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Two Modes Of Accelerated Glacier Sliding Related To Water, Joel T. Harper, Neil Humphrey, W. T. Pfeffer, Brian Lazar

Geosciences Faculty Publications

We present the first glacier-wide detailed measurement of basal effective pressure and related observations including bed separation to elucidate the role of water in sliding. The hard bedded glacier instrumented in our study exhibited two phases of accelerated sliding motion apparently driven by separate mechanisms. The first acceleration phase (up to 5 fold increase in speed) was closely tied to an increase in bed separation. The faster second phase (up to 9 fold increase in speed) was related to an unusually high level of connectivity of subglacial waters. We infer the first mode was related to cavity opening and the …

Hydrostratigraphy And Groundwater Migration Within Surficial Deposits At The North Lakes Wetland, Hillsborough County, Florida, Jason J. Laroche

USF Tampa Graduate Theses and Dissertations

A wetland in west-central Florida was studied to characterize the local hydrostratigraphic configuration of surficial deposits overlying more-permeable limestones and conceptualize groundwater recharge. Eight continuous cores were drilled through the surficial deposits and partially into the underlying limestone. A total of 111 samples were extracted from the cores for laboratory sediment analyses and testing. The surficial deposits are roughly eight meters thick and made up of upper and lower clean-sand hydrostratigraphic layers (S1 and S3, respectively) separated by a low-permeability layer of clayey sand (S2). Also, a discontinuous low-permeability layer of clayey sand (S4) lies between S3 and the top …

A 2650-Year-Long Record Of Environmental Change From Northern Yellowstone National Park Based On A Comparison Of Multiple Proxy Data, Cathy Whitlock, Walter Dean, Joseph Rosenbaum, Lora Stevens, Sherilyn C. Fritz, Brandi Bracht, Mitchell Power

Department of Earth and Atmospheric Sciences: Faculty Publications

Geochemical, stable-isotope, pollen, charcoal, and diatom records were analyzed at high-resolution in cores obtained from Crevice Lake, a varved-sediment lake in northern Yellowstone National Park. The objective was to reconstruct the ecohydrologic, vegetation, and fire history of the watershed for the last 2650 years to better understand past climate variations at the forest-steppe transition. The data suggest a period of limited bottom-water anoxia, relatively wet winters, and cool springs and summers from 2650 to 2100 cal yrBP (700–150 BC). Dry warm conditions occurred between 2100 and 850–800 cal yrBP (150 BC and AD 1100–1150), when the lake was anoxic, winter …

Along-Strike Trace Element And Isotopic Variation In Aleutian Island Arc Basalt: Subduction Melts Sediments And Dehydrates Serpentine, Brad S. Singer, Brian R. Jicha, William P. Leeman, Nick W. Rogers, Matthew F. Thirlwall, Jeffrey G. Ryan, Kirsten E. Nicolaysen

Geology Faculty Publications

Trace element and Sr-Nd-Pb isotope compositions of basaltic lavas from 11 volcanoes spanning 1300 km of the Aleutian Island arc provide new constraints on the recycling of elements in melts and fluids derived from subducted oceanic crust and sediment. Despite a nearly twofold variation in the flux of sediment subducted along the Aleutians, proxies indicating the presence of sediment melt in the magma source, including Th/La and Th/Nd, do not vary systematically along strike. In contrast, ratios including B/La, B/Nb, B/Be, Cs/La, Pb/Ce, and Li/Y suggest that the quantity or composition of fluid transferred from the slab into the mantle …

Evaluating Discontinuities In Complex Systems: Toward Quantitative Measures Of Resilience, Craig Stow, Craig R. Allen, Ahjond S. Garmestani

United States Geological Survey: Staff Publications

The textural discontinuity hypothesis (TDH) is based on the observation that animal body mass distributions exhibit discontinuities that may reflect the texture of the landscape available for exploitation. This idea has been extended to other complex systems, hinting that the identification and quantification of discontinuities in the distributions of appropriate variables may provide clues to emergent system properties such as resilience. We propose a discontinuity index, based on the vector norm of the full assemblage of observed discontinuities, as a means to quantify and compare this characteristic among systems. We also evaluate four methods to identify the number and location …

Strain And Rotation Rate From Gps In Tibet, Anatolia, And The Altiplano, Richard W. Allmendinger, Robert Reilinger, John P. Loveless

Geosciences: Faculty Publications

Deformation measured by regional GPS networks in continental plateaus reflects the geologic and tectonic variability of the plateaus. For two collisional plateaus (Tibet and Anatolia) and one noncollisional (the Altiplano), we analyze the regional strain and rotation rate by inverting GPS velocities to calculate the full two-dimensional velocity gradient tensor. To test the method, we use gridded velocities determined from an elastic block model for the eastern Mediterranean/Middle East region and show that to a first order, the deformation calculated directly from the GPS vectors provides an accurate description of regional deformation patterns. Principal shortening and extension rate axes, vertical …

Dendrochronological Analysis Of Oak (Quercus) Tree Cross-Sections From The Victor Crouso Field, Wayne County, Ohio

Historic Structures

Dating historical structures in Wayne County, Ohio using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Belding, Elyssa; Wiles, Greg

Mapping Middle Paleozoic Erosional And Karstic Patterns With 3-D Seismic Attributes And Well Data In The Arkoma Basin, Oklahoma, Alonzo R. Brinkerhoff

Theses and Dissertations

Newly available industry well data and seismic attribute analysis reveal that late Ordovician-early Devonian Hunton Group strata are more widespread (i.e., not removed by mid-Devonian erosion) in the central and southern portions of the Arkoma Basin in eastern Oklahoma than previously thought. This study demonstrates the value of applying seismic attribute analysis to problems of quantifying and mapping stratigraphic features caused by erosions and/or karstification. Well and seismic isochron data in the Red Oak petroleum field for the Viola-Woodford interval (the units that lie stratigraphically beneath and above, respectively, the Huton Group) show isolated ~40-m thick lenses of Hunton rocks, …

Dendrochronological Analysis Of White Oak Tree (Quercus Alba) Cores From The Mizer Log Cabin, Coshocton County, Ohio

Historic Structures

Dating historical structures in Coshocton County, Ohio using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Belding, Elyssa; Wiles, Greg.

Dendrochronological Analysis Of The Strouse Barn, Holmes County, Ohio

Historic Structures

Dating historical structures in Holmes County, Ohio using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Belding, Elyssa; Wiles, Greg

Laboratory Based Chemical And Isotopic Investigations On Biotic (Microbial) And Abiotic Reduction Of Iron And Oxidation Of Organic Compounds, Tsigabu Asmelash Gebrehiwet

Dissertations

Studies using chemical and isotopic techniques have been conducted to investigate experimental microbial (biotic) iron reduction and abiotic redox processes. In the microbially mediated study Fe(III) reduction and lactate oxidation at circum-neutral pH and anaerobic conditions were used to characterize the metabolic pathways followed by dissimilatory Fe⁺³ -reducing bacterium Shewanella putrefaciens strain 200R. Iron (II), Iron (III), dissolved inorganic carbon (DIC) and carbon isotope ratios were measured under bicarbonate and phosphate buffered conditions. Carbon isotope disproportionation among organic carbon substrate (lactate), biomass and respired carbon dioxide at the lag to stationary phase of the microbial growth curve showed …

Inside Front & Back Covers: Changes And Variability Of Urban Sprawl - Implications For Local Climate Change, Robert Hellström

Bridgewater Review

No abstract provided.

Influence Of Lithophysal Geometry On The Uniaxial Compression Of Tuff-Like Rock, Douglas B. Rigby, Moses Karakouzian, Amy J. Smiecinski

Publications (YM)

The purpose of this report is to summarize the work and present conclusions of Project Activity Task ORD-FY04-013 conducted under Cooperative Agreement No. DEFC28- 04RW12232 between the U.S. Department of Energy and the Nevada System of Higher Education (NSHE). This document describes results of laboratory testing on analog lithophysal tuff (Hydro-StoneTB®) conducted in the Department of Civil and Environmental Engineering of the University of Nevada at Las Vegas (UNLV) from 2004 to 2006.

Some Applications Of Gaussian Quadrature And Neural Network Modeling In Earth Flows And Other Slow-Moving Landslides In Cohesive Slope Materials, Rennie Bwalya Kaunda

Dissertations

Geometrical changes and progressive displacements in earth flows and other slow moving landslides triggered by climatic changes may be addressed by digital modeling. Gaussian quadrature, a numerical integration technique though fixed points, is employed to compute geometrical areas defined by stratigraphic (soil or rock layering) units, vertical pole projections and a slip surface, based on kinematic admissibility. An example from the Lake Michigan coast shows that the total internal geometrical area is found to be preserved during the course of the progressive deformation. Displacement monitoring of the slope shows that it became less stable over a period of eleven years …

Towards A Better Understanding Of The Hydrology Of The Tigris- Euphrates System And Its Marshlands, Christopher K. Jones

Masters Theses

Rising demands for fresh water supplies are leading to water management practices that are altering natural flow systems world-wide. One of the most devastated of these natural systems is the Tigris-Euphrates watershed that over the past three decades has witnessed the construction of over 60 engineering projects that eliminated seasonal flooding, reduced natural flow and dramatically reduced the areal extent (1966: 11000 km² ; 2002: 750 km²) of the Mesopotamian Marshes downstream. We constructed a continuous (1964 to 1998) catchment-based rainfall runoff model for the entire Tigris-Euphrates watershed (area: one million km²) using the SWAT …

Modeling Effects Of Channel Complexity And Hyporheic Flow On Stream Temperatures, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

Stream temperatures are affected by multiple forcing functions, including surface heat exchange (including solar radiation, evaporation, conduction, and net long wave radiation) and hyporheic flows. Each of these forcing functions is directly influenced by the level of channel complexity in the stream channel and riparian shading. The interrelationship between channel complexity, hyporheic flow and stream temperature is highly complex, and efforts to manage for habitat diversity by managing channel complexity could result in unintended consequences on stream temperature. When planning modifications to stream channel complexity, consideration should be given to the effects such moderations could have on stream temperatures.

Urbanization …

Seismic Field Survey Of The Ground Of The National Research Institute Of Astronomy And Geophysics, Mohamed Said Hanno

Archived Theses and Dissertations

No abstract provided.

Sea Surface Pco2‐Sst Relationships Across A Cold‐Core Cyclonic Eddy: Implications For Understanding Regional Variability And Air‐Sea Gas Exchange, Feizhou Chen, Wei‐Jun Cai, Claudia R. Benitez-Nelson, Yongchen Wang

Faculty Publications

[1] This study is designed to improve the understanding of how biologically productive, cold‐core cyclonic eddies affect sea surface pCO2 in the lee of the main Hawaiian Islands in the subtropical North Pacific Gyre. We identified three unique relationships between pCO2 and sea surface temperature (SST). A positive correlation between pCO2 and SST was observed in the waters surrounding the eddy suggesting surface CO2 is controlled primarily by thermodynamics. In contrast, a negative relationship was observed within the eddy core as a result of the upwelling of CO2‐enriched subsurface waters. A third relationship existed throughout the rest …

Slides: The Future Of Federal Wetlands Regulation, Mark Squillace

The Future of Federal Wetlands Regulation After Rapanos (May 10)

Presenter: Professor Mark Squillace, Director, Natural Resources Law Center, University of Colorado School of Law

35 slides

Agenda: The Future Of Federal Wetlands Regulation After Rapanos, University Of Colorado Boulder. Natural Resources Law Center

The Future of Federal Wetlands Regulation After Rapanos (May 10)

Hot-Topic Discussion held at Brownstein Hyatt Farber Schreck in Denver, Colorado on May 10, 2007 from 12:00 p.m. to 1:15 p.m.

Speaker: Mark Squillace, Director of the Natural Resources Law Center, University of Colorado School of Law.

Commentators: Wayne Forman and Michelle Kales, attorneys, Brownstein Hyatt Farber Schreck

"Rapanos v. United States, 547 U.S. 715 (2006), was a United States Supreme Court case challenging federal jurisdiction to regulate isolated wetlands under the Clean Water Act. It was the first major environmental case heard by the newly appointed Chief Justice, John Roberts and Associate Justice, Samuel Alito. The Supreme Court …

Origin And Tectonic Evolution Of Gondwana Sequence Units Accreted To The Banda Arc: A Structural Transect Through Central East Timor, Elizabeth Anick Zobell

Theses and Dissertations

Petrographic and age analysis of sandstones, detailed structural analysis and gravity modeling were conducted to investigate the origin of the Gondwana Sequence in the Timor Region, and to better constrain the tectonic evolution of the active Banda Arc. Our field studies and U/Pb zircon age analysis helped assign most units to either Asian or Australian affinity. Detrital zircon from uplifted Banda forearc units (Asian affinity) have U/Pb ages as young as 80 Ma (Standley and Harris, in press). In contrast, analysis of detrital zircon from Gondwana Sequence sandstones accreted to the Banda Arc from Savu to East Timor are no …

Dendrochronological Analysis Of Oak (Quercus) Tree Cores From The Wilsford Barn, Shreve, Wayne County, Ohio

Historic Structures

Dating historical structures in Wayne County, Ohio using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Belding, Elyssa; Wiles, Greg

Dendrochronological Analysis Of Oak Tree (Quercus) Beams From The Original Schumaker Cabin, Coshocton County, Ohio

Historic Structures

Dating historical structures in Coshocton County, Ohio using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Belding, Elyssa; Wiles, Greg.

Dendrochronological Analysis Of Oak (Quercus) Beams From The Coshocton (Darr) Log Barn, Coshocton County, Ohio

Historic Structures

Dating historical structures in Coshocton County, Ohio using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Belding, Elyssa; Wiles, Greg.

Dendrochronological Analysis Of Oak (Quercus) Tree Cores And Cross-Sections From The Larry Reed Log Barn, Noble County, Ohio

Historic Structures

Dating historical structures in Noble County, Ohio using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Belding, Elyssa; Wiles, Greg

High-Resolution Stratigraphy At A Coastal Drillhole, Beth Wrege

All Theses

Lithologic descriptions of continuous core interpreted in conjunction with borehole geophysical logs were used to determine thicknesses of hydrologic and geologic units at CR-622 in the coastal plain of North Carolina. Borehole geophysics was used to adjust the position of core loss within each cored interval and to supplement lithology to determine the stratigraphy of missing segments of core. Although some geophysical logs produce non-unique lithologic solutions, a complete normal stratigraphic profile may be obtained with the addition of continuous core. Curve characteristics within geophysical logs provide precise identification of transitional sequences and can be used to calibrate lithostratigraphy. The …

An Analysis Of Key Aspects Of Warm And Cool Season Flash Flooding In The Southern Appalachians, William Baldwin

Masters Theses & Specialist Projects

Flash flooding kills more people in the United States than any other severe weather phenomenon. One of the most vulnerable areas for flooding is the southern Appalachians. These mountains lie in a geographical location that places them near the Atlantic Ocean and the Gulf of Mexico, two major moisture source regions. This ample supply of moisture, mid-latitude circulation patterns, and orographic lifting leads to annual precipitation totals in the southern Appalachians that are comparable to locations along the Gulf coast. The present study investigates eight non-tropical flash flood events. Four of the events occurred in the cool season and four …

Storm Response And Water Balance Of Temperate Rainforest Karst Watersheds: Tongass National Forest, Alaska, Johanna Kovarik

Masters Theses & Specialist Projects

The Tongass National Forest in southeast Alaska contains 2,176 square kilometers of karst. As part of the evolving Tongass Land Management Plan, research into the function of karst systems is crucial in understanding how forest management affects not only karst areas but also surrounding ecosystems. Dye trace and water balance results in two watersheds on the north end of Prince of Wales Island demonstrate the difficulty in containing the effects of management, as water can enter karst catchments from unknown sources at different flow regimes. A dye trace was conducted in Windgate and Canyon Block watersheds. Two sinking streams were …

Agricultural Contaminant Source And Transport In A Karst Groundwater Basin, Patricia Kambesis

Masters Theses & Specialist Projects

Agricultural land use in areas that are located in karst groundwater basins negatively impact groundwater quality because karst terrains provide multiple, direct hydrologic connections from the surface into karst aquifers. The connections and rapid velocities associated with surface and subsurface flow in karst aquifers allow for contaminants to move quickly into and through a groundwater basin. When groundwater returns to the surface via a spring or springs, any contaminants within the water become part of surface streams and rivers. These in turn, impact water quality in areas located downstream of the spring or springs. The purpose of this study was …

Spatio-Temporal Analysis Of Observed Soil Moisture From Nebraska, Ashley Littell

Masters Theses & Specialist Projects

Soil moisture is a measure of the water content in a soil that is dependent upon precipitation, evapotranspiration, runoff, drainage, and irrigation. Nebraska is one of the few states that measures soil moisture in an extensive network that records weather variables on a daily basis. Daily soil moisture observations are collected from depths of 10, 25, 50, and 100 centimeters and analyzed in this research. Data from these stations are evaluated on the spatial and temporal scales using spatial interpolations, time-series analysis, and cross-correlations to better understand the variations of soil moisture in the Northern Great Plains. Spatial interpolation grids …