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Articles 26521 - 26550 of 29958
Full-Text Articles in Geology
Stability Of Paleosinks And Karstic Carbonates In The Southern Fire Clay Mining District Of Missouri, Robert Weiser Dillon
Stability Of Paleosinks And Karstic Carbonates In The Southern Fire Clay Mining District Of Missouri, Robert Weiser Dillon
Doctoral Dissertations
"The Southern Fire Clay District of Missouri was intensely mined during the late-1800’s to mid-1900’s for its valuable resource of high refractory clays deposited within Pennsylvanian sinkholes “paleosinks”. Mining operations have produced modifications in the Ozark aquifer, which in effect has possibly increased the instability of this paleokarst terrain and the potential of further environmental impacts to the land. Evidence supporting this hypothesis are: (1) A southerly shift in the regional groundwater divide relative to the topographic divide. This possibly is caused by the distribution of leaking clay pits, which suggests that the bedrock permeability or hydraulic conductivity has been …
Evolution Of Quaternary Intraplate Mafic Lavas Detailed Using Helium-3 Surface Exposure And Argon-40/Argon-39 Dating, And Elemental And Helium, Strontium, Neodymium And Lead Isotopic Signatures: Potrillo Volcanic Field, New Mexico, United States Of America And San Quintin Volcanic Field, Baja California Norte, Mexico, Wendi Joan Whitehead Williams
Open Access Theses & Dissertations
The Pleistocene Potrillo volcanic field (PVF) resides within the southern axis of the Rio Grande Rift, New Mexico, U.S.A., near the eastern extent of the Basin and Range Province. Its alkalic mafic volcanism has resulted in several hundred cones, flows and maars distributed over approximately 4,600 km2. Alignments are segregated into two halves relative to the East Robledo fault system that dissects this field. Three of the five maars have brought peridotitic and lower to upper crustal xenoliths to the surface; several older, non maar-related flows from the west half of the field host ultramafic clots. Stratigraphic relationships, 3He surface …
New Caribbean Locality For The Extinct Great White Shark Carcharodon, Clare Flemming, Donald A. Mcfarlane
New Caribbean Locality For The Extinct Great White Shark Carcharodon, Clare Flemming, Donald A. Mcfarlane
WM Keck Science Faculty Papers
Carcharodon is represented by a single upper tooth (Fig. 1) which we extracted from the eroding Pliocene limestone wall, some six meters above the floor at the northern end of Darby Sink. Much of the tooth is missing, but the remaining portion includes features diagnostic of this genus. The tooth conforms in size and morphology to Carcharodon megalodon (Agassiz, 1843), an extinct great white shark.
A Second Pre-Wisconsinan Locality For The Extinct Jamaican Rodent, Clidomys (Rodentia: Heptaxodontidae), Donald A. Mcfarlane, Joyce Lundberg, Clare Flemming, Ross D. E. Macphee, Stein-Erik Lauritzen
A Second Pre-Wisconsinan Locality For The Extinct Jamaican Rodent, Clidomys (Rodentia: Heptaxodontidae), Donald A. Mcfarlane, Joyce Lundberg, Clare Flemming, Ross D. E. Macphee, Stein-Erik Lauritzen
WM Keck Science Faculty Papers
Clidomys is the most distinctive but least well known member of the late Quaternary terrestrial mammal fauna of Jamaica. Here we report the second dated locality for this genus. The Illinoisan age we report further strengthens arguments we have made elsewhere, that Clidomys represents an early - probably pre-Wisconsinan - extinction that contrasts with the growing record of Holocene extinctions in the Antilles.
Uncertainty In Recharge From Subsidence Craters At Frenchman Flat, Nevada Test Site: Impacts Of Initial And Boundary Conditions And Media Properties, David Matthew Ely
Uncertainty In Recharge From Subsidence Craters At Frenchman Flat, Nevada Test Site: Impacts Of Initial And Boundary Conditions And Media Properties, David Matthew Ely
UNLV Theses, Dissertations, Professional Papers, and Capstones
The Nevada Test Site has over 400 subsidence craters formed by the collapse of overlying rock following underground nuclear tests. Under natural conditions, infiltration and recharge would not be considered likely due to infrequent precipitation events and extreme evapotranspiration. Crater U5a in Frenchman Flat was chosen for study because it intercepts significantly more drainage than surrounding craters. Vadose zone modeling was conducted to test the sensitivity of water movement to boundary and initial conditions. The effects of ponding depth was negligible but depth of wetting front movement was highly dependent on the lateral extent of the ponds. The model was …
Application Of The Paleomagnetic Fold Test To Determine The Relative Timing Of Sill Intrusion And Deformation In The Southwest Helena Salient, Montana, Stephen Christopher Whisner
Application Of The Paleomagnetic Fold Test To Determine The Relative Timing Of Sill Intrusion And Deformation In The Southwest Helena Salient, Montana, Stephen Christopher Whisner
Masters Theses
The Doherty Mountain fold complex is a highly folded and faulted region along the southern boundary of the Helena Salient in southwestern Montana. This region has a complex deformation history that is a key to deformation within the Helena Salient as a whole. A structural interpretation of the deformed rocks of this area was conducted using field mapping and cross section construction at 1:24,000 scale providing insight to the internal deformation processes involved. Fourteen folds and three major faults were mapped and analyzed showing the influence of the Southwest Montana Transverse Zone and late stage detachment faulting on fold orientation. …
Modelling Direct Episodic Recharge In The Western Australian Wheatbelt, F Lewis, Cooperative Research Centre For Catchment Hydrology (Australia)
Modelling Direct Episodic Recharge In The Western Australian Wheatbelt, F Lewis, Cooperative Research Centre For Catchment Hydrology (Australia)
Resource management technical reports
In agricultural regions of Western Australia, salinity is spreading. This is because the area taken up by groundwater discharge is increasing as a result of increased groundwater recharge following the replacement of native vegetation systems by annual crops and pasture species. Attempts to reduce groundwater recharge are now being made as it is hoped that this will decrease the rate of land salinisation. At several sites, average recharge rates have been estimated to be from 2% to 13% of the average annu ter hydrographs from the agricultural regions indicate that at some sites recharge does not occur as small amounts …
A Late Cambrian Positive Carbon-Isotope Excursion In The Southern Appalachians: Relation To Biostratigraphy, Sequence Stratigraphy, Environments Of Deposition, And Diagenesis, Bosiljka Glumac, Kenneth R. Walker
A Late Cambrian Positive Carbon-Isotope Excursion In The Southern Appalachians: Relation To Biostratigraphy, Sequence Stratigraphy, Environments Of Deposition, And Diagenesis, Bosiljka Glumac, Kenneth R. Walker
Geosciences: Faculty Publications
A positive carbon-isotope excursion is recorded within the Upper Cambrian sedimentary succession in the southern Appalachians that consists of the Nolichucky Shale, the Maynardville Formation, and the Copper Ridge Dolomite. The lower part of the succession contains Aphelaspis zone fauna (Early Steptoean). The extensively dolomitized and poorly fossiliferous nature of the upper part of the succession precludes any detailed biostratigraphic determinations. Correlation with similar positive carbon-isotope excursions in coeval successions elsewhere suggests that this excursion represents a perturbation in the global cycling of carbon. Comparison of excursions at different localities in North America provides a means for the application of …
Stochastic Methods For Evaluating The Potential For Wetland Rehydration In Covered-Karst Terranes, Christian David Langevin
Stochastic Methods For Evaluating The Potential For Wetland Rehydration In Covered-Karst Terranes, Christian David Langevin
USF Tampa Graduate Theses and Dissertations
Augmentation with reclaimed water is one method for rehydrating wetlands damaged by water-level declines. Augmentation with reclaimed water has been proposed for rehydrating a wetland in the covered-karst terrane of west-central Florida. There is concern because reclaimed water may contain harmful agents that could flow from the wetland 1.4 km to a municipal wellfield that withdraws 30,000 m3/day. Estimates of groundwater flow velocities were calculated from the results of detailed field studies at the wetland. Results indicate that groundwater flows downward in the surficial aquifer at rates of 0.1 to 0.2 m/day and horizontally in the Floridan aquifer …
Antelope County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 2, Sue Olafsen Lackey, Frank A. Smith, Robert F. Diffendal Jr.
Antelope County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 2, Sue Olafsen Lackey, Frank A. Smith, Robert F. Diffendal Jr.
Robert F. Diffendal, Jr., Publications
In 1930, the Conservation and Survey Division of the University of Nebraska and the United States Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in the county under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.
The map in this report shows the location of all test holes drilled in the county since 1930.
Present techniques of …
Ua66/8/3 Geogram, Wku Geography & Geology
Ua66/8/3 Geogram, Wku Geography & Geology
WKU Administration Documents
Newsletter created by and about the WKU Geography & Geology highlighting activities of faculty, students and alumni.
Holt County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 45, Sue Olafsen Lackey, Frank A. Smith, Robert F. Diffendal Jr.
Holt County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 45, Sue Olafsen Lackey, Frank A. Smith, Robert F. Diffendal Jr.
Robert F. Diffendal, Jr., Publications
In 1930, the Conservation and Survey Division of the University of Nebraska and the United States Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in Holt County, Nebraska, under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.
The map in this report shows the location of all test holes drilled in Holt County, Nebraska from 1944 to …
Onshore/ Offshore Wide-Angle Deep Seismic Profiling In Taiwan, Y. H. Yeh, R. C. Shih, C. H. Lin, C. C. Liu, H. Y. Yen, B. S. Huang, C. S. Liu, P. Z. Chen, C. S. Huang, C. J. Wu, Francis T. Wu
Onshore/ Offshore Wide-Angle Deep Seismic Profiling In Taiwan, Y. H. Yeh, R. C. Shih, C. H. Lin, C. C. Liu, H. Y. Yen, B. S. Huang, C. S. Liu, P. Z. Chen, C. S. Huang, C. J. Wu, Francis T. Wu
Earth Sciences Faculty Scholarship
In summer 1995, in collaboration with the deep multi-channel seismic profiling project around the island of Taiwan, anonshore-offshore wide-angle deep seismic profiling experiment was conducted in Taiwan. The results are expected to provide the first complete seismic images of the deep crustal structure for a better understanding of the Taiwan orogeny and subduction-collision system. The experiment consists of three profiles, one along each of the central and southern cross-island highways and another on the south-link highway of the island. For the first two lines, 35 three-component portable seismographs were deployed along each of the 116 and 135 km-long profiles onshore, …
Mapped Karst Ground-Water Basins In The Somerset 30 X 60 Minute Quadrangle, James C. Currens, Joseph A. Ray
Mapped Karst Ground-Water Basins In The Somerset 30 X 60 Minute Quadrangle, James C. Currens, Joseph A. Ray
Map and Chart--KGS
This map shows karst ground-water basins in the Somerset quadrangle, determined primarily by ground-water tracer studies. It can be used to quickly identify the ground-water basins and springs to which a site may drain. Major springs and the relative size of their catchment areas can be evaluated for potential as water supplies. The map also serves as a geographic index to literature on karst ground water in the area.
Mapped Karst Ground-Water Basins In The Campbellsville 30 X 60 Minute Quadrangle, Joseph A. Ray, James C. Currens
Mapped Karst Ground-Water Basins In The Campbellsville 30 X 60 Minute Quadrangle, Joseph A. Ray, James C. Currens
Map and Chart--KGS
This map shows karst ground-water basins in the Campbellsville quadrangle, determined primarily by ground-water tracer studies. It can be used to quickly identify the ground-water basins and springs to which a site may drain. Major springs and the relative size of their catchment areas can be evaluated for potential as water supplies. The map also serves as a geographic index to literature on karst ground water in the area.
Mapped Karst Ground-Water Basins In The Beaver Dam 30 X 60 Minute Quadrangle, Joseph A. Ray, James C. Currens
Mapped Karst Ground-Water Basins In The Beaver Dam 30 X 60 Minute Quadrangle, Joseph A. Ray, James C. Currens
Map and Chart--KGS
This map shows karst ground-water basins in the Beaver Dam quadrangle, determined primarily by ground-water tracer studies. It can be used to quickly identify the ground-water basins and springs to which a site may drain. Major springs and the relative size of their catchment areas can be evaluated for potential as water supplies. The map also serves as a geographic index to literature on karst ground water in the area.
Mapped Karst Ground-Water Basins In The Harrodsburg 30 X 60 Minute Quadrangle, James C. Currens, Joseph A. Ray
Mapped Karst Ground-Water Basins In The Harrodsburg 30 X 60 Minute Quadrangle, James C. Currens, Joseph A. Ray
Map and Chart--KGS
This map shows karst ground-water basins in the Harrodsburg quadrangle, determined primarily by ground-water tracer studies. It can be used to quickly identify the ground-water basins and springs to which a site may drain. Major springs and the relative size of their catchment areas can be evaluated for potential as water supplies. The map also serves as a geographic index to literature on karst ground water in the area.
Magma Traps And Driving Pressure: Consequences For Pluton Shape And Emplacement In An Extensional Regime, John Patrick Hogan, Jonathan D. Price, M. Charles Gilbert
Magma Traps And Driving Pressure: Consequences For Pluton Shape And Emplacement In An Extensional Regime, John Patrick Hogan, Jonathan D. Price, M. Charles Gilbert
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The level of emplacement and final form of felsic and mafic igneous rocks of the Wichita Mountains Igneous Province, southwestern Oklahoma, U.S.A. Are discussed in light of magma driving pressure, lithostatic load, and crustal magma traps. Deposition of voluminous A-type rhyolites upon an eroded gabbroic substrate formed a subhorizontal strength anisotropy that acted as a crustal magma trap for subsequent rising felsic and mafic magma. Intruded along this crustal magma trap are the A-type sheet granites (length/thickness 100:1) of the Wichita Granite Group, of which the Mount Scott Granite sheet is typical, and smaller plutons of biotite bearing Roosevelt Gabbro. …
Inclusive Chemical Characterization Of Tourmaline: Mossbauer Study Of Fe Valence And Site Occupancy, M D. Dyar, M E. Taylor, Tim Lutz, C A. Francis, C V. Guidotti, M Wise
Inclusive Chemical Characterization Of Tourmaline: Mossbauer Study Of Fe Valence And Site Occupancy, M D. Dyar, M E. Taylor, Tim Lutz, C A. Francis, C V. Guidotti, M Wise
Earth & Space Sciences Faculty Publications
We report here the results of a series of inclusive chemical characterizations, including all elements except oxygen, for a suite of 54 tourmaline samples. A combination of analytical techniques was used to analyze for major and light elements (electron microprobe), Fe3+ and Fe2+ (Mossbauer spectroscopy), H (U extraction), and B, Li, and F (ion microprobe, or SIMS). The B content of the tourmalines studied ranges from 2.86 to 3.26 B per formula unit (pfu) with 31 anions; excess boron is believed to reside in the Si site. Li ranges from 0.0 to 1.44 Li pfu and F contents are 0.0-0.91 …
Managing Granite Outcrops. Revegetation On Farms Information Kit, David Bicknell, Department Of Conservation And Land Management (Calm), The Royal Society Of Western Australia
Managing Granite Outcrops. Revegetation On Farms Information Kit, David Bicknell, Department Of Conservation And Land Management (Calm), The Royal Society Of Western Australia
Natural resources published reports
In Western Australia, granite outcrops rise from the surrounding countryside like an extensive island chain, stretching from the high rainfall south-west to the arid interior. They are extremely rich in biodiversity, which can change dramatically from outcrop to outcrop. They may contain relics of unique plant and animal populations and are very significant for nature conservation.
Granite outcrops can also be a major source of groundwater recharge within catchments, especially where the surrounding fringe and woodland vegetation has been cleared.
What is granite?
*Granite is an igneous rock consisting of large crystals of quartz, feldspar and mica or hornblende.
* …
High Resolution Seismic Reflection Interpretations Of The Hood Canal-Discovery Bay Fault Zone, Puget Sound, Washington, Brian J. Haug
High Resolution Seismic Reflection Interpretations Of The Hood Canal-Discovery Bay Fault Zone, Puget Sound, Washington, Brian J. Haug
Dissertations and Theses
The north-northeast trending Hood Canal is an elongate 75 km long, 2-5 km wide, maximum 190 m deep glacial trough that represents the western limit of Washington's Puget Sound estuary complex and eastern boundary of the Olympic Peninsula. Airgun seismic reflection data were collected in Hood Canal April 4-5, 1994 onboard the University of Washington's R. V. Thomas G. Thompson for the purpose of defining the enigmatic and relatively unstudied Hood Canal-Discovery Bay fault zone (HDF). This fault zone parallels western Hood Canal, is obscured by marine waters and thick late Quaternary glacio-marine sediments, and is defined locally by gravity …
Ichnology Of Holocene Carbonate Eolianites On San Salvador Island, Bahamas: Diversity And Significance, H. Allen Curran, Brian White
Ichnology Of Holocene Carbonate Eolianites On San Salvador Island, Bahamas: Diversity And Significance, H. Allen Curran, Brian White
Geosciences: Faculty Publications
Reprinted from: H. Allen Curran and John E. Mylroie (eds.), Proceedings of the 9th Symposium on the Geology of the Bahamas and Other Carbonate Regions: San Salvador, Bahamian Field Station
Chemical Weathering Of Volcanic Ash As A Probable Origin Of Chert In The Reid's Mistake Formation Of The Newcastle Coal Measures, Sydney Basin, Australia, Adil M. Wadia
All-Inclusive List of Electronic Theses and Dissertations
Chert is normally considered to be marine biogenic in origin. However, chert lenses and nodules in the volcanic ash horizon of the Reid's Mistake Formation at Swansea Head, Newcastle Coal Measures of the Sydney Basin appear to have formed differently. Their mode of occurrence and their close association with paper-thin clay layers within the same volcanic unit suggest that they formed as a result of chemical weathering of volcanic ash. This hypothesis is supported by the data gathered from thin section petrography and x-ray diffraction analyses. Petrographic studies indicate the precipitation of microcrystalline to cryptocrystalline quartz and the dissolution/replacement/alteration of …
An Atlas Of The Sand Hills, Ann S. Bleed, Charles A. Flowerday
An Atlas Of The Sand Hills, Ann S. Bleed, Charles A. Flowerday
Conservation and Survey Division: Faculty and Staff Publications
The Sand Hills region, approximately 19,300 square miles of sand dunes stretching 265 miles across Nebraska and into South Dakota, is the largest sand-dune area in the Western Hemisphere and is one of the largest grass-stabilized dune regions in the world.
A Preliminary Analysis Of The Fluid History Of A Normal Fault In The Keno Pit, Alligator Ridge Mining District, White Pine County, Nevada, John G. Solum
Undergraduate Honors Capstone Projects
The flow of oil along faults is only poorly understood. In many cases a fault is the only means of transportation for the oil from its area of deposition to its current location. This assumption is reasonable due to chemical fingerprinting of oil. In some cases the oil in a reservoir and the oil in a fault zone have been analyzed chemically and found to be the same. The problem is this; early in a fault's history it produces a thin layer of fine-grained material between its fault surfaces. This condition is not conductive to fluid flow. Therefore another mechanism …
Three-Dimensional Structure Of Small Strike-Slip Fault Zones In Granitic Rock: Implications For Fault-Growth Models, Kim R. Robeson
Three-Dimensional Structure Of Small Strike-Slip Fault Zones In Granitic Rock: Implications For Fault-Growth Models, Kim R. Robeson
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Three small strike-slip fault zones exposed in granitic rock in the central Sierra Nevada, California, provide field-based data to construct three-dimensional representations of each fault zone in order to compare with the geometries predicted by existing fault-growth models. All three fault zones are nearly vertical, strike -N60°E, and have left-lateral slip. The fault zones range from 60 to 140 m in length and 1 to 12 m wide. Each fault zone consists primarily of parallel to subparallel fracture and fault traces 2 to 56 m long and is separated 25 cm to 7 m by intact rock. One fault zone …
Small Strike-Slip Faults In Granitic Rock: Implications For Three-Dimensional Models, Siang Joo Lim
Small Strike-Slip Faults In Granitic Rock: Implications For Three-Dimensional Models, Siang Joo Lim
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The geometry and mineralization features of small left-lateral strike-slip faults and associated fractures in Lake Edison Granodiorite of the central Sierra Nevada, California, were examined in order to model the three-dimensional structure of strike-slip faults. These faults, which are reactivated joints, were also examined to determine fault sizes, starting joint size, and evidence for fluid flow.
The associated secondary fractures are usually found in the dilational quadrants of fault-tip regions. The longest fault-segment trace is 32.14 m; the longest joint trace is 22 m. The joint population length (l) is represented by a power-law distribution (l-n …
Quaternary Amino Acid Geochronology Of The Lahontan Basin, Nevada, And The Chewaucan Basin, Oregon, Jeffrey Bigelow
Quaternary Amino Acid Geochronology Of The Lahontan Basin, Nevada, And The Chewaucan Basin, Oregon, Jeffrey Bigelow
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Amino acid geochronology based on fossil molluscs provides a useful approach to determining the Quaternary history of Great Basin lakes. The Lahontan basin, Nevada, and the Chewaucan basin, Oregon, in the northwest corner of the Great Basin, both contained lakes during the Quaternary. The aim of this study is to improve the Quaternary geochronology in these two basins by measuring time-dependent changes in amino acids preserved in fossil molluscan shells. The abundance of D-alloisoleucine relative to Lisoleucine (All) characterizes the extent of racemization, which increases with age and Ul forms the basis of relative and correlated ages. An age-calibration curve …
Late Pleistocene Glacial Chronology Of The Western Ahklun Mountains, Southwestern Alaska, Jason P. Briner
Late Pleistocene Glacial Chronology Of The Western Ahklun Mountains, Southwestern Alaska, Jason P. Briner
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
New glacial mapping and 35 cosmogenic 36Cl surface exposure ages, the first ever reported from Alaska, constrain the extent and timing of late Pleistocene glacial fluctuations in the western Ahklun Mountains, southwestern Alaska. Morphometric and soil relative-age data characterize two main drift units deposited during the Arolik Lake and Klak Creek glaciations, named herein. During the Arolik Lake glaciation (early Wisconsin), outlet glaciers emanated from an ice cap over the central portion of the Ahklun Mountains and deposited moraines at or beyond the modern coast. These moraines have slope angles averaging about 11° and crests averaging about 35 m …
Sm-Nd Systematics As Indicators Of Displaced Plutons: A Test In The Idaho Batholith-Boulder Batholith Region, Christine J. Brand
Sm-Nd Systematics As Indicators Of Displaced Plutons: A Test In The Idaho Batholith-Boulder Batholith Region, Christine J. Brand
Masters Theses
In east-central Idaho and western Montana a 400km-long Cretaceous and Tertiary magmatic corridor extends from the Wallowa-Seven Devils terrane to the Helena Salient. Three basement provinces underlie this area: Archean basement to the east, Permo-Triassic basement to the west, and Proterozoic basement in-between. Ideally, if Cretaceous plutons were decapitated and translated eastward along thrusts over a different basement province, then the Cretaceous pluton and the in-place Tertiary pluton would show different isotopic signatures. Pluton samples from locations evenly spaced throughout the magmatic corridor were analyzed for ε0Nd, εtNd, and 147Sm/143Nd model ages …