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Articles 48781 - 48810 of 59475
Full-Text Articles in Entire DC Network
Quantitative Analysis Of The Calcareous Nannofossil Assemblages From Ciros-1, Victoria Land Basin, Antarctica, David K. Watkins
Quantitative Analysis Of The Calcareous Nannofossil Assemblages From Ciros-1, Victoria Land Basin, Antarctica, David K. Watkins
Department of Earth and Atmospheric Sciences: Faculty Publications
The lower portion of the CIROS-1 core (McMurdo Sound, Antarctica) has been cited as evidence for Late Eocene continental glaciation on Antarctica. A reassessment of this age determination is warranted in the face of mounting evidence from multiple proxies that continental glaciation was initiated by rapid ice-growth during the earliest Oligocene. Examination of calcareous nannofossil assemblages from this section confirmed very low fossil abundance, low species richness, and the presence of reworked taxa. A minimum of 37% of the total species richness in the section comprises reworked forms, including Late Cretaceous and latest Paleocene to Middle Eocene species. Quantitative analysis …
Origin Of Kaolin Deposits: Evidence From The Hisarcık (Emet-Kütahya) Deposits, Western Turkey, Ali̇ Sayin
Origin Of Kaolin Deposits: Evidence From The Hisarcık (Emet-Kütahya) Deposits, Western Turkey, Ali̇ Sayin
Turkish Journal of Earth Sciences
Kaolin deposits, situated approximately 20 km south of Hisarcık, have been formed by the alteration of dacite and dacitic tuffs related to the Miocene volcanism associated with extensional tectonics. The Hisarcık kaolin deposits occur in the Kızılcukur, Ulaşlar and Kurtdere areas. Kaolinite is the only clay mineral associated with a-quartz, K-feldspar, plagioclase, alunite, natroalunite and hematite in some kaolins, whereas, other kaolinite accompanies smectite, which represents a moderate kaolinization. Low-cristobalite is the dominant silica mineral in these kaolins. In spite of strong kaolinization, the kaolins contain a high amount of finely-disseminated a-quartz in places, resulting in low Al_2O_3 values (13.80 …
Intracontinental Quaternary Volcanism In The Niksar Pull-Apart Basin, North Anatolian Fault Zone, Turkey, Orhan Tatar, Sema Yurtmen, Haluk Temi̇z, Hali̇l Gürsoy, Fi̇kret Koçbulut, B. Levent Mesci̇, Jean Claude Guezou
Intracontinental Quaternary Volcanism In The Niksar Pull-Apart Basin, North Anatolian Fault Zone, Turkey, Orhan Tatar, Sema Yurtmen, Haluk Temi̇z, Hali̇l Gürsoy, Fi̇kret Koçbulut, B. Levent Mesci̇, Jean Claude Guezou
Turkish Journal of Earth Sciences
The Niksar Basin is sited along the eastern segment of the North Anatolian Fault Zone in Turkey. It is a young sigmoidal pull-apart basin bordered by two non-parallel master faults associated with earthquakes in 1939 and 1942. The fault geometry along the irregular ENE margin of the basin is complex where young Plio-Quaternary volcanic rocks reach the surface along pairs of steep strike-slip faults which cut the basin sediments. The volcanic rocks around the Niksar Basin have been dated by high precision K-Ar dating and the ages range between 542 ± 9 ka and 567 ± 9 ka. The lavas …
Plant Assemblage Structure On Barrier Island ‘Pimple’ Dunes At The Virginia Coast Reserve Long-Term Ecological Research Site, Brett A. Mcmillan
Plant Assemblage Structure On Barrier Island ‘Pimple’ Dunes At The Virginia Coast Reserve Long-Term Ecological Research Site, Brett A. Mcmillan
Biological Sciences Theses & Dissertations
The habitats at the VCR LTER that were the focus of the current study are the Hog Island and Parramore Island 'pimples', small, rounded dunes forming along main dune ridges of the barrier islands. There are distinct plant assemblage zones found on pimples, although most of these dunes are 10–20 m in diameter. Hypotheses of the study were that fresh water availability was a main determinant of differences between assemblages and that pimple size and location would influence diversity and assemblage structure. Research goals were (1) to describe the plant assemblages on pimples, (2) to relate edaphic and geomorphological factors …
Petrographic And Geochemical Study On Cave Pearls From Kanaan Cave (Lebanon), Fadi H. Nader
Petrographic And Geochemical Study On Cave Pearls From Kanaan Cave (Lebanon), Fadi H. Nader
International Journal of Speleology
The Kanaan cave is situated at the coastal zone, north of Beirut City (capital of Lebanon). The cave is located within the upper part of the Jurassic Kesrouane Formation (Liassic to Oxfordian) which consists mainly of micritic limestone. Twenty seven cave pearls were subjected to petrographic (conventional and scanning electron microscopy) and geochemical analyses (major/trace elements and stable isotopes). The cave pearls were found in an agitated splash-pool with low mud content. They are believed to have formed through chemical precipitation of calcite in water over-saturated with calcium. The nucleus and micritic laminae show δ18OV-PDB values of …
Seasonal Variations Of Co2 And 222Rn In A Mediterranean Sinkhole - Spring (Causse D’Aumelas, Se France), Christelle Batiot-Guilhe, Jean-Luc Seidel, Hervé Jourde, Olivier Hébrard, Vincent Bailly-Comte
Seasonal Variations Of Co2 And 222Rn In A Mediterranean Sinkhole - Spring (Causse D’Aumelas, Se France), Christelle Batiot-Guilhe, Jean-Luc Seidel, Hervé Jourde, Olivier Hébrard, Vincent Bailly-Comte
International Journal of Speleology
Carbon dioxide and 222Rn monitoring of the atmosphere of a Mediterranean sink hole - spring (SE France) during two hydrological cycles (from September 2004 to September 2006) showed seasonal variations with very high concentrations during summer (greater than 6% and 20 000 Bq/m3, respectively). Gas dynamics in caves often show seasonal variations. Meteorological parameters (barometric pressure and temperature mainly), cave geometry and fracture networks control exchanges between the cavity and outside atmosphere. Carbon dioxide and 222Rn may have different sources (atmosphere, soil, bedrock, deep gas diffusion, in situ oxidation of organic matter and, in some caves, …
The Impact Of Host Rock Geochemistry On Bacterial Community Structure In Oligotrophic Cave Environments, Hazel A. Barton, Nicholas M. Taylor, Michael P. Kreate, Austin C. Springer, Stuart A. Oehrle, Janet L. Bertog
The Impact Of Host Rock Geochemistry On Bacterial Community Structure In Oligotrophic Cave Environments, Hazel A. Barton, Nicholas M. Taylor, Michael P. Kreate, Austin C. Springer, Stuart A. Oehrle, Janet L. Bertog
International Journal of Speleology
Despite extremely starved conditions, caves contain surprisingly diverse microbial communities. Our research is geared toward understanding what ecosystems drivers are responsible for this high diversity. To asses the effect of rock fabric and mineralogy, we carried out a comparative geomicrobiology study within Carlsbad Cavern, New Mexico, USA. Samples were collected from two different geologic locations within the cave: WF1 in the Massive Member of the Capitan Formation and sF88 in the calcareous siltstones of the Yates Formation. We examined the organic content at each location using liquid chromatography mass spectroscopy and analyzed microbial community structure using molecular phylogenetic analyses. In …
Lithostratigraphy Of The Late Early Permian (Kungurian) Wandrawandian Siltstone, New South Wales: Record Of Glaciation?, S. G. Thomas, Christopher R. Fielding, Tracy D. Frank
Lithostratigraphy Of The Late Early Permian (Kungurian) Wandrawandian Siltstone, New South Wales: Record Of Glaciation?, S. G. Thomas, Christopher R. Fielding, Tracy D. Frank
Department of Earth and Atmospheric Sciences: Faculty Publications
The late Early Permian (273–271 Ma) Wandrawandian Siltstone in the southern Sydney Basin of New South Wales represents a marine highstand that can be correlated over 2000 km. A mainly fine-grained terrigenous clastic succession, the Wandrawandian Siltstone contains evidence for cold, possibly glacial conditions based on the presence of outsized clasts and glendonites, mineral pseudomorphs after ikaite, a mineral that forms in cold (0–7°C) marine sediments. A lithostratigraphic and facies analysis of the unit was conducted, based on extensive coastal outcrops and continuous drill-cores. Eight facies associations were identified: (i) siltstone; (ii) siltstone with minor interbedded sandstone; (iii) interbedded tabular …
Dinosaur Tectonics: A Structural Analysis Of Theropod Undertracks With A Reconstruction Of Theropod Walking Dynamics, Ole Graversen, Jesper Milán, David B. Loope
Dinosaur Tectonics: A Structural Analysis Of Theropod Undertracks With A Reconstruction Of Theropod Walking Dynamics, Ole Graversen, Jesper Milán, David B. Loope
Department of Earth and Atmospheric Sciences: Faculty Publications
A dinosaur trackway in the Middle Jurassic eolian Entrada Sandstone of southern Utah, U.S.A., exposes three undertracks that we have modeled as isolated tectonic regimes showing the development of fold-thrust ramp systems induced by the dinosaur’s feet. The faulted and folded sequence is comparable to crustal-scale tectonics associated with plate tectonics and foreland fold-thrust belts. A structural analysis of the dinosaur tracks shows the timing and direction of the forces exercised on the substrate by the animal’s foot during the stride. Based on the structural analysis, we establish a scenario for foot movements and weight distribution in the feet. During …
Preservation And Erosion Of Theropod Tracks In Eolian Deposits: Examples From The Middle Jurassic Entrada Sandstone, Utah, U.S.A., Jesper Milán, David B. Loope
Preservation And Erosion Of Theropod Tracks In Eolian Deposits: Examples From The Middle Jurassic Entrada Sandstone, Utah, U.S.A., Jesper Milán, David B. Loope
Department of Earth and Atmospheric Sciences: Faculty Publications
The Middle Jurassic Entrada Sandstone, exposed near the town of Escalante, southern Utah, consists of large-scale cross-bedded eolian deposits that are interbedded with horizontally laminated sand sheets and thin sets of eolian cross-strata, representing periods with a moister climate. The flat-bedded units contain numerous tracks and trackways from small to large-sized theropod dinosaurs. These tracks are today exposed in several distinct erosional states, allowing detailed studies of track and undertrack formation in eolian deposits. Tracks that originally were emplaced on sloping surfaces show, in their present-day erosional state, a morphology distinct from those originally emplaced on horizontal surfaces. Further, the …
Evaluation Of The Streambed Leakage Concept In Analytical Models Using Data From Three Pumping Tests, Sefan J. Kollet, Vitaly A. Zlotnik
Evaluation Of The Streambed Leakage Concept In Analytical Models Using Data From Three Pumping Tests, Sefan J. Kollet, Vitaly A. Zlotnik
Department of Earth and Atmospheric Sciences: Faculty Publications
Two-dimensional analytical models of pumping induced drawdown and stream depletion account for the streambed properties and stream geometry. Using data from three pumping tests performed under various hydrologic conditions, the following hypotheses were tested: (1) a partially penetrating stream at a certain distance from the pumping well can be represented by the streambed leakage term in the analytical models; (2) in the streambed leakage term, the streambed conductance coefficient λ=(WK′)/m′ accounts for the average stream width W, the streambed thickness m′, and hydraulic conductivity K′. The first hypothesis was tested by comparing results from tests under flow and no-flow stream …
Stream Network Characteristics Used To Infer The Distribution Of Fold Types In The Zagros Simply Folded Belt, Iran, Caroline M. Burberry, John W. Cosgrove, Jian Guo Liu
Stream Network Characteristics Used To Infer The Distribution Of Fold Types In The Zagros Simply Folded Belt, Iran, Caroline M. Burberry, John W. Cosgrove, Jian Guo Liu
Department of Earth and Atmospheric Sciences: Faculty Publications
Progressive deformation at a convergent margin (the Zagros Simply Folded Belt) was analysed using satellite images, digital elevation models, contour maps and artificially generated stream networks. Two end-member fold types (fault-bend folds and detachment folds) interact with streams flowing from the High Zagros Mountains into the Persian Gulf. Growing folds divert streams and create wind or water gaps in characteristic patterns which are related to the uplift histories of the two fold types. Additionally, the symmetry of minor channels reflects the inherent symmetry of the folds. The distribution of fold types is shown for the region N27°- N30°, E50°-E54° at …
Polarimetric Signatures And Microphysical Processes In Tornadic Southern And High Plains Classic Supercells, Matthew S. Van Den Broeke
Polarimetric Signatures And Microphysical Processes In Tornadic Southern And High Plains Classic Supercells, Matthew S. Van Den Broeke
Department of Earth and Atmospheric Sciences: Faculty Publications
Preliminary schematics of polarimetric signatures are developed for classic, tornadic supercells at low, mid, and upper levels for the Southern and High Plains. Schematics are developed for pre-tornado, tornado, and tornado demise times from a small collection of cases, most of which were cyclically tornadic. Characteristic signatures and patterns are identified for reflectivity factor (ZHH), differential reflectivity (ZDR), correlation coefficient (ρhv), specific differential phase (KDP), and linear depolarization ratio (LDRVH), and signatures likely related to the tornado lifecycle are discussed.
Additionally, observed changes in four polarimetric variables (ZHH, …
High-Resolution Evidence For Dynamic Transitional Geomagnetic Field Behaviour From A Miocene Reversal, Mcmurdo Sound, Ross Sea, Antarctica, Andrew P. Roberts, Anisch Bakrania, Fabio Florindo, Christopher J. Rowan, Christopher R. Fielding, Ross D. Powell
High-Resolution Evidence For Dynamic Transitional Geomagnetic Field Behaviour From A Miocene Reversal, Mcmurdo Sound, Ross Sea, Antarctica, Andrew P. Roberts, Anisch Bakrania, Fabio Florindo, Christopher J. Rowan, Christopher R. Fielding, Ross D. Powell
Department of Earth and Atmospheric Sciences: Faculty Publications
We report a high-resolution record of a Miocene polarity transition (probably the Chron C6r-C6n transition) from glacimarine sediments in McMurdo Sound, Ross Sea, Antarctica, which is the first transition record reported from high southern latitudes. The transition is recorded in two parallel cores through a 10.7 m stratigraphic thickness. The sediments are interpreted as having been deposited in a marine environment under the influence of floating ice or seaward of a glacier terminus from which a large sediment load was delivered to the drill site. The core was recovered using rotary drilling, which precludes azimuthal orientation of the core and …
Decadal Variation Of The Southwest U.S. Summer Monsoon Circulation And Rainfall In A Regional Model, Q. Steven Hu, Yongjun Zheng
Decadal Variation Of The Southwest U.S. Summer Monsoon Circulation And Rainfall In A Regional Model, Q. Steven Hu, Yongjun Zheng
Department of Earth and Atmospheric Sciences: Faculty Publications
Previous studies have identified several major causes for summer rainfall variations over the southwest United States, for example, land memory (i.e., relationships between antecedent winter season precipitation and snow cover anomalies and subsequent summer rainfall anomalies over the southwest United States; these anomalies are likely most important in the northwest United States, although antecedent anomalies in the southwest United States also may be important in determining summer rainfall variations) and sea surface temperature (SST) anomalies in the North Pacific. Atmospheric responses to these “boundary forces” interact with moisture flows from the Gulf of Mexico and from the Gulf of California …
An Improved Qc Process For Temperature In The Daily Cooperative Weather Observations, Kenneth Hubbard, Nathaniel B. Guttman, Jinsheng You, Zhirong Chen
An Improved Qc Process For Temperature In The Daily Cooperative Weather Observations, Kenneth Hubbard, Nathaniel B. Guttman, Jinsheng You, Zhirong Chen
Department of Earth and Atmospheric Sciences: Faculty Publications
TempVal is a spatial component of data quality assurance algorithms applied by the National Climatic Data Center (NCDC), and it has been used operationally for about 4 yr. A spatial regression test (SRT) approach was developed at the regional climate centers for climate data quality assurance and was found to be superior to currently used quality control (QC) procedures for the daily maximum and minimum air temperature. The performance of the spatial quality assessment procedures has been evaluated by assessing the rate with which seeded errors are identified. A complete dataset with seeded errors for the year 2003 for the …
Airborne Dust Transport To The Eastern Pacific Ocean Off Southern California: Evidence From San Clemente Island, Daniel R. Muhs, James Budahn, Marith Reheis, Jossh Beann, Gary Skipp, Eric Fisher
Airborne Dust Transport To The Eastern Pacific Ocean Off Southern California: Evidence From San Clemente Island, Daniel R. Muhs, James Budahn, Marith Reheis, Jossh Beann, Gary Skipp, Eric Fisher
United States Geological Survey: Staff Publications
Islands are natural dust traps, and San Clemente Island, California, is a good example. Soils on marine terraces cut into Miocene andesite on this island are clay-rich Vertisols or Alfisols with vertic properties. These soils are overlain by silt-rich mantles, 5–20 cm thick, that contrast sharply with the underlying clay-rich subsoils. The silt mantles have a mineralogy that is distinct from the island bedrock. Silt mantles are rich in quartz, which is rare in the island andesite. The clay fraction of the silt mantles is dominated by mica, also absent from local andesite, and contrasts with the subsoils, dominated by …
Comparison Of Local- To Regional-Scale Estimates Of Ground-Water Recharge In Minnesota, Usa, Geoffrey N. Delin, Richard W. Healy, David L. Lorenz, John R. Nimmo
Comparison Of Local- To Regional-Scale Estimates Of Ground-Water Recharge In Minnesota, Usa, Geoffrey N. Delin, Richard W. Healy, David L. Lorenz, John R. Nimmo
United States Geological Survey: Staff Publications
Regional ground-water recharge estimates for Minnesota were compared to estimates made on the basis of four local- and basin-scale methods. Three local-scale methods (unsaturated-zone water balance, water-table fluctuations (WTF) using three approaches, and age dating of ground water) yielded point estimates of recharge that represent spatial scales from about 1 to about 1000 m2. A fourth method (RORA, a basin-scale analysis of streamflow records using a recession-curve-displacement technique) yielded recharge estimates at a scale of 10–1000s of km2. The RORA basin-scale recharge estimates were regionalized to estimate recharge for the entire State of Minnesota on the …
Passive Aerobic Treatment Of Net-Alkaline, Iron-Laden Drainage From A Flooded Underground Anthracite Mine, Pennsylvania, Usa, Charles A. Cravotta Iii
Passive Aerobic Treatment Of Net-Alkaline, Iron-Laden Drainage From A Flooded Underground Anthracite Mine, Pennsylvania, Usa, Charles A. Cravotta Iii
United States Geological Survey: Staff Publications
This report evaluates the results of a continuous 4.5-day laboratory aeration experiment and the first year of passive, aerobic treatment of abandoned mine drainage (AMD) from a typical flooded underground anthracite mine in eastern Pennsylvania, USA. During 1991–2006, the AMD source, locally known as the Otto Discharge, had flows from 20 to 270 L/s (median 92 L/s) and water quality that was consistently suboxic (median 0.9 mg/L O2) and circumneutral (pH ~ 6.0; net alkalinity >10) with moderate concentrations of dissolved iron and manganese and low concentrations of dissolved aluminum (medians of 11, 2.2, and <0.2 mg/L, respectively). In 2001, the laboratory aeration experiment demonstrated rapid oxidation of ferrous iron (Fe2+) without …0.2>
Late Cenozoic Climate Changes In China’S Western Interior: A Review Of Research On Lake Qinghai And Comparison With Other Records, Steven M. Colman, Shi-Yong Yua, Zhisheng Anc, Ji Shend, A.C.G. Henderson
Late Cenozoic Climate Changes In China’S Western Interior: A Review Of Research On Lake Qinghai And Comparison With Other Records, Steven M. Colman, Shi-Yong Yua, Zhisheng Anc, Ji Shend, A.C.G. Henderson
United States Geological Survey: Staff Publications
We review Late Cenozoic climate and environment changes in the western interior of China with an emphasis on lacustrine records from Lake Qinghai. Widespread deposition of red clay in the marginal basins of the Tibetan Plateau indicates that the Asian monsoon system was initially established by ~8 Ma, when the plateau reached a threshold altitude. Subsequent strengthening of the winter monsoon, along with the establishment of the Northern Hemisphere ice sheets, reflects a long-term trend of global cooling. The few cores from the Tibetan Plateau that reach back a million years suggest that they record the mid-Pleistocene transition from glacial …
The Russell Gold Deposit, Carolina Slate Belt, North Carolina, Terry Klein, Charles Cunningham, M.A.V. Logan, Robert R. Seal Ii
The Russell Gold Deposit, Carolina Slate Belt, North Carolina, Terry Klein, Charles Cunningham, M.A.V. Logan, Robert R. Seal Ii
United States Geological Survey: Staff Publications
Gold deposits have been mined in the Carolina slate belt from the early 1800s to recent times, with most of the production from large mines in South Carolina. The Russell mine, one of the larger producers in North Carolina, is located in the central Uwharrie Mountains, and produced over 470 kg of gold. Ore grades averaged about 3.4 grams per tonne (g/t), with higher-grade zones reported. The Russell deposit is interpreted to be a sediment-hosted, gold-rich, base-metal poor, volcanogenic massive sulfide deposit in which gold was remobilized, in part, during Ordovician metamorphism. The ore was deposited syngenetically with laminated siltstones …
Source Parameters Of A M4.8 And Its Accompanying Repeating Earthquakes Off Kamaishi, Ne Japan: Implications For The Hierarchical Structure Of Asperities And Earthquake Cycle, Naoki Uchida, Toru Matsuzawa, William L. Ellsworth, Kazutoshi Imanishi, Tomomi Okada, Akira Hasegawa
Source Parameters Of A M4.8 And Its Accompanying Repeating Earthquakes Off Kamaishi, Ne Japan: Implications For The Hierarchical Structure Of Asperities And Earthquake Cycle, Naoki Uchida, Toru Matsuzawa, William L. Ellsworth, Kazutoshi Imanishi, Tomomi Okada, Akira Hasegawa
United States Geological Survey: Staff Publications
We determine the source parameters of a M4.9 ± 0.1 'characteristic earthquake’ sequence and its accompanying microearthquakes at ~50 km depth on the subduction plate boundary offshore of Kamaishi, NE Japan. The microearthquakes tend to occur more frequently in the latter half of the recurrence intervals of the M4.9 ± 0.1 events. Our results show that the microearthquakes are repeating events and they are located not only around but also within the slip area for the 2001 M4.8 event. From the hierarchical structure of slip areas and smaller stress drops for the microearthquakes compared to the M4.8 event, we infer …
San Andreas Fault Zone Mineralogy, Geochemistry, And Physical Properties From Safod Cuttings And Core, John G. Solum, Stephen Hickman, David A. Lockner, Sheryl Tembe, Jim P. Evans, Sarah D. Draper, D. C. Barton, David L. Kirschner, Judith S. Chester, Frederick M. Chester, Ben A. Van Der Pluijm, Anja M. Schleicher, Diane E. Moore, Carolyn Morrow, Kelly Bradbury, Wendy M. Calvin, Teng-Fong Wong
San Andreas Fault Zone Mineralogy, Geochemistry, And Physical Properties From Safod Cuttings And Core, John G. Solum, Stephen Hickman, David A. Lockner, Sheryl Tembe, Jim P. Evans, Sarah D. Draper, D. C. Barton, David L. Kirschner, Judith S. Chester, Frederick M. Chester, Ben A. Van Der Pluijm, Anja M. Schleicher, Diane E. Moore, Carolyn Morrow, Kelly Bradbury, Wendy M. Calvin, Teng-Fong Wong
United States Geological Survey: Staff Publications
The San Andreas Fault Observatory at Depth (SAFOD), drilled near the town of Parkfield, California (Fig. 1) (Hickmen et al., 2004) as part of the U.S. National Science Foundation's EarthScope Project (see http://www.earthscope.org), provieds a continuous set of samples through the active San Andreas Fault (SAF) zone. These samples can help address decades-old questions such as apparent weakness of the SAF (Zoback, 2000) providing the unparalleled opportunity to contrain the parameters that control the behavior of plate counding faults like the San Andreas.
Samples collected form SAFOD also complement studies of exhumed fault zones. While studies of exhumed fault zones …
Structure And Properties Of The San Andreas Fault In Central California: Recent Results From The Safod Experiment, Stephen Hickman, Mark D. Zoback, William Ellsworth, Naomi Boness, Peter Malin, Steven Roecker, Clifford Thurber
Structure And Properties Of The San Andreas Fault In Central California: Recent Results From The Safod Experiment, Stephen Hickman, Mark D. Zoback, William Ellsworth, Naomi Boness, Peter Malin, Steven Roecker, Clifford Thurber
United States Geological Survey: Staff Publications
The San Andreas Fault Observatory at Depth (SAFOD) is a 3.2-km-deep borehole observatory drilled into the San Andreas fault zone at seismogenic depths to study directly the physical and chemical processes controlling faulting and earthquake generation. SAFOD forms one component of EarthScope, a major Earth Science facility program of the U.S. National Science Foundation; the other two funded components are U.S. Array, a continental-scale seismic network, and the Plate Boundry Observatory, an extensive network of GOS receivers and strainmeters deployed acorss the western U.S. SAFOD is being conducted in collaboration with the U.S. Geological Survey and the International Continental Scientific …
Factors Influencing Ground-Water Recharge In The Eastern United States, Bernard T. Nolan, Richard W. Healy, Patrick E. Taber, Kimberlie Perkins, Kerie J. Hitt, David M. Wolock
Factors Influencing Ground-Water Recharge In The Eastern United States, Bernard T. Nolan, Richard W. Healy, Patrick E. Taber, Kimberlie Perkins, Kerie J. Hitt, David M. Wolock
United States Geological Survey: Staff Publications
Ground-water recharge estimates for selected locations in the eastern half of the United States were obtained by Darcian and chloride-tracer methods and compared using statistical analyses. Recharge estimates derived from unsaturated-zone (RUZC) and saturated-zone (RSZC) chloride mass balance methods are less variable (interquartile ranges or IQRs are 9.5 and 16.1 cm/yr, respectively) and more strongly correlated with climatic, hydrologic, land use, and sediment variables than Darcian estimates (IQR = 22.8 cm/yr). The unit-gradient Darcian estimates are a nonlinear function of moisture content and also reflect the uncertainty of pedotransfer functions used to estimate hydraulic parameters. Significance …
Stress Orientations Of Taiwan Chelungpu-Fault Drilling Project (Tcdp) Hole-A As Observed From Geophysical Logs, Hung-Yu Wu, Kuo-Fong Ma, Mark Zoback, Naomi Boness, Hisao Ito, Jih-Hao Hung, U.S. Geological Survey
Stress Orientations Of Taiwan Chelungpu-Fault Drilling Project (Tcdp) Hole-A As Observed From Geophysical Logs, Hung-Yu Wu, Kuo-Fong Ma, Mark Zoback, Naomi Boness, Hisao Ito, Jih-Hao Hung, U.S. Geological Survey
United States Geological Survey: Staff Publications
The Taiwan Chelungpu-fault Drilling Project (TCDP) drilled a 2-km-deep research borehole to investigate the structure and mechanics of the Chelungpu Fault that ruptured in the 1999 Mw 7.6 Chi-Chi earthquake. Geophysical logs of the TCDP were carried out over depths of 500–1900 m, including Dipole Sonic Imager (DSI) logs and Formation Micro Imager (FMI) logs in order to identify bedding planes, fractures and shear zones. From the continuous core obtained from the borehole, a shear zone at a depth of 1110 meters is interpreted to be the Chelungpu fault, located within the Chinshui Shale, which extends from 1013 to …
Conservation Genetics Of Snowy Plovers (Charadrius Alexandrinus) In The Western Hemisphere: Population Genetic Structure And Delineation Of Subspecies, W. Chris Funk, Thomas D. Mullins, Susan M. Haig
Conservation Genetics Of Snowy Plovers (Charadrius Alexandrinus) In The Western Hemisphere: Population Genetic Structure And Delineation Of Subspecies, W. Chris Funk, Thomas D. Mullins, Susan M. Haig
United States Geological Survey: Staff Publications
We examined the genetic structure of snowy plovers (Charadrius alexandrinus) in North America, the Caribbean, and the west coast of South America to quantify variation within and among breeding areas and to test the validity of three previously recognized subspecies. Sequences (676 bp) from domains I and II of the mitochondrial control region were analyzed for 166 snowy plovers from 20 breeding areas. Variation was also examined at 10 microsatellite loci for 144 snowy plovers from 14 breeding areas. The mtDNA and microsatellite data provided strong evidence that the Puerto Rican breeding group is genetically divergent from sites …
Sexual Selection Drives Speciation In An Amazonian Frog, Kathryn E. Boul, W. Chris Funk, Catherine R. Darst, David C. Cannatella, Michael J. Ryan
Sexual Selection Drives Speciation In An Amazonian Frog, Kathryn E. Boul, W. Chris Funk, Catherine R. Darst, David C. Cannatella, Michael J. Ryan
United States Geological Survey: Staff Publications
One proposed mechanism of speciation is divergent sexual selection, whereby divergence in female preferences and male signals results in behavioural isolation. Despite the appeal of this hypothesis, evidence for it remains inconclusive. Here, we present several lines of evidence that sexual selection is driving behavioural isolation and speciation among populations of an Amazonian frog (Physalaemus petersi). First, sexual selection has promoted divergence in male mating calls and female preferences for calls between neighbouring populations, resulting in strong behavioural isolation. Second, phylogenetic analysis indicates that populations have become fixed for alternative call types several times throughout the species’ range, …
Microsatellite Loci For Distinguishing Spotted Owls (Strix Occidentalis), Barred Owls (Strix Varia), And Their Hybrids, W. Chris Funk, Thomas D. Mullins, Eric D. Forsman, Susan M. Haig
Microsatellite Loci For Distinguishing Spotted Owls (Strix Occidentalis), Barred Owls (Strix Varia), And Their Hybrids, W. Chris Funk, Thomas D. Mullins, Eric D. Forsman, Susan M. Haig
United States Geological Survey: Staff Publications
We identified four diagnostic microsatellite loci that distinguish spotted owls (Strix occidentalis), barred owls (Strix varia), F1 hybrids and backcrosses. Thirty-four out of 52 loci tested (65.4%) successfully amplified, and four of these loci (11.8%) had allele sizes that did not overlap between spotted and barred owls. The probability of correctly identifying a backcross with these four loci is 0.875. Genotyping potential hybrid owls with these markers revealed that field identifications were often wrong. Given the difficulty of identifying hybrids in the field, these markers will be useful for hybrid identification, law enforcement and spotted …
New Insights Into Marine Migration And Winter Habitat Of Gulf Sturgeon, Randy E. Edwards, Frank M. Parauka, Kenneth J. Sulak
New Insights Into Marine Migration And Winter Habitat Of Gulf Sturgeon, Randy E. Edwards, Frank M. Parauka, Kenneth J. Sulak
United States Geological Survey: Staff Publications
Migrations and movements of Gulf sturgeon Acipenser oxyrinchus desotoi were determined using satellite pop-up archival transmitting (PAT) tags and acoustic telemetry. Adult Gulf sturgeon from four rivers in northwestern Florida were caught with gill nets and were tagged with PAT and acoustic tags in the fall of 2001 and 2002. PAT tags were programmed to release in early February 2002 and 2003 to provide information about location of late-winter marine habitats. However, only 5 of 25 provided meaningful location information. Three of the PAT-tagged fish were relocated acoustically near the PAT tag pop-up locations, one of which was in Choctawhatchee …