Geology Commons^™

Caves And Karsts Of Northeast Africa, William R. Halliday

International Journal of Speleology

At least potentially karstifiable rocks cover much of the surface of Egypt and northern Libya. Study of caves and other karstic features of this region has been hampered by lack of roads, rapid disintegration of the surface of friable, poorly consolidated limestone, wind-blown sand and other factors. Interbedding with marly aquicludes hampers speleogenesis locally. Calcareous and evaporite karsts are present, however, and their waters are important albeit generally limited resources. Large quantities of fresh water are lost through submarine springs downslope from Libya’s Gebel al Akhdar range; the caves and karst of that range may be among the world’s greatest. …

Annual Inflow Of Water To Nebraska And Annual Outflow Of Water From Nebraska, 1950 - 2003, S. E. Summerside, W. Myers, S. Olafsen-Lackey

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Lancaster County Test Hole Logs, Raymond R. Burchett, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Subglacial Thermal Balance Permits Ongoing Grounding Line Retreat Along The Siple Coast Of West Antarctica, Byron R. Parizek, Richard B. Alley, Christina L. Hulbe

Geology Faculty Publications and Presentations

Changes in the discharge of West Antarctic ice streams are of potential concern with respect to global sea level. The six relatively thin, fast-flowing Ross ice streams are of interest as low-slope end-members among Antarctic ice streams. Extensive research has demonstrated that these "rivers of ice" have a history of relatively high-frequency (óO(100) years), asynchronous discharge variations with evolving lateral boundaries. Amidst this variability, a ~1300 km grounding-line retreat has occurred since the Last GlacialMaximum. Numerical studies of Ice Stream D (Parizek and others, 2002) indicate that a proposed thermal-regulation mechanism(Clarke and Marshall, 1998; Hulbe and MacAyeal,1999; Tulaczyk and others, …

Extensional Folds Associated With Paleogene Detachment Faults In Se Part Of The Salmon Basin, Susanne U. Janecke, J. C. Blankenau

Geosciences Faculty Publications

No abstract provided.

Multivariate Geostatistical Analysis With Application To A Western Australian Nickel Laterite Deposit, Ellen Bandarian

Theses : Honours

Although it can be time consuming and computationally more expensive to work with multivariate data, it is often desirable to exploit the relationships among and between the variables sampled across a study region. In most cases the availability of this secondary information can enhance the estimation of the primary variable(s). The aim of this research is to describe and then demonstrate the use of multivariate statistical methods in geostatistical analysis. The methods will be illustrated by application to a multivariate data set from an actual mineralisation. The data suite is known as MM22D and comes from the Murrin Murrin nickel …

Complex Decapod Burrows And Ecological Relationships In Modern And Pleistocene Intertidal Carbonate Environments, San Salvador Island, Bahamas, H. Allen Curran, Anthony J. Martin

Geosciences: Faculty Publications

Burrowing by thalassinidean shrimp in modern tropical, shallow-subtidal to intertidal carbonate environments is widespread and a powerful agent of bioturbation, particularly within sandy substrates. Deep and intense burrowing by callianassids commonly occurs along the intertidal margins of hypersaline lagoons throughout the Bahamas, such as Pigeon Creek on San Salvador Island, where the sediments of extensive sand flats are thoroughly bioturbated by Glypturusacanthochirus. In addition to dominating the deep-tier infauna, G. acanthochirus is a true ecosystem engineer, and its prodigious burrowing activity results in a highly mounded topography. On sand flats, individual sediment cones commonly coalesce with time to form large …

Glacial Deposits, Vol. 31, 2002-2003, Department Of Geography-Geology

Glacial Deposits

Newsletter of the Department of Geography-Geology

Martel's Routes In Mammoth Cave, Kentucky, 1912, Trevor R. Shaw

International Journal of Speleology

Martel’s own copy of the Hovey 1912 guidebook to Mammoth Cave has his routes marked faintly in pencil on the printed cave plans. These plans are reproduced here, with his routes indicated on them. He generally followed the four standard tourist routes which now included Kaemper’s 1908 discoveries to Violet City, but instead of visiting the Maelstrom he went to Hovey’s Cathedral and Gerta’s Grotto.

Human Impact On Karst: The Example Of Lusaka (Zambia), Jo De Waele, Roberto Follesa

International Journal of Speleology

Lusaka, the capital of Zambia with over 2,000,000 inhabitants, is built on an extensive plateau composed mainly of schists and dolomitic marbles, constituting a very important aquifer that provides the city with almost half of its drinking water needs. Recent demographic growth, leading to uncontrolled urban expansion, and mismanagement of the water resource and of urban waste has lead, in the past 20 years, to an overexploitation of the aquifer and to a generalised water quality depletion, putting in serious danger the future social and economical development of the capital. This third world city has, for these reasons, become a …

The Role Of Lateral And Vertical Shear In Tributary Flow Toward A West Antarctic Ice Stream, Christina L. Hulbe, Weili Wang, Ian R. Joughin, Martin J. Siegert

Geology Faculty Publications and Presentations

Narrow lateral shear margins are the most distinctive visual feature of the West Antarctic ice streams. Large shear stresses within these layers support the majority of the gravitational driving stress within a fast-flowing ice stream.The present contribution looks upstream, to the tributaries that feed ice-stream onsets, and considers the effects of both horizontal and vertical shear on their flow. Numerical and direct simulations of vertical and horizontal shear are used.Vertical shear, simulated using an anisotropic flow law, is of particular interest.We conclude that by isolating overlying ice from large-amplitude variations in bed elevation -vertical shear margins - play an important …

Anisotropic Ice Flow Leading To The Onset Of Ice Stream D, West Antarctica: Numerical Modelling Based On The Observations From Byrd Station Borehole, Weili Wang, H. Jay Zwally, Christina L. Hulbe, Martin J. Siegert, Ian R. Joughin

Geology Faculty Publications and Presentations

An ice-sheet flowline model is used to simulate the flow of ice along two particle paths toward the onset to Ice Stream D,West Antarctica. One path is near the centre line of the main tributary to the ice stream, while the second passes by the Byrd Station borehole site. In this paper, we analyze the flow of the moderately fast-flowing tributaries in terms of ice-fabric anisotropy and estimate the steady-state ice-flow regions with the compatible developed crystal orientation fabrics along two particle paths. Comparison between modelled isochrones and internal layers detected from radio-echo sounding surveys in the area is used …

2003 Changes To Water Transfer Law In Nebraska- Addendum, J. Michael Jess

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Identification Of Gypsy Moth Defoliation In Ohio Using Landsat Data, Angela Lorraine Hurley

Browse all Theses and Dissertations

The gypsy moth is one of the most devastating forest pests in North America. In late spring, gypsy moth larvae hatch from eggs laid the previous summer. During the next forty days, tens of thousands of these caterpillars eat up to one square foot of foliage each. The gypsy moth has established populations in several states, and dangerously fast-growing populations in several others. The state of Ohio is a critical area in the suppression of the gypsy moth because the front of gypsy moth advance passes through the state. Besides diminishing the aesthetic value of Ohio’s forests, gypsy moths also …

A Reconnaissance Scale Assessment Of Confining Conditions Within The Ground-Water System Of The Principal Aquifer In The Upper Big Blue Nrd, S. E. Summerside, R. Vasek, D. C. Gosselin, J. M. Jess

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Butler County Test Hole Logs, Scott E. Summerside, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Nuckolls County Test Hole Logs, Scott E. Summerside

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Seward County Test Hole Logs, Raymond R. Burchett, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Calibration Of Remotely Sensed, Coarse Resolution Ndvi To Co2 Fluxes In A Sagebrush–Steppe Ecosystem, Bruce K. Wylie, Douglas A. Johnson, Emilio Laca, Nicanor Z. Saliendra, Tagir G. Gilmanov, Bradley C. Reed, Larry L. Tieszen, Bruce B. Worstell

United States Geological Survey: Staff Publications

The net ecosystem exchange (NEE) of carbon flux can be partitioned into gross primary productivity (GPP) and respiration (R). The contribution of remote sensing and modeling holds the potential to predict these components and map them spatially and temporally. This has obvious utility to quantify carbon sink and source relationships and to identify improved land management strategies for optimizing carbon sequestration. The objective of our study was to evaluate prediction of 14-day average daytime CO₂ fluxes ( F_day) and nighttime CO₂ fluxes (R_n) using remote sensing and other data. F_{day …}

An Approach For Mapping Large-Area Impervious Surfaces: Synergistic Use Of Landsat-7 Etm+ And High Spatial Resolution Imagery, Limin Yang, Chengquan Huang, Bruce K. Wylie, Michael J. Coan

United States Geological Survey: Staff Publications

A wide range of urban ecosystem studies, including urban climate, land use planning, and resource management, require current and accurate geospatial data of urban impervious surfaces. We developed an approach to quantify urban impervious surfaces as a continuous variable by using multisensor datasets. Subpixel percent impervious surfaces at 30-m resolution were mapped using a regression tree model. The utility, practicality, and affordability of the proposed method for large-area imperviousness mapping were tested over three spatial scales (Sioux Falls, South Dakota, Richmond, Virginia, and the Chesapeake Bay areas of the United States). Average error of predicted versus actual percent impervious surface …

Influence Of The Pacific Decadal Oscillation On The Climate Of The Sierra Nevada, California And Nevada, Larry Benson, Braddock Linsley, Joe Smoot, Scott Mensing, Steve Lund, Scott Stine, Andre Sarna-Wojcicki

United States Geological Survey: Staff Publications

Mono Lake sediments have recorded five major oscillations in the hydrologic balance between A.D. 1700 and 1941. These oscillations can be correlated with tree-ring-based oscillations in Sierra Nevada snowpack. Comparison of a tree-ring-based reconstruction of the Pacific Decadal Oscillation (PDO) index (D’Arrigo et al., 2001) with a coral-based reconstruction of Subtropical South Pacific sea-surface temperature (Linsley et al., 2000) indicates a high degree of correlation between the two records during the past 300 yr. This suggests that the PDO has been a pan-Pacific phenomena for at least the past few hundred years. Major oscillations in the hydrologic balance of the …

Age Of The Mono Lake Excursion And Associated Tephra, Larry Benson, Joseph Liddicoat, Joseph Smoot, Andrei Sarna-Wojcicki, Robert M. Negrini, Steve Lund

United States Geological Survey: Staff Publications

The Mono Lake excursion (MLE) is an important time marker that has been found in lake and marine sediments across much of the Northern Hemisphere. Dating of this event at its type locality, the Mono Basin of California, has yielded controversial results with the most recent effort concluding that the MLE may actually be the Laschamp excursion (Earth Planet. Sci. Lett. 197 (2002) 151). We show that a volcanic tephra (Ash #15) that occurs near the midpoint of the MLE has a date (not corrected for reservoir effect) of 28,620 ± 300 ¹⁴C yr BP (~32,400 GISP2 yr BP) …

Rare-Earth Elements And Nd And Pb Isotopes As Source Indicators For Labrador Sea Clay-Size Sediments During Heinrich Event 2, Larry V. Benson, Don Barber, John T. Andrews, Howard E. Taylor, Paul Lamothe

United States Geological Survey: Staff Publications

Elemental abundances and Nd and Pb isotope ratios were determined on samples from the carbonate-free, clay-size fractions of sediments from intervals above, within, and below Heinrich event 2 (H-2) in core HU87-9 from the Northwest Labrador Sea slope. In HU87-9, rare-earth element (REE) distributions and elemental concentrations within the H-2 event are distinct from those outside this event. ɛ_Nd(0) and ²⁰⁶Pb/²⁰⁴Pb data also indicate different values for sediments deposited within and outside the H-2 event. Comparisons of REE patterns from the H-2 interval with those from bedrock units in Baffin Island, northern Quebec, and Labrador …

Response Of North American Great Basin Lakes To Dansgaard–Oeschger Oscillations, Larry Benson, Steve Lund, Robert M. Negrini, Braddock Linsley, Mladen Zic

United States Geological Survey: Staff Publications

We correlate oscillations in the hydrologic and/or cryologic balances of four Great Basin surface-water systems with Dansgaard– Oeschger (D–O) events 2–12. This correlation is relatively strong at the location of the magnetic signature used to link the lake records, but becomes less well constrained with distance/time from the signature. Comparison of proxy glacial and hydrologic records from Owens and Pyramid lakes indicates that Sierran glacial advances occurred during times of relative dryness. If our hypothesized correlation between the lake-based records and the GISP2 δ¹⁸O record is correct, it suggests that North Atlantic D–O stades …

Aeolian Cliff-Top Deposits And Buried Soils In The White River Badlands, South Dakota, Usa, J. Elmo Rawling Iii, Glen G. Fredlund, Shannon Mahan

United States Geological Survey: Staff Publications

Aeolian deposits in the North American Great Plains are important sources of Holocene palaeoenvironmental records. Although there are extensive studies on loess and dune records in the region, little is known about records in aeolian cliff-top deposits. These are common on table (mesa) edges in the White River Badlands. These sediments typically have loam and sandy-loam textures with dominantly very fine sand, 0.5–1% organic carbon and 0.5–5% CaCO₃. Some of these aeolian deposits are atypically coarse and contain granules and fine pebbles. Buried soils within these deposits are weakly developed with A-C and A-AC-C profiles. Beneath these are …

New Record Of The Rare Emballonurid Bat Centronycteris Centralis Thomas, 1912 In Costa Rica, With Notes On Feeding Habits, Neal Woodman

United States Geological Survey: Staff Publications

The shaggy sac-winged bat, Centronycteris centralis (Chiroptera: Emballonuridae), occurs mainly in lowland forests from Veracruz, Mexico, to Peru, although it has been reported from elevations as high at 1450 m in Panama (Simmons and Handley 1998; Hice and Solari 2002). Most captures of the species are of single individuals, and throughout its distribution, this bat is rare and poorly-known (Emmons 1997; Reid 1997; Simmons and Handley 1998). Centronycteris centralis generally has been assumed to be an aerial insectivore, capturing flying insects on the wing (Starrett and Casebeer 1968; Wilson 1973; Timm et al. 1989; LaVal and Rodrı´guez 2002). However, direct …

Quaternary Loess-Paleosol Sequences As Examples Of Climate-Driven Sedimentary Extremes, Daniel R. Muhs, E. Arthur Bettis Iii

United States Geological Survey: Staff Publications

Loess is a widespread, wind-transported, silt-dominated deposit that contains geologic archives of atmospheric circulation and paleoclimate on continents. Loess may cover as much as 10% of the Earth’s land surface. It is composed mainly of quartz, feldspars, and clay minerals, with varying amounts of carbonate minerals. The geochemistry of loess differs from region to region, depending on source materials, but all loess is very high in SiO2 with lesser amounts of other major elements. Trends in loess downwind from source areas include systematic decreases in thickness and amounts of sand and coarse silt, and increases in amounts of fine silt …

Effect Of Geochemical Processes And Environment On The Spatial Pattern Of Selenium In Soil, Surface Water, And Groundwater At The Hovland Ranch, Central South Dakota, Salah U. Sharif

Theses and Dissertations

The objective of this paper is to test and review some of the published hypotheses as that may relate to selenium geochemistry in soil and water system at the Hovland Ranch, Haakon County, South Dakota. Representative samples were collected from soil, water, and soil moisture in the field. Preparation of samples and chemical analysis were done in the Water Quality Laboratory, Dept. of Geology and Geological Engineering, University of North Dakota and Human Nutrition Research Center Lab, USDA/ARS, Grand Forks, North Dakota. The analysis results were statistically analyzed to find correlation between the occurrence of selenium and other associated chemical …

Numerical And Granulometric Approaches To Geophysical Granular Flows , Sébastien Dartevelle

Dissertations, Master's Theses and Master's Reports - Open

Volcanic ash clouds can be fed by an upward-directed eruption column (Plinian column) or by elutriation from extensive pyroclastic-flows (coignimbrite cloud). For large-scale eruptions, there is considerable uncertainty about which mechanism is dominant. Here we analyze in a novel way a comprehensive grainsize database for pyroclastic deposits. We demonstrate that the Mount Pinatubo climactic eruption deposits were substantially derived from coignimbrite clouds, and not only by a Plinian cloud as generally thought. Coignimbrite ash-fall deposits are much richer in breathable <10 m ash (5–25 wt%) than pure Plinian ash at most distances from the source volcano. We also show that coignimbrite ash clouds, as at Pinatubo, are expected to be more water rich than Plinian clouds, leading to removal of more HCl prior to stratospheric injection, thereby reducing their atmospheric impact.

Late Miocene-Pliocene Detachment Faulting And Pliocene-Recent Basin-And-Range Extension Inferred From Dismembered Rift Basins Of The Salt Lake Formation, Se Idaho, Susanne U. Janecke, S. M. Carney, M. E. Perkins, J. C. Evans, P. K. Link, R. Q. Oaks Jr., B. P. Nash

Geosciences Faculty Publications

Geologic mapping, basin analysis, and tephra correlations in the Clifton and Malad City East 7.5-minute quadrangles in southeastern Idaho indicate that the modern Basin-and-Range topography is only a few million years old and was superimposed on unrelated rift basins associated with the ~12 to < 4 Ma Bannock detachment system. The Miocene-Pliocene Salt Lake Formation in the greater Cache Valley area was deposited during three sub-episodes of west-southwest extension on the Bannock detachment system.

Depositional systems within the Salt Lake Formation (>10.27 ± 0.07 Ma to < 5.1-4.4 Ma) evolved in response to the changing structural configuration of rift basins in the hanging wall of the Bannock detachment system. Early alluvial fans derived from the underlying Paleozoic rocks were replaced by broad, saline/alkaline lakes during the translation phase on the detachment fault. Later, as the hanging wall broke up internally, freshwater lakes and deltas occupied newly created NE-tilted half graben, and eventually filled them with braided streams. The Bannock detachment system collapsed the Cache-Pocatello Culmination of the dormant Sevier fold-and-thrust belt, much like the Sevier Desert Detachment collapsed the Sevier Culmination and the Wasatch Fault collapsed the Wasatch Culmination.

Deposition and tilting of the Salt Lake Formation ceased in the middle to late Pliocene (< 2 >Ma?) before uplift of the Clifton Horst along a new system of Basin-and-Range normal faults. This later episode of normal faulting uplifted and exposed metamorphic rocks in …