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Articles 27181 - 27210 of 29717
Full-Text Articles in Physical Sciences and Mathematics
Stratigraphy And Textural Analyses Of A Beach Ridge Complex, Cape Henry, Virginia, Daniel Leland Oyler
Stratigraphy And Textural Analyses Of A Beach Ridge Complex, Cape Henry, Virginia, Daniel Leland Oyler
OES Theses and Dissertations
Eight lithological units, documented from the analyses of 26 boreholes, comprise five laterally extensive horizons in the subsurface of Cape Henry, Virginia. Interpretations of the environments of deposition for those units are based upon textural and compositional features, fossils, thickness and distribution of strata, and previous reports about late Tertiary and Quaternary deposits in nearby areas. The incised, Pliocene Chowan River Formation (Unit H) underlies Pleistocene Units F and G which are concentrated in a buried river valley beneath Cape Henry. Estuarine Units D and E resulted from a marine transgression of the study area during the early Holocene. The …
Tectonic Implications Of Late Tertiary Strata Exposed Along The Piankatank River, Eastern Virginia, Daniel Stephen Lane
Tectonic Implications Of Late Tertiary Strata Exposed Along The Piankatank River, Eastern Virginia, Daniel Stephen Lane
OES Theses and Dissertations
Biostratigraphic analysis of Late Miocene and Pliocene strata along the Piankatank River in eastern Virginia exposes a juxtaposition of the Eastover and Yorktown Formations. This structure is situated on a NE trending alignment of geological, geomorphic, and geophysical features which run from southern Virginia to northern Delaware. Tectonic jointing in isolated sandstone bodies and fracture controlled drainage patterns provide further evidence of post-middle Pliocene tectonism in the region. The lateral spacing of this structure from the Stafford and Brandywine fault zones and other linear features on the Coastal Plain strongly implies that a structural similarity exists between the Piankatank structure …
Amatitlan, An Actively Resurging Cauldron 10 Km South Of Guatemala City, Richard L. Wunderman, William I. Rose
Amatitlan, An Actively Resurging Cauldron 10 Km South Of Guatemala City, Richard L. Wunderman, William I. Rose
Department of Geological and Mining Engineering and Sciences Publications
A 14×16 km diameter collapse caldera has been recognized 10 km south of Guatemala City, Guatemala. The caldera is north of the presently active volcano Pacaya and west of Agua, a large stratovolcano. The caldera was not previously recognized because its eastern and western margins coincide with faults that outline the Guatemala City graben and because the northern margin of the caldera is buried by pyroclastic rocks. The existence of the northern caldera margin is now established by gravity data and a variety of geological observations including circumferential faults, hot springs, well-log data, and lithological changes in sedimentary rocks. A …
Late Quaternary Vegetational History At Cupola Pond, Ozark National Scenic Riverways, Southeastern Missouri, Everett Newman Smith Jr.
Late Quaternary Vegetational History At Cupola Pond, Ozark National Scenic Riverways, Southeastern Missouri, Everett Newman Smith Jr.
Masters Theses
A 12 meter core of lacustrine sediments from Cupola Pond, Ripley County, Missouri, Provides the first continuous record in the Ozark Plateaus Region of ecologic changes from full-glacial time to the present. From 17,100 to 15,350 yr B.P., forest communities were dominated by jack and/or red pine (northern Diploxylon Pinus) and spruce (Picea). A late-glacial, transitional forest of oak (Quercus), ash (Fraxinus), pine and spruce characterized the upland vegetation that occurred during a period of climatic amelioration between 15,350 and 12,300 yr B.P. The early Holocene period from 12,300 to 9,100 yr B.P. …
Inventory Of Irrigation Water Use Box Butte County, Nebraska 1981, Dennis R. Lawton, Larry L. Teahon
Inventory Of Irrigation Water Use Box Butte County, Nebraska 1981, Dennis R. Lawton, Larry L. Teahon
Conservation and Survey Division
No abstract provided.
Geologische Untersuchungen Zur Frühen Metallurgie In Nw-Anatolien, G.A. Wagner, E. Pernicka, T.C. Seeliger, Ö. Öztunali, I. Baranyi, F. Begemann, S. Schmitt Strecker
Geologische Untersuchungen Zur Frühen Metallurgie In Nw-Anatolien, G.A. Wagner, E. Pernicka, T.C. Seeliger, Ö. Öztunali, I. Baranyi, F. Begemann, S. Schmitt Strecker
Bulletin of the Mineral Research and Exploration
No abstract provided.
Geology, Sedimentary Environments Of The Vicinity Of Emet And Its Borate Areas, Aydoğan Akbulut, Aykan Aygün, Ali Dündar
Geology, Sedimentary Environments Of The Vicinity Of Emet And Its Borate Areas, Aydoğan Akbulut, Aykan Aygün, Ali Dündar
Bulletin of the Mineral Research and Exploration
No abstract provided.
Barbados Ridge; Inner Trench Slope Sedimentation, William J. Cleary, H. Allen Curran, Paul A. Thayer
Barbados Ridge; Inner Trench Slope Sedimentation, William J. Cleary, H. Allen Curran, Paul A. Thayer
Geosciences: Faculty Publications
Quaternary sediments of this inner trench slope are chiefly foraminiferal-pteropod-nanno oozes that have been reworked and/or emplaced by gravity currents. These oozes are mixed with volcanogenic sediments and minor amounts of material derived from the insular shelf. Reworking occurs on topographic highs where fines are winnowed out and mass wasting and gravity currents are initiated; these processes ultimately result in the leveling of irregular floors of deeper, intervening slope basins. Petrographic analyses of graded intervals from the basin floors and slopes reveal the sands to be mixtures of planktic foraminifers (35%), pteropods (10%), and fresh, angular volcanic detritus (10-90%). On …
Palynology And Age Of The Alvord Creek Formation, Steens Mountain, Southeastern Oregon, Stephen F. Barnett
Palynology And Age Of The Alvord Creek Formation, Steens Mountain, Southeastern Oregon, Stephen F. Barnett
Loma Linda University Electronic Theses, Dissertations & Projects
The age of the Alvord Creek Formation of Steens Formation, southeastern Oregon, has been a center of controversy since Axelrod's 1944 paleobotanical assignment of a Lower Pliocene age to the tuffaceous leaf-bearing shales. This date varies from earlier determinations by Chaney and MacGinitie that the flora was Mascall (Upper Miocene) equivalent. However, it is more sharply contradicted by the report of a Middle Miocene (Barstovian) fauna in the apparently overlying Steens Basalt and by a 21.3 m.y. radiometric date obtained on a basalt flow 61 meters above the leaf-bearing beds.
Palynomorphs recovered from three exposures of the leaf-bearing beds show …
Groundwater Levels In Nebraska, 1983, Martin S. Johnson, Darryll T. Pederson
Groundwater Levels In Nebraska, 1983, Martin S. Johnson, Darryll T. Pederson
Conservation and Survey Division
No abstract provided.
Geology, Alteration And Mineralization Of A Silicic Volcanic Center, Glass Buttes, Oregon, Michael James Johnson
Geology, Alteration And Mineralization Of A Silicic Volcanic Center, Glass Buttes, Oregon, Michael James Johnson
Dissertations and Theses
Glass Buttes, a Pliocene silicic volcanic complex within the High Lava Plains province of Oregon, was erupted approximately 5.0 to 5.8 million years ago. Geologic mapping revealed that the eastern portion of the complex is underlain by rhyolitic glass domes, flows and rare pyroclastic flows. Basalt flows are interlayered with and onlap the silicic glass. Younger basalt flows, erupted from local vents, overlie silicic glass and onlapping basalts.
The eastern end of Glass Buttes is hydrothermally altered at the surface; a weak geothermal anomaly coincides with the altered areas. Alteration, localized by northwest trending normal faults, occurs primarily as opalite …
Structure And Petrology Of Tertiary Volcanic Rocks In Parts Of Toms Cabin Spring And Lucin Nw Quadrangles (Box Elder Co.), Utah, Bruce Edward Scarbrough
Structure And Petrology Of Tertiary Volcanic Rocks In Parts Of Toms Cabin Spring And Lucin Nw Quadrangles (Box Elder Co.), Utah, Bruce Edward Scarbrough
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
A series of late Tertiary rhyolitic and dacitic flows, domes, and minor pyroclastic rocks form an elongate volanic mass along the northwestern Utah-northeastern Nevada border. The structure of the flow banding and the linear arrangement of vents indicate that the mass represents a multi-sourced extrusive complex which erupted through many fissure-type conduits. A 39 km2 area at the southern end of the mass was studied in detail in order to gain a better understanding of the eruptive nature and history of these Tertiary volcanic rocks. Age dating reveals that volcanism in the study area was episodic, and covered a …
Evaluation Of Low-Temperature Geothermal Potential In North-Central Box Elder County, Utah, Matthew C. Davis
Evaluation Of Low-Temperature Geothermal Potential In North-Central Box Elder County, Utah, Matthew C. Davis
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The purpose of this study was to continue the assessment of low-temperature geothermal resources in Utah started by the Utah Geological and Mineral Survey. The area of interest with in this report is north-central Box Elder County, Utah. Exploration techniques used included chemical analyses of water from wells and springs, temperature surveys, and temperature-depth measurements in unused wells within the study area. The highest water temperatures (31, 30, and 29°C) recorded in this research were located in three separate geographic regions, suggesting that no single warm water occurrence dominates the study area.
Total dissolved solid (TDS) concentrations ranged from 294 …
Petrology Of The Middle Jurassic Twin Creek Limestone, Lincoln And Sublette Counties, Southwestern Wyoming, David R. Raubvogel
Petrology Of The Middle Jurassic Twin Creek Limestone, Lincoln And Sublette Counties, Southwestern Wyoming, David R. Raubvogel
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Twin Creek Limestone of Middle Jurassic age was studied in the Tunp, Salt River, and Wyoming Ranges in southwestern Wyoming. Modern carbonate environments and their ancient analogs were compared with information obtained from field study and petrographic analysis of samples of the Twin Creek Limestone in order to delineate environments of deposition, paleogeography, and diagenetic history.
Six major lithofacies were recognized: (1) carbonate mudstone; (2) carbonate mudstone breccia; (3) fossiliferous wackestone; (4) packstone-grainstone; (5) terrigenous mudstone; and (6) sandstone. These lithofacies were deposited in a variety of environments, including outer shelf platforms (carbonate mudstone and fossiliferous wackestone), oolitic sand …
Petrology Of The Middle Cambrian Ute Formation, North-Central Utah And Southeastern Idaho, Edward James Deputy
Petrology Of The Middle Cambrian Ute Formation, North-Central Utah And Southeastern Idaho, Edward James Deputy
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Middle Cambrian Ute Formation was studied in the Bear River Range and the Wellsville Mountains of north-central Utah and southeastern Idaho. The depositional textures and sedimentary structures found within the rocks were compared with similar modern sediments and ancient rocks to determine depositional environments, paleogeography, and diagenetic alterations.
The rocks of the Ute Formation were divided into five basic types. These five rock types were formed within four identifiable lithofacies: 1) elastic marine shelf; 2) carbonate marine shelf; 3) agitated shoal; and 4) quiet-water shoal.
The sequence of elastic and carbonate sediments is believed to have been deposited in …
A Bacteriological And Chemical Analysis Of Nonpoint Source Pollution In A Karst Aquifer Bowling Green, Kentucky, Wayne Green
A Bacteriological And Chemical Analysis Of Nonpoint Source Pollution In A Karst Aquifer Bowling Green, Kentucky, Wayne Green
Masters Theses & Specialist Projects
Monthly water samples collected from four sites in the Lost River Groundwater Basin, a shallow karst aquifer in the Bowling Green-Warren County area of Kentucky, represented samples from sites receiving conduit and diffuse flow. All sites were severely contaminated with bacteria, and on some occasions the surface water criteria for some heavy metals were exceeded.
Of the total 334 bacterial colonies identified 92.1% were verified as Escherichia coli by the API20E system. Acinetobacter calcoaceticus var. anitratum accounted for 2.10% of colonies; Citrobacter freundii for 0.30% Klebsiella pneumoniae for 0.90%; Klebsiella oxytoca, 0.90%; Citrobacter amalonaticus 0.30%; Enterobacter cloacae, 1.20%; …
Enteric Contamination Of An Urban Karstified Carbonate Aquifer: The Double Springs Drainage Basin, Bowling Green, Kentucky, Geary Schindel
Enteric Contamination Of An Urban Karstified Carbonate Aquifer: The Double Springs Drainage Basin, Bowling Green, Kentucky, Geary Schindel
Masters Theses & Specialist Projects
Biological and chemical analysis of water samples, collected from surface and subsurface streams was preformed to determine the quantity and biologic sources of enteric contamination in the Double Springs Groundwater Basin, an urban karstified carbonate aquifer under Bowling Green, Kentucky. Major flow paths, drainage basin boundaries and geologic/hydrologic relationships were identified for the basin. Analysis of biologic contaminates using fecal coliform /fecal streptococcus counts and ratios were conducted for baseflow and storm events and related to the Double Springs hydrographs. Analysis was also conducted to determine the source of sulfides responsible for the growth of sulfur fixing bacteria in the …
Structural Geology Of The Northern Snowcrest Range, Beaverhead And Madison Counties, Montana, Mark Kenneth Sheedlo
Structural Geology Of The Northern Snowcrest Range, Beaverhead And Madison Counties, Montana, Mark Kenneth Sheedlo
Masters Theses
The Snowcrest Range was uplifted in Late Cretaceous and Early Tertiary time as a consequence of thrusting in Precambrian basement and Phanerozoic cover rocks.
The Snowcrest-Greenhorn thrust system is associated with largescale overturned, eastward verging folds. Mean orientation of the thrust system is N.40°E., 35°N.W.. The trend of the thrust system and associated transverse faults appear to be controlled by earlier structures. Mesoscopic and microscopic analyses indicate that metamorphic basement rocks accommodated congressional strain largely by brittle faulting and cataclastic shearing. Kinematic indicators suggest that local stresses were directed east-southeastward.
Northeast-trending Neogene faults along the western flank of the range …
Ichnology Of Pleistocene Carbonates On San Salvador, Bahamas, H. Allen Curran
Ichnology Of Pleistocene Carbonates On San Salvador, Bahamas, H. Allen Curran
Geosciences: Faculty Publications
ABSTRACT-Trace fossils, well preserved and in full relief, are present in Pleistocene calcarenites of subtidal, beach, and dune facies on San Salvador, Bahamas. Most prominent are irregular boxworks of Ophiomorpha sp. that occur in current-bedded, medium to coarse skeletal calcarenites in association with fossil coral reefs in the subtidal facies. Ophiomorpha sp. also occurs in beds deposited in a tidal delta environment. Found with Ophiomorpha sp., often in abundance, are vertical burrow tubes assigned to Skolithos linearis. Trace fossils are absent from beds of the lower beach facies, but upper beach facies beds (backshore zone) contain distinctive Y-shaped crab …
Tracemaking Activities Of Crabs And Their Environmental Significance: The Ichnogenus Psilonichnus, Robert W. Frey, H. Allen Curran, S. George Pemberton
Tracemaking Activities Of Crabs And Their Environmental Significance: The Ichnogenus Psilonichnus, Robert W. Frey, H. Allen Curran, S. George Pemberton
Geosciences: Faculty Publications
Modem crabs are common inhabitants of shallow subtidal, intertidal, and supratidal environments, and many crabs are capable of producing traces that can be preserved in the rock record. The first crabs, Early Jurassic in age, probably were not fossorial. By Cretaceous time, however, diverse endobenthic lineages were established. Many representatives of these lineages undoubtedly produced domiciles that are preserved in shallow marine to quasimarine sediments and that should be useful in characterizing the depositional environment of the sediments. Nonetheless, most such dwelling structures have been studied little and remain essentially unnamed.
The ichnogenus Psilonichnus Fiirsich is amenable to the taxonomic …
A Resource Survey Of The Coastal Lands From Vlaming Head To Tantabiddi Well, West Cape Range Region, P A. Hesp, J G. Morrissey
A Resource Survey Of The Coastal Lands From Vlaming Head To Tantabiddi Well, West Cape Range Region, P A. Hesp, J G. Morrissey
Resource management technical reports
The report comprise four parts; a brief review of the area's climate, discussion of the geomorphology of the major landform units, an assessment of the potential erosion hazards of the surveyed landforms, and recommendations for development.
The Effect Of Viscosity On Impact Cratering And Possible Application To The Icy Satellites Of Saturn And Jupiter, Jonathan H. Fink, Donald Gault, Ronald Greeley
The Effect Of Viscosity On Impact Cratering And Possible Application To The Icy Satellites Of Saturn And Jupiter, Jonathan H. Fink, Donald Gault, Ronald Greeley
Geology Faculty Publications and Presentations
Impact experiments in Newtonian fluids with a range of viscosities of 10-3 to 60 Pa s demonstrate that transient prater volume and shape (depth-to-diameter: ratio) depend on target viscosity as well as on gravity. Volume is reduced, and depth-to-diameter ratio is increased for cratering events in which viscosity plays a dominant role. In addition to being affected by target kinematic viscosity, viscous scaling is most strongly influenced by projectile diameter, less strongly by projectile velocity, and least strongly by gravity. In a Planetary context, viscols effects can occur for craters formed by small or slow moving impacting bodies, low …
Interpretation Of The Chemical And Physical Time-Series Retrieved From Sentik Glacier, Ladakh Himalaya, India, Paul Andrew Mayewski, N. Ahmad, Gordon Smith, M. Pourchet
Interpretation Of The Chemical And Physical Time-Series Retrieved From Sentik Glacier, Ladakh Himalaya, India, Paul Andrew Mayewski, N. Ahmad, Gordon Smith, M. Pourchet
Earth Science Faculty Scholarship
Spectral analysis of time series of a c. 17 ± 0.3 year core, calibrated for total β activity recovered from Sentik Glacier (4908 m) Ladakh, Himalaya, yields several recognizable periodicities including sub-annual, annual, and multi-annual. The time-series, include both chemical data (chloride, sodium, reactive iron, reactive silicate, reactive phosphate, ammonium, δD, δ(18O) and pH) and physical data (density, debris and ice-band locations, and microparticles in size grades 0.50 to 12.70 μm). Source areas for chemical species investigated and general air-mass circulation defined from chemical and physical time-series are discussed to demonstrate the potential of such studies in the …
Fission Track Dating Of Detrital Zircons From The Scotland Sandstones, Barbados, West Indies, Suzanne Louise Baldwin
Fission Track Dating Of Detrital Zircons From The Scotland Sandstones, Barbados, West Indies, Suzanne Louise Baldwin
Geology Theses and Dissertations
Results of fission track dating of detrital zircons from the Scotland sandstones, Barbados, yield a mixture of ages with several strong groupings from 20-80 Ma, 200-350 Ma, and greater than 500 Ma. Metamict grains were assumed to fall into the greater than 500 Ma population.
The youngest population indicates that the Scotland beds, previously dated by paleontologic methods as Eocene, may actually be as young as late Oligocene. These ages better constrain the timing of deposition for these sediments and support the proposal that the late middle Eocene - early Oligocene Oceanic Fm has overthrust the Scotland beds. This population …
The Influence Of Oceanic Transform Boundaries On The Generation And Evolution Of Oceanic Lithosphere, David G. Gallo
The Influence Of Oceanic Transform Boundaries On The Generation And Evolution Of Oceanic Lithosphere, David G. Gallo
Geology Theses and Dissertations
The first-order geologic and morphologic relationships at, along and proximal to ridge-transform-ridge plate boundaries are used to construct an empirical and speculative tectonic model. The geometry of a ridge-transform intersection necessitates the juxtaposition of relatively cold, thick lithosphere against the truncated end of an accreting plate boundary. The cold face of lithosphere cools the adjacent wedge of asthenosphere rising beneath the axis of accretion and restricts the amount of partial melting thus attenuating the amount of basaltic melt segregated from the asthenosphere per unit time. The manifestation of this cold edge effect is a thinner oceanic crust. At depth, upper …
Structural Analysis Of Deformed Carboniferous Strata, Mispec Beach, Southern New Brunswick, Lauren Magin Bradley
Structural Analysis Of Deformed Carboniferous Strata, Mispec Beach, Southern New Brunswick, Lauren Magin Bradley
Geology Theses and Dissertations
Mispec Beach, New Brunswick is a coastal exposure of deformed Carboniferous sedimentary rocks. Late Paleozoic deformation in the region is thought to have occured in a restraining bend in the Cobiquid - Chedabucto fault.
Within this exposure, two main generations of deformation are recognized. The first deformation is associated with slaty cleavage development, pebble elongation, and the formation of quartz veins. The second generation structure is a moderately developed crenulation cleavage. The diversity of structures present at this outcrop allows for a qualitative determination of the principal axes of stress and strain associated with the first generation structures.
The Tectonic Evolution Of The Eastern Yukon Tanana Upland, Alaska, Grant W. Cushing
The Tectonic Evolution Of The Eastern Yukon Tanana Upland, Alaska, Grant W. Cushing
Geology Theses and Dissertations
Field, structural, and isotopic studies in the southeastern Eagle Quadrangle reveal a complex Mesozoic history involving major metamorphism, fold development, thrusting, and igneous intrusion. These events may be related to the accretion of a terrane, possibly Stikine, to the North American continental margin.
40Ar/39Ar incremental heating experiments on metamorphic minerals from amphibolite facies rocks reveal Late Triassic to Middle Jurassic plateau ages interpreted as the age of major metamorphism. Large scale northeast trending folds within these rocks formed after the major metamorphism and before the intrusion of an undeformed, unmetamorphosed cross-cutting dike in Middle Jurassic. These folds probably developed in …
The Geology Of Ophiolitic And Adjoining Rocks Of Chagnon Mountain, Southern Quebec, Janet M. Harris
The Geology Of Ophiolitic And Adjoining Rocks Of Chagnon Mountain, Southern Quebec, Janet M. Harris
Geology Theses and Dissertations
Chagnon Mountain is located near the southern end of the Baie Verte-Brompton Line in the Eastern Townships of southern Quebec. The lithologic units in the area of study, from west to east and going up structure, are: gabbro, quartz-diorite, diabase, volcanics, the St. Daniel Formation and the Peasley Pond Conglomerate of the Glenbrooke Group. All these rocks have been metamorphosed to the greenschist facies. Contacts between the plutonic rocks are irregular and gradational indicating only one parent magma. Diabase dikes are present in the diabase unit and in the volcanics indicating the dikes acted as feeders to the volcanics. Geochemical …
Some Aspects Of Deformation Fabrics Along The Highland/Lowland Boundary, Northwest Adirondacks, New York State, Peter C. Hall
Some Aspects Of Deformation Fabrics Along The Highland/Lowland Boundary, Northwest Adirondacks, New York State, Peter C. Hall
Geology Theses and Dissertations
The Geology of the Whippoorwill Corners Area, NW Adirondacks, NYS
In the northwestern Adirondack Mountains of New York State lies a 110 km long, 0-5 km wide topographic and lithologic boundary which divides the Adirondack Highlands from the Northwest Lowlands. Structurally this boundary is apparently a highly strained zone of intensely foliated and lineated rocks. Within the zone mineral grains are highly recrystallized and of fine grain size with respect to rocks outside the zone, quartz becomes undulose, and mineral assemblages frequently exhibit retrograde characteristics. Despite the apparent high strain no demonstrable offset may be seen across the zone. Furthermore, …
Chatham Fault Zone, Old Chatham-East Chatham, New York: Mesostructures And Microstructures: Their Spatial And Age Relationships, Jorge Mora M.
Chatham Fault Zone, Old Chatham-East Chatham, New York: Mesostructures And Microstructures: Their Spatial And Age Relationships, Jorge Mora M.
Geology Theses and Dissertations
Detailed studies in rocks of Mettawee (Late Precambrian? to Early Cambrian) and Walloomsac (Middle Ordovician) slates between Old Chatham and East Chatham, New York, have shown that these rocks were intensely deformed during the Taconic orogeny and a later deformation event(?). Two generations of structures are clearly recognized in the area. The first generation (G1) includes tight west-verging folds whose axial plane foliation is the regional foliation slaty cleavage (S1). These structures are considered synchronous with the regional metamorphism of the Taconic orogeny and correlative with those structures belonging to the D2 deformation event proposed by Ratcliffe (1979) and Rowley …