, Cassidy H. Shaw, Patricia M. Mazik Jan 2017

Micronuclei And Other Erythrocyte Nuclear Abnormalities In Fishes From The Great Lakes Basin,Usa, Ryan P. Braham, Vicki S. Blazer, Cassidy H. Shaw, Patricia M. Mazik

United States Geological Survey: Staff Publications

Biological markers (biomarkers) sensitive to genotoxic and mutagenic contamination in fishes are widely used to identify exposure effects in aquatic environments. The micronucleus assay was incorporated into a suite of indicators to assess exposure to genotoxic and mutagenic contamination at five Great Lakes Areas of Concern (AOCs), as well as one non-AOC (reference) site. The assay allowed enumeration of micronuclei as well as other nuclear abnormalities for both site and species comparisons. Erythrocyte abnormality data was also compared to skin and liver tumor prevalence and hepatic transcript abundance. Erythrocyte abnormalities were observed at all sites with variable occurrence and severity …


Challenges For Creating A Site-Specific Groundwater-Use Record For The Ozark Plateaus Aquifer System (Central Usa) From 1900 To 2010, Katherine J. Knierim, Anna M. Nottmeier, Scott Worland, Drew A. Westerman, Brian R. Clark Jan 2017

Challenges For Creating A Site-Specific Groundwater-Use Record For The Ozark Plateaus Aquifer System (Central Usa) From 1900 To 2010, Katherine J. Knierim, Anna M. Nottmeier, Scott Worland, Drew A. Westerman, Brian R. Clark

United States Geological Survey: Staff Publications

Hydrologic budgets to determine groundwater availability are important tools for water-resource managers. One challenging component for developing hydrologic budgets is quantifying water use through time because historical and site-specific water-use data can be sparse or poorly documented. This research developed a groundwater-use record for the Ozark Plateaus aquifer system (central USA) from 1900 to 2010 that related county-level aggregated water-use data to site-specific well locations and aquifer units. A simple population-based linear model, constrained to 0 million liters per day in 1900, provided the best means to extrapolate groundwater-withdrawal rates pre-1950s when there was a paucity of water-use data. To …


Habitat Mosaics And Path Analysis Can Improve Biological Conservation Of Aquatic Biodiversity In Ecosystems With Low-Head Dams, Sean M. Hitchman, Martha E. Mather, Joseph M. Smith, Jane S. Fencl Jan 2017

Habitat Mosaics And Path Analysis Can Improve Biological Conservation Of Aquatic Biodiversity In Ecosystems With Low-Head Dams, Sean M. Hitchman, Martha E. Mather, Joseph M. Smith, Jane S. Fencl

United States Geological Survey: Staff Publications

Conserving native biodiversity depends on restoring functional habitats in the face of human-induced disturbances. Low-head dams are a ubiquitous human impact that degrades aquatic ecosystems worldwide. To improve our understanding of how low-head dams impact habitat and associated biodiversity, our research examined complex interactions among three spheres of the total environment. i.e., how low-head dams (anthroposphere) affect aquatic habitat (hydrosphere), and native biodiversity (biosphere) in streams and rivers. Creation of lake-like habitats upstream of low-head dams is a well-documented major impact of dams. Alterations downstream of low head dams also have important consequences, but …


Temporal Shift Of Sea Turtle Nest Sites In An Eroding Barrier Island Beach, Ikuko Fujisaki, Margaret Lamont, Ray Carthy Jan 2017

Temporal Shift Of Sea Turtle Nest Sites In An Eroding Barrier Island Beach, Ikuko Fujisaki, Margaret Lamont, Ray Carthy

United States Geological Survey: Staff Publications

Shoreline changes affect functionality of a sandy beach as a wildlife habitat and coastal erosion is among the primary causes of the changes. We examined temporal shifts in locations where loggerheads placed nests in relation to coastal erosion along a barrier island beach in the northern Gulf of Mexico. We first confirmed consistency in long-term (1855–2001), short-term (1976–2001), and more recent (2002–2012) shoreline change rates in two adjacent beach sections, one historically eroding (west beach) and the other accreting (east beach). The mean annual shoreline change rate in the two sections was significantly different in all time periods. The recent …


Degradation Of Crude 4‑Mchm (4-Methylcyclohexanemethanol) In Sediments From Elk River, West Virginia, Isabelle M. Cozzarelli, Denise M. Akob, Mary Jo Baedecker, Tracey Spencer, Jeanne Jaeschke, Darren S. Dunlap, Adam C. Mumford, Amisha T, Poret-Peterson, Douglas B. Chambers Jan 2017

Degradation Of Crude 4‑Mchm (4-Methylcyclohexanemethanol) In Sediments From Elk River, West Virginia, Isabelle M. Cozzarelli, Denise M. Akob, Mary Jo Baedecker, Tracey Spencer, Jeanne Jaeschke, Darren S. Dunlap, Adam C. Mumford, Amisha T, Poret-Peterson, Douglas B. Chambers

United States Geological Survey: Staff Publications

In January 2014, approximately 37 800 L of crude 4-methylcyclohexanemethanol (crude MCHM) spilled into the Elk River, West Virginia. To understand the long-term fate of 4-MCHM, we conducted experiments under environmentally relevant conditions to assess the potential for the 2 primary compounds in crude MCHM (1) to undergo biodegradation and (2) for sediments to serve as a long-term source of 4-MCHM. We developed a solid phase microextraction (SPME) method to quantify the cis- and transisomers of 4-MCHM. Autoclaved Elk River sediment slurries sorbed 17.5% of cis-4-MCHM and 31% of trans-4-MCHM from water during the 2-week experiment. …


Design Tradeoffs In Long-Term Research For Stream Salamanders, Adrianne B. Brand, Evan H. Campbell Grant Jan 2017

Design Tradeoffs In Long-Term Research For Stream Salamanders, Adrianne B. Brand, Evan H. Campbell Grant

United States Geological Survey: Staff Publications

Long-term research programs can benefit from early and periodic evaluation of their ability to meet stated objectives. In particular, consideration of the spatial allocation of effort is key. We sampled 4 species of stream salamanders intensively for 2 years (2010–2011) in the Chesapeake and Ohio Canal National Historical Park, Maryland, USA to evaluate alternative distributions of sampling locations within stream networks, and then evaluated via simulation the ability of multiple survey designs to detect declines in occupancy and to estimate dynamic parameters (colonization, extinction) over 5 years for 2 species. We expected that fine scale microhabitat variables (e.g., cobble, detritus) …


Floristic Quality Index And Forested Floristic Quality Index: Assessment Tools For Restoration Projects And Monitoring Sites In Coastal Louisiana, Kari F. Cretini, William B. Wood, Jenneke M. Visser, Ken W. Krauss, Leigh Anne Sharp, Gregory D. Steyer, Gary P. Shaffer, Sarai C. Piazza Jan 2017

Floristic Quality Index And Forested Floristic Quality Index: Assessment Tools For Restoration Projects And Monitoring Sites In Coastal Louisiana, Kari F. Cretini, William B. Wood, Jenneke M. Visser, Ken W. Krauss, Leigh Anne Sharp, Gregory D. Steyer, Gary P. Shaffer, Sarai C. Piazza

United States Geological Survey: Staff Publications

In 2003, the Coastwide Reference Monitoring System (CRMS) program was established in coastal Louisiana marshes and swamps to assess the effectiveness of individual coastal restoration projects and the cumulative effects of multiple projects at regional and coastwide scales (Steyer et al., 2003). In order to make these assessments, analytical teams were assembled for each of the primary data types sampled under theCRMS program, including vegetation, hydrology, landscape, and soils. These teams consisted of scientists and support staff from the US Geological Survey and other federal agencies, the Coastal Protection and Restoration Authority of Louisiana, and university academics. Each team was …


Linking Animals Aloft With The Terrestrial Landscape, Jeffrey J. Buler, Wylie C. Barrow Jr., Matthew E. Boone, Deanna K. Dawson, Robert H. Diehl, Frank R. Moore, Lori A. Randall, Timothy D. Schreckengost, Jaclyn A. Smolinsky Jan 2017

Linking Animals Aloft With The Terrestrial Landscape, Jeffrey J. Buler, Wylie C. Barrow Jr., Matthew E. Boone, Deanna K. Dawson, Robert H. Diehl, Frank R. Moore, Lori A. Randall, Timothy D. Schreckengost, Jaclyn A. Smolinsky

United States Geological Survey: Staff Publications

Despite using the aerosphere for many facets of their life, most flying animals (i.e., birds, bats, some insects) are still bound to terrestrial habitats for resting, feeding, and reproduction. Comprehensive broad-scale observations by weather surveillance radars of animals as they leave terrestrial habitats for migration or feeding flights can be used to map their terrestrial distributions either as point locations (e.g., communal roosts) or as continuous surface layers (e.g., animal densities in habitats across a landscape). We discuss some of the technical challenges to reducing measurement biases related to how radars sample the aerosphere and the flight behavior of animals. …


Extending The Habitat Concept To The Airspace, Robert H. Diehl, Anna C. Peterson, Rachel T. Bolus, Douglas Johnson Jan 2017

Extending The Habitat Concept To The Airspace, Robert H. Diehl, Anna C. Peterson, Rachel T. Bolus, Douglas Johnson

United States Geological Survey: Staff Publications

Habitat is one of the most familiar and fundamental concepts in the fields of ecology, animal behavior, and wildlife conservation and management. Humans interact with habitats through their senses and experiences and education to such a degree that their perceptions of habitat have become second nature. For this reason, it may be difficult at first to accept the airspace as habitat, an area that is invisible, untouchable, highly dynamic, and its occupants difficult to see. Nonetheless, the habitat concept, by definition and in practice, applies readily to the airspace. Some ecological and behavioral processes including habitat selection, foraging, and reproduction …


Linking Animals Aloft With The Terrestrial Landscape, Jeffrey J. Buler, Wylie C. Barrow Jr., Matthew E. Boone, Deanna K. Dawson, Robert H. Diehl, Frank R. Moore, Lori A. Randall, Timothy D. Schreckengost, Jaclyn A. Smolinsky Jan 2017

Linking Animals Aloft With The Terrestrial Landscape, Jeffrey J. Buler, Wylie C. Barrow Jr., Matthew E. Boone, Deanna K. Dawson, Robert H. Diehl, Frank R. Moore, Lori A. Randall, Timothy D. Schreckengost, Jaclyn A. Smolinsky

United States Geological Survey: Staff Publications

Despite using the aerosphere for many facets of their life, most flying animals (i.e., birds, bats, some insects) are still bound to terrestrial habitats for resting, feeding, and reproduction. Comprehensive broad-scale observations by weather surveillance radars of animals as they leave terrestrial habitats for migration or feeding flights can be used to map their terrestrial distributions either as point locations (e.g., communal roosts) or as continuous surface layers (e.g., animal densities in habitats across a landscape). We discuss some of the technical challenges to reducing measurement biases related to how radars sample the aerosphere and the flight behavior of animals. …


Extending The Habitat Concept To The Airspace, Robert H. Diehl, Anna C. Peterson, Rachel T. Bolus, Douglas Johnson Jan 2017

Extending The Habitat Concept To The Airspace, Robert H. Diehl, Anna C. Peterson, Rachel T. Bolus, Douglas Johnson

United States Geological Survey: Staff Publications

Habitat is one of the most familiar and fundamental concepts in the fields of ecology, animal behavior, and wildlife conservation and management. Humans interact with habitats through their senses and experiences and education to such a degree that their perceptions of habitat have become second nature. For this reason, it may be difficult at first to accept the airspace as habitat, an area that is invisible, untouchable, highly dynamic, and its occupants difficult to see. Nonetheless, the habitat concept, by definition and in practice, applies readily to the airspace. Some ecological and behavioral processes including habitat selection, foraging, and reproduction …


Water-Level And Recoverable Water In Storage Changes, High Plains Aquifer, Predevelopment To 2015 And 2013–15, Virginia L. Mcguire Jan 2017

Water-Level And Recoverable Water In Storage Changes, High Plains Aquifer, Predevelopment To 2015 And 2013–15, Virginia L. Mcguire

United States Geological Survey: Staff Publications

The High Plains aquifer underlies 111.8 million acres (about 175,000 square miles) in parts of eight States—Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Water-level declines began in parts of the High Plains aquifer soon after the beginning of substantial irrigation with groundwater in the aquifer area (about 1950). This report presents water-level changes and change in recoverable water in storage in the High Plains aquifer from predevelopment (about 1950) to 2015 and from 2013 to 2015.

The methods to calculate area-weighted, average water-level changes; change in recoverable water in storage; and total recoverable water in storage …


Key Differences Between Lakes And Reservoirs Modify Climate Signals: A Case For A New Conceptual Model, Nicole M. Hayes, Bridget R. Deemer, Jessica R. Corman, N. Roxanna Razavi, Kristin E. Strock Jan 2017

Key Differences Between Lakes And Reservoirs Modify Climate Signals: A Case For A New Conceptual Model, Nicole M. Hayes, Bridget R. Deemer, Jessica R. Corman, N. Roxanna Razavi, Kristin E. Strock

United States Geological Survey: Staff Publications

Lakes and reservoirs are recognized as important sentinels of climate change, integrating catchment and atmospheric climate change drivers. Climate change conceptual models generally consider lakes and reservoirs together despite the possibility that these systems respond differently to climate-related drivers. Here, we synthesize differences between lake and reservoir characteristics that are likely important for predicting waterbody response to climate change. To better articulate these differences, we revised the energy mass flux framework, a conceptual model for the effects of climate change on lentic ecosystems, to explicitly consider the differential responses of lake versus reservoir ecosystems. The model predicts that catchment and …


Analysis Of Volcanic Ash, Conor O'Dowd Jan 2017

Analysis Of Volcanic Ash, Conor O'Dowd

Senior Honors Theses and Projects

Volcanic ash begins to weather upon deposition, resulting in the in situ development of clay minerals in the glass pore spaces. Almquist (2011) established a classification scheme of weathering based on ash deposits in New Zealand using an SEM. We are examining volcanic ash collected from Mount St. Helens, New Zealand, and Cobble Cuesta of the Gabbs Valley Basin to broaden the classification scheme based on morphology and authigenic clay mineral composition. SEM and XRD analysis of the material were used to get a better understanding of the morphology and geochemistry of the weathering products. By broadening the weathering classification …