Physical Sciences and Mathematics Commons^™

Speleothems As Proxy For The Carbon Isotope Composition Of Atmospheric Co2, M. Baskaran, R. V. Krishnamurthy

Environmental Science and Geology Faculty Research Publications

We have measured the stable isotope ratios of carbon in a suite of recent cave deposits (<200 >years) from the San Saba County, Texas, USA. The methodology for dating these deposits using excess ²¹⁰Pb was recently established [Baskaran and Iliffe, 1993]. The carbon isotope ratios of these samples, spanning the time period ∼1800–1990 AD, reflect the carbon isotope ratio of atmospheric CO₂ for the same period. The pathways by which the δ¹³C of atmospheric CO₂ is imprinted on these speleothems can be explained using a model developed by Cerling (1984). The results suggest that the …

Plate Motions In The North Andean Region, Jeffrey T. Freymueller, James N. Kellogg, Victor Vega

Faculty Publications

Repeated geodetic measurements with the Global Positioning System (GPS) provide direct measurements of displacements due to plate motions and active crustal deformation in Central America and northern South America, an area of complex interaction of the Nazca, Cocos, Caribbean and South American plates. The displacement rates for the period 1988-1991, obtained from the results of the first three Central And South America (CASA) GPS campaigns, are in general agreement with the predictions of the NUVEL-1 plate motion model, but there are differences in detail between the observations and the model. The Nazca-North Andes convergence rate vector measured by GPS is …

Changes In Benthic Invertebrate Composition In Response To Reservoir Aging, Arthur Popp

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

Home Range And Movement Charactersistics Of Female White-Tailed Deer At Desoto National Wildlife Refuge, Kurt C. Vercauteren

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

Geology Newsletter- 1993, Department Of Geology

Geological and Environmental Sciences News

Vol.1, No. 18

• Faculty News
• Awards and Scholarships
• Service Staff News
• Hydrogeologic Atlas Available
• Alumni/ Friends/ Former Faculty Notes
• Geology Development and Scholarship Donations

Catchment Management Report Prepared For The Dalwallinu Pithara Land Conservation District, Jenny Borger

Agriculture reports

The Pithara-Dalwallinu Land Conservation District was initiated in 1985. Over the past seven years the committee has carried out various trials, demonstrations and field days. It was decided in 1989 to go along the road of whole catchment planning utilising the Geographic Information System (GIS). It now gives me great pleasure to see the information collected over the last two years, presented as a workable document. I hope now that many farmers within the LCD will be able to use this report to aid in planning and future development of their most valued asset The Land. The Catchment Report is …

Seismic Evidence For Blind Thrusting Of The Northwestern Flank Of The Venezuelan Andes, Bruno De Toni, James N. Kellogg

Faculty Publications

Surface geology and seismic and well data from the northwestern flank of the Venezuelan Andes indicate overthrusting of Andean basement rocks toward the adjacent Maracaibo Basin along a blind thrust fault. The frontal monocline is interpreted as the forelimb of a northwestward verging fault-related fold deformed over a crustal-scarle map. The Andean block has been thrust 20 km to the northwest and uplifted 10 km on a ramp that dips about 20^o-30^o southeastward. The thrust fault ramps up through crystalline basement rocks to a decollement horizon within the shaly units of the Cretaceous Colon-Mito Juan formations. Backthrusts …

Field Test Of A Calcite Dissolution Rate Law: Fort’S Funnel Cave, Mammoth Cave National Park, J. Scott Slunder

Masters Theses & Specialist Projects

The laboratory-derived calcite dissolution rate law of Plummer et al. (1978) is the most widely used and mechanistically detailed expression currently available for predicting dissolution rates as a function of water chemistry. Such rate expressions are of great use in understanding timescales associated with limestone karst development. Little work has gone into the field testing of the rate law under natural conditions.

This work compared measured dissolution rates measured by a crystal weight loss experiment in Buffalo Creek within Fort’s Funnel Cave, which lies within a pristine, forested catchment of Mammoth Cave National Park. Continuous water chemistry sampling over the …

Atmospheric Depositional Fluxes Of 7Be And 210Pb At Galveston And College Station, Texas, M. Baskaran, Charles H. Coleman, Peter H. Santschi

Environmental Science and Geology Faculty Research Publications

The bulk depositional fluxes of ²¹⁰Pb and ⁷Be were measured at a coastal (Galveston) and an inland (College Station) station for about 3 years, between 1989 and 1991. The annual depositional fluxes of ⁷Be and ²¹⁰Pb at Galveston during this period varied by a factor of about 2.5, between 8.9 and 23.2 disintegrations per minute (dpm) cm⁻² yr⁻¹, with a mean of 14.7 dpm cm⁻² yr⁻¹ for ⁷Be, and 0.67 and 1.71 dpm cm⁻² yr⁻¹, with a mean of 1.03 dpm cm⁻² yr⁻¹ for ^{210 …}

Body Size In Amblyrhiza Inundata (Rodentia, Caviomorpha), An Extinct Megafaunal Rodent From The Anguilla Bank, West Indies: Estimates And Implications, Audrone R. Biknevicius, Donald A. Mcfarlane, Ross D. E. Macphee

WM Keck Science Faculty Papers

Rodent species typically evolve larger mean body sizes when isolated on islands, but the extinct caviomorph Amblyrhiza inundata, known only from Quaternary cave deposits on the islands of Anguilla and St. Martin (northern Lesser Antilles), provides an unusually dramatic example of insular gigantism. Here we report on a series of body mass estimates for Amblyrhiza using predictive equations based on anteroposterior diameters and cortical cross-sectional areas of humeral and femoral diaphyses. Analyses of 14 isolated specimens (5 femoral, 9 humeral), all representing adult or near adult animals, yield body mass estimates ranging from slightly less than 50 kg to more …

Petrology And Geochemistry Of Some High Pressure Rocks From Northern Part Of Rio San Juan Complex, Dominican Republic, Khandaker I. Anam

FIU Electronic Theses and Dissertations

The Rio San Juan Complex is an important occurrence of high pressure/low temperature rocks in the circum-Caribbean region which contains both coherent blueschist units and two varieties of melange in the same area. The melanges contain a diverse assemblage of blocks of various sizes, different degrees of metamorphism, and mineral assemblages. Some high pressure blocks show two stages of metamorphism. The earliest stage is characterized by high pressure-low temperature conditions and the second stage is characterized by high pressure-lower temperature conditions. The geochemistry of thirteen samples from the Rio San Juan Complex has been studied and data have been compared …

Anomalous Mesozoic Thermal Regime, Central Appalachian Piedmont: Evidence From Sphene And Zircon Fission-Track Dating, B. P. Kohn, M. E. Wagner, Tim M. Lutz, G. Organist

Earth & Space Sciences Faculty Publications

No abstract provided.

An Integrated Surface And Borehole Seismic Case Study: Fort St. John Graben Area, Alberta, Canada, Ronald C. Hinds, Richard Kuzmiski, Neil Lennart Anderson, Barry R. Richards

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The deltaic sandstones of the basal Kiskatinaw Formation (Stoddard Group, upper Mississippian) were preferentially deposited within structural lows in a regime characterized by faulting and structural subsidence. In the Fort St. John Graben area, northwest Alberta, Canada, these sandstone facies can form reservoirs where they are laterally sealed against the flanks of upthrown fault blocks. Exploration for basal Kiskatinaw reservoirs generally entails the acquisition and interpretation of surface seismic data prior to drilling. These data are used to map the grabens in which these sandstones were deposited, and the horst blocks which act as lateral seals. Subsequent to drilling, vertical …

A Comparison Of No And N20 Production By The Autophic Nitrifier Nitrosomonas Europaea And The Heterotrophic Nitrifier Alcaligenes Faecalis, Iris C. Anderson, Mark Poth, Julie Homstead, David J. Burdige

OES Faculty Publications

Soil microorganisms are important sources of the nitrogen trace gases NO and N₂O for the atmosphere. Present evidence suggests that autotrophic nitrifiers such as Nitrosomonas europaea are the primary producers of NO and N₂O in aerobic soils, whereas denitrifiers such as Pseudomonas spp. or Alcaligenes spp. are responsible for most of the NO and N₂O emissions from anaerobic soils. It has been shown that Alcaligenes faecalis, a bacterium common in both soil and water, is capable of concomitant heterotrophic nitrification and denitrification. This study was undertaken to determine whether heterotrophic nitrification might be …

An Integrated Surface Seismic/Seismic Profile Case Study: Simonette Area, Alberta, Ronald C. Hinds, Neil Lennart Anderson, Richard Kuzmiski

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

On the basis of conventional surface seismic data, the 13-15-63-25W5M exploratory well was drilled into a low-relief Leduc Formation reef (Devonian Wood-bend Group) in the Simonette area, west-central Alberta, Canada. The well was expected to intersect the crest of the reef and encounter about 50-60 m of pay; unfortunately it was drilled into a flank position and abandoned. The decision to abandon the well, as opposed to whipstocking in the direction of the reef crest, was made after the acquisition and interpretive processing of both near-and far-offset (252 and 524 m, respectively) vertical seismic profile (VSP) data, and after the …

Continuous Monitoring Of High‐Temperature Fumaroles On An Active Lava Dome, Volcán Colima, Mexico: Evidence Of Mass Flow Variation In Response To Atmospheric Forcing, Charles B. Connor, Bradford M. Clement, Xiaodan Song, Sammantha B. Lane, Jennifer West-Thomas

School of Geosciences Faculty and Staff Publications

Rapid, multichannel monitoring of fumaroles on Volcán Colima, Mexico, provides new insight into the time‐scales and magnitudes of fumarole temperature variation. Temperatures in five fumaroles, all located along a single fracture cutting the summit lava dome of the volcano, were monitored at 20‐min intervals between May 1991 and May 1992. Measurements were made using a programmable data logger deployed near the fumarole field, and data were radiotelemetered to a nearby volcano observatory at regular intervals. Mean fumarole temperatures varied between 350°C and 550°C. Statistical analysis of these time series shows that significant diurnal variation occurs in each fumarole. Magnitudes of …

Probable Glacial Climatic Conditions In Source Areas During Deposition Of Parts Of The Ash Hollow Formation, Ogallala Group (Late Tertiary), Of Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Evidence of the climatic conditions in the mountain sediment source areas for the late Tertiary Ash Hollow Formation of the Ogallala Group in western Nebraska has been sought in an SEM (scanning electron microscope) study of surface features on detrital quartz grains from these deposits. The following lines of indirect evidence raised the possibility of glacial conditions: uplift of up to 3500 m in the source areas, paleohydrologic parameters indicative of a transport system analogous to the modern North Saskatchewan River, and possible cold climate surface features on cobbles from the deposits. SEM analysis shows that five of the nine …

Gps Measurement Of Relative Motion Of The Cocos And Caribbean Plates And Strain Accumulation Across The Middle America Trench, Timothy H. Dixon

School of Geosciences Faculty and Staff Publications

Global Positioning System (GPS) measurements in 1988 and 1991 on Cocos Island (Cocos plate), San Andres Island (Caribbean plate), and Liberia (Caribbean plate, mainland Costa Rica) provide an estimate of relative motion between the Cocos and Caribbean plates. The data for Cocos and San Andres Islands, both located more than 400 km from the Middle America Trench, define a velocity that is equivalent within two standard errors (7 mm/yr rate, 5 degrees azimuth) to the NUVEL-1 plate motion model. The data for Liberia, 120 km from the trench, define a velocity that is similar in azimuth but substantially different in …

Mapping The Distribution Of Vesicular Textures On Silicic Lavas Using The Thermal Infrared Multispectral Scanner, Jaime Ondrusek, Philip R. Christensen, Jonathan Fink

Geology Faculty Publications and Presentations

The Thermal Infrared Multispectral Scanner (TlMS) is a potentially powerful tool for mapping detailed chemical variations in silicic lava flows which in turn could expand knowledge of pre-eruption compositional gradients and mixing processes in silicic magma bodies. However, thermal infrared image data may be greatly influenced by the range of vesicular textures which occur on silicic flows . To investigate the effect of vesicularity on TIMS imagery independent of chemical variations, we studied Little Glass Mountain at the Medicine Lake Volcano of northern California, a large rhyolitic flow of uniform composition but textural heterogeneity. The imagery was recalibrated so that …

Chloroform Contamination In The Louisville Aquifer: An Investigation Of Its Occurrence And Propagation, Sergio E. Serrano

KWRRI Research Reports

This report presents the main results of an investigation on the nature and propagation of an accidental spill of chloroform in the Louisville aquifer, Kentucky. Much of the effort is concentrated on the development of mathematical models to either reconstruct the history of evolution of the plume, or forecast its propagation in the future. Chloroform is a dense halogenated solvent which exhibits a special migration pattern in porous media: Because of this and the relative absence of a conceptual theory on its hydrodynamics in porous media, meaningful predictive models will have to deal with many unresolved theoretical aspects of contaminant …

Epa's Map Of Radon Zones, Nebraska, Sharon W. White, Lisa Ratcliff, Kirk Maconaughey, R. Thomas Peake, Dave Rowson, Steve Page, Linda C. S. Gundersen, R. Randall Schumann, James K. Otton, Doug Owen, Russell Dubiel, Kendell Dickinson, Sandra L. Szarzi

United States Environmental Protection Agency: Staff Publications

Sections 307 and 309 of the 1988 Indoor Radon Abatement Act (IRAA) direct EPA to identify areas of the United States that have the potential to produce elevated levels of radon. EPA, the U.S. Geological Survey (USGS), and the Association of, American State Geologists (AASG) have worked closely over the past several years to produce a series of maps and documents which address these directives. The EPA Map of Radon Zones is a compilation of that work and fulfills the requirements of sections 307 and 309 of IRAA. The Map of Radon Zones identifies, on a county-by-county basis, areas of …

Virginia Beach Offshore Sediment Study, C. R. Berquist Jr., Naomi Gomillion

Reports

This investigation was initiated from discussions among members of the Minerals Management Service-Virginia Task Force in an effort to locate a nearby and offshore source of beach-quality sand for the resort strip at Virginia Beach. Because of the increasing difficulty of relying upon land-based material, attention has been focused on investigating offshore sources. Previous work (Kimball and others, 1991) suggests an offshore deposit of beach-quality sands is located on a shoal between 3 and 8 km east of Sandbridge. Planned vibracoring on this shoal during the fall of 1993 should establish the viability of the sand occurrence. Although material from …

An Overview Of Some Of The Large Scale Mechanisms Of Salt Dissolution In Western Canada, Neil Lennart Anderson, Ralph W. Knapp

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Well log and seismic data indicate that the bedded rock salts of the Devonian Prairie Formation were widely distributed and uniformly deposited in the Lloydminster area, Western Canada; however, as a result of extensive leaching, the distribution of these salts is not now what it once was. The Lloydminster area is now bisected by the north-south trending main dissolutional edge of the Prairie salt. Thick salt (up to 150 m) is preserved to the west of this edge; to the east the salt is mostly absent. The paper presents an overview of the envisioned principal mechanisms of salt dissolution. The …

Epa's Map Of Radon Zones Nebraska, U.S. Environmental Protection Agency's, U.S. Geological Survey

United States Environmental Protection Agency: Staff Publications

Sections 301 and 309 of the 1988 Indoor Radon Abatement Act (IRAA) direct EPA to identify areas of the United States that have the potential to produce elevated levels of radon. EPA, the U.S. Geological Survey (USGS), and the Association of. American State Geologists (AASG) have worked closely over the past several years to produce a series of maps and documents which address these directives. The EPA Map of Radon Zones is a compilation of that work and fulfills the requirements of sections 307 and 309 of IRAA. The Map of Radon" Zones identifies, on a county-by-county basis, areas' of …

Limnological And Habitat Influences On Wetland Bird Communities In The Nebraska Sandhills, Timothy A. Cramer

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

Odp Leg 146 Examines Fluid Flow In Cascadia Margin, Bernard A. Housen

Geology Faculty Publications

For the better part of 2 decades, it has been known that dewatering of sediments accreted to or subducted beneath accretionary wedges is a fundamental aspect of the subduction-accretion process. Yet, evidence for fluid flow in modern accretionary wedges is largely secondary and based on the presence of geochemical and/or thermal anomalies [e.g., Vrolijk et al., 1991]; the analysis of seismic velocity as an indicator of porosity, which suggests a progressive loss of pore volume in a landward direction [e.g., Bray and Karig, 1985]; and the occurrence of secondary sediment microstructures characteristic of fluid movement [e.g., Maltman et …

Evolution Of The Naticid Gastropod Predator-Prey System: An Evaluation Of The Hypothesis Of Escalation, Patricia H. Kelley, Thor A. Hansen

Geology Faculty Publications

Previous work has suggested that escalation may have characterized the history of the naticid gastropod predator-prey system, based on apparent increases in drilling frequencies and the occurrence of antipredatory aptations among prey. We evaluate this hypothesis based on a comprehensive survey (over 40,000 specimens) of predation on molluscs from the Upper Cretaceous through lower Oligocene formations within the U.S. Gulf and Atlantic Coastal Plain. Patterns in drilling of both bivalve and gastropod prey are complex. Drilling frequencies were relatively low in the Cretaceous but increased sharply above the Cretaceous-Tertiary boundary, remaining high until the late Eocene. Following a significant decline …

Groundwater Velocity In An Unconfined Aquifer With Rectangular Areal Recharge, Vitaly A. Zlotnik, Glenn Ledder

Department of Earth and Atmospheric Sciences: Faculty Publications

Three-dimensionsal solutions for the hydraulic head and velocity components for transient groundwater flow in an unconfined compressible aquifer of finite thickness with a rectangular areal recharge source are analyzed using a linearized mathematical model. The solution generalizes Dagan's (1967) results, which were obtained for an idealized aquifer of infinite thickness, and Hantush's (1967) results, which were derived using the Dupuit assumptions. Hydraulic head and velocity components are estimated by asymptotic methods for large times, which are most appropriate for contaminant transport problems. Numerical analysis of the solution demonstrates spatial features of the velocity components in general and a transient effect …

Geology, Geologic Time And Nebraska, Marvin P. Carlson

Conservation and Survey Division

No abstract provided.

Regional Distribution Of Monsoon And Desert Dust Signals Recorded In Asian Glaciers, Cameron P. Wake, Paul Andrew Mayewski, Xie Zichu, Wang Ping, Li Zhongquin

Earth Science Faculty Scholarship

Short‐term (6 months to 17 years) glaciochemical records have been collected from glacier basins throughout the mountains of central Asia. The spatial distribution of snow chemistry in central Asia is controlled predominantly by the influx of dust from the arid and semi‐arid regions in central Asia. The glaciochemical data suggests that glaciers which are removed from large source areas of mineral aerosol, such as those in the Himalaya, the Karakoram, and the southeastern Tibetan Plateau, are the ones most likely to contain longer‐term glaciochemical records which detail annual to decadal variation in the strength of the Asian monsoon and long‐range …