Physical Sciences and Mathematics Commons^™

Structural Analysis Across The Northeast Boundary Of The Taconic Allochthon, West-Central Vermont, Thomas E. Hoak

Geology Theses and Dissertations

The Taconic Allochthon is an elongate belt of Cambro-Ordovician, argillaceous sediments with lesser occurrences of calcareous and siliceous lithologies. These lithologically distinctive strata lie tectonically juxtaposed over a coeval medial-Ordovician carbonate shelf sequence. This geometry resulted from an arc-continent collision in which a westward-migrating arc (Ammonoosuc Volcanics) collided with an eastern North America passive margin and the accumulated accretionary prism of the forearc region was thrust onto the passive continental margin.
The present thesis examined the structural sequence at the north end of the Allochthon and the continuity of this sequence into the adjacent Parautochthonous Shelf strata. Structurally, the study …

Granitic Pegmatites In The Southeastern Adirondacks: Their Use As Indicators Of Temperature, Pressure, And Fluid Conditions During A Late Stage Of The Grenville Orogeny, John P. Mihalich

Geology Theses and Dissertations

Granitic pegmatites associated with the Grenville orogeny intrude a mid-Proterozoic, upper amphibolite to near granulite facies terrane in the southeastern Adirondack Mountains of New York State. The inferred anatectic, fluid-saturated, and minimum melt characteristics of the pegmatites suggest that they can be used as analogs of the "granite" or "haplogranite" system, and as indicators of crustal temperature, pressure, and fluid conditions during a late stage of the Grenville orogeny. Bulk chemical compositions of seven simple, undeformed pegmatites in the southeastern Adirondacks indicate that they are generally depleted in silica and sodium, and enriched in potassium, relative to experimental data on …

Geology, Geochemistry, And Geochronology Of The Lems Ridge Olistostrome, Klamath Mountains, California, Matthias Ohr

Geology Theses and Dissertations

The Lems Ridge olistostrome (LRO), located within the western Jurassic belt of the Klamath Mountains geologic province, is a melange unit showing a distinct block-in-matrix fabric. The conformable relationship to both an igneous basement and the overlying flysch of the Late Jurassic Galice Formation points to a sedimentary origin. The lack of pervasive deformation and the internal stratification also support a predominantly olistostromal origin of the LRO. The matrix of the LRO consists of pebbly mudstone which interfingers with tuffaceous greenstone and tuff-breccias. Subordinate beds of chert, argillite, and sandstone are also present. The matrix contains abundant ophiolitic clasts, fragments …

The Providence Island Formation In The Northern Appalachian Region - A Lower-Lower Middle Ordovician Analogue To Recent Arid-Semiarid Tidal-Flat Carbonates Of The Persian Gulf Trucial Coast, Mauricio Roma Hernandez

Geology Theses and Dissertations

The Providence Island Formation of Early-early Middle Ordovician age occurs in the Champlain Valley and adjacent areas in eastern New York, western Vermont, and southern Quebec. The unit forms part of a carbonate shelf sequence which occupied the eastern margin of the North American continent from Newfoundland to Alabama, and its lithology is representative of the dolostone lithofacies that characterizes the uppermost Beekmantown Group in this region.
This is the first study documenting depositional environments, diagenesis, and stratigraphic correlations of the Providence Island Formation. This formation consists, in decreasing abundance, of dolostones, limestones, shales, and dedolostones. The dominantly fine grain …

Geology Of The Northern Baie Verte Peninsula, Newfoundland, Canada, Pamela J. Stella

Geology Theses and Dissertations

On the eastern portion of the Burlington Peninsula of northwest central Newfoundland, Canada, there are two different age groups of volcanic and volcaniclastic rocks. There have been arguments in the past as to whether or not these two groups are actually only one group (Cape St. John Group) but with progressive intensity of deformation and metamorphism from south to north. Other workers have divided the rocks into two distinct groups, the Grand Cove Group and the Cape St. John Group based on their differences in deformation style and metamorphic grade. This study ignored previous divisions of the rocks into one …

Structural Investigations On Experimentally And Naturally Produced Slickensides, Thomas Michael Will

Geology Theses and Dissertations

This work has involved an experimental approach and a study of naturally produced slickensides.
The experiments, carried out on a pyrophyllitic rock, have been performed in order to define some extrinsic parameters that control surface and microstructural features. Normal stress, speed (i.e. strain rate), and amount of slip and total displacement were related to measureable surface features, such as length, and spacing between the developing ridges and grooves. Special attention was paid to a newly recognized type of slickenside lineation (Means, 1986). This lineation produced experimentally cannot be explained in terms of the traditional asperity ploughing or dissolution/precipitation models. It …

Identification Of Endmembers For Magma Mixing In Little Sitkin Volcano, Alaska, Douglas A. Wolf

Geology Theses and Dissertations

Little Sitkin island is an Aleutian calc-alkalic volcanic center that has erupted a suite of lavas ranging from andesite through rhyodacite. Whole-rock chemistry of these lavas indicates contrasting evolutionary processes; major-oxide silica variation diagrams exhibit linear trends that are suggestive of magma-mixing while trace-element trends are largely controlled by accessory-phase fractionation.
Plagioclase, the dominant phenocryst phase in all lavas, commonly occurs in two distinct populations with markedly different compositions and textures. Both normal and reverse zonation is noted in the plagioclase and clinopyroxene of several samples. In addition, clinopyroxene is found as rims on orthopyroxene grains and as cores with …

Spatial And Temporal Analysis Of 1200 Landslides In A 900km2 Area, Middle Rocky Mountains, Wyoming, U.S.A., James P. Mccalpin

James P. McCalpin

An inventory of approximately 1200 landslides in a 900 km2 area in the Salt River Range, western Wyoming, U.S.A., reveals regional and temporal controls on the landsliding process. Sliding is strongly controlled by eight weak formations in the 21 stratigraphic units of Cambrian through Cretaceous age. Morphologic dating of slides suggests that rockslides, slump-flows, and debris flows have occurred rather uniformly in time within the Holocene. In contrast, earthflows seem to be triggered more by cool/wet climatic epicycles in the last 5,000 years.

Field Trip Roadlog For The Bear River Landslide Complex, James P. Mccalpin

James P. McCalpin

The Bear River Landslide Complex occurs where the unconsolidated sediments of the Bear River Delta have been incised to a depth of 350 to 490 feet (106-150 m) north of Preston, Idaho. The slides are the result of the high pore pressure in confined aquifers in the deltaic sediments. High but variable volumes of groundwater flow and the laterally discontinuous nature of the deltaic sediments result in the varied types of earth movements found within the Landslide Complex. Landslide activity occurs during years of above average precipitation, and has been exacerbated by increased recharge from reservoirs and irrigation canals constructed …

Recommended Setback Distances From Active Normal Faults, James P. Mccalpin

James P. McCalpin

The geometry of near-surface ground breakage was analyzed from 40 trenches across Quaternary normal faults to help define reasonable setback distances. From each of the trench logs (28 on the Wasatch Fault, 11 on other Great Basin faults) eight parameters characteristic of surface rupture style were measured. Parameters included: 1) position of the main fault in relation to scarp morphology. 2) dip of the main fault. 3) number of faults on the upthrown block, 4) width of the upthrown block fault zone. 5) number of faults in the downthrown block. 6) width of the downthrown deformation zone, 7) ratio of …

The Bear River Landslide Complex, Preston, Idaho: Geologic Considerations And Historical Perspectives, James P. Mccalpin

James P. McCalpin

The Bear River Landslide Complex is a series of earth movements in northern Cache Valley, north of Preston, Idaho. The landslides occur in unconsolidated sediments of the Pleistocene Bear River Delta which formed where the river entered Lakes Bonneville and Provo. The Lake Bonneville delta deposits are up to 490 feet (150 m) thick and consist of a lower alluvial coarse sand and gravel unit, a middle delta front fine sand and silt unit, and an upper pro-delta clay up to 50 feet (15 m) thick. The interbedded character of the fine sands, silts, and clays, together with abrupt lateral …

Biostratigraphic Zonation Of Late Paleozoic Depositional Sequences, Charles A. Ross, June R. P. Ross

Geology Faculty Publications

Correlation of more than seventy third-order depositional sequences in Carboniferous and Permian strata uses assemblage zones of warm water benthic and nektonic shelf faunas. These include calcareous foraminifers, bryozoans, conodonts, and ammonoids and represent tropical, subtropical, and warm temperate water faunas from carbonate shelves and adjacent cratonic basins.

After the Early Carboniferous faunal zonation was highly provincial and worldwide correlations of depositional sequences are based on interpretations of evolutionary lineages and depositional patterns in each province and in identifying times of limited dispersals between provinces.

Associated with these faunal zones there were times of expanded or reduced faunal diversities and …

Genesis Of Marine Terrace Soils, Barbados, West Indies: Evidence From Mineralogy And Geochemistry, Daniel R. Muhs, Russell C. Crittenden, John N. Rosholt, Charles A. Bush, Kathleen C. Stewart

United States Geological Survey: Staff Publications

Well-developed, clay-rich soils dominated by interstratified kaolinite-smectite are found on the uplifted coral reef terraces on the island of Barbados. The reef limestone is unlikely to have been the soil parent material however, because it is 98 per cent CaCO, and geomorphic evidence argues against the 20 m of reef solution required to produce the soils by this process. The mineralogy of the sand, silt, and clay fractions of the soils, and trace element geochemistry, suggest that aeolian materials carried on the trade winds from Africa, volcanic ash from the island of St. Vincent, and quartz from Tertiary bedrock on …

Isotope Content And Temperature Of Precipitation In Southern Nevada, August 1983-August 1986, W. K. Milne, Larry Benson, P. W. Mckinley

United States Geological Survey: Publications

From August 1983 through August 1986, 429 precipitation samples of 112 precipitation events were collected at 12 stations in southern Nevada. Some of these samples were analyzed for oxygen-18, deuterium, and tritium. The results of these analyses as well as the air temperature and the precipitation measured at the collection sites are tabulated in this report. The sampling program provides a data base for future interpretive studies on the timing and origin of ground-water recharge in the Yucca Mountain region, of southern Nevada.

The stable-isotope composition of precipitation is the result of fractionation processes that occur in the atmosphere. Isotopic …

Botanical Evidence For Holocene Movement Of Rock Streams In Arkansas, S. Marie Lookingbill, Malcolm K. Cleaveland, Margaret J. Guccione

Journal of the Arkansas Academy of Science

Botanical studies of rock streams on the western half of Rich Mountain and on the north slope of Mt. Magazine in Arkansas question the common presumption that such streams require periglacial conditions to form, and are now inactive relict features in this area. Trees along the margins of the streams examined show abundant evidence of trauma resulting from Late Holocene movement, in the form of bent and tilted stems. Cross sections of trees demonstrate marked eccentric growth associated with tilting and cambial trauma associated with corrasion by rocks. That this damage is not the result of excessive snow loading is …

Trace Fossils In Carbonate Upper Beach Rocks And Eolianites: Recognition Of The Backshore To Dune Transition, H. Allen Curran, Brian White

Geosciences: Faculty Publications

Reprinted from: H. Allen Curran (ed.), Proceedings of the Third Symposium on the Geology of the Bahamas: Fort Lauderdale, Florida, CCFL Bahamian Field Station

Duer Ranch, Morrill County, Nebraska: Contrast Between Cenozoic Fluvial And Eolian Deposition, James B. Swinehart, R. F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The Duer Ranch locality contains some of the finest and most easily accessible examples of different styles of alluvial cuts and fills in the Cenozoic rocks of Nebraska. It offers a unique area in which to examine the geometries and alluvial fills of several Miocene and Pliocene age paleovalleys and paleo-gullies. Good exposures of eolian volcaniclastic siltstones and a regionally important volcanic ash of the Oligocene age Brule Formation are also present at the Duer Ranch locality. In addition, Quaternary ephemeral stream development and deposits can be studied.

Location and Accessibility

Significance of the Locality

Locality Information

Measured Sections [I-IV] …

Paleohydrology Of Some Ogallala (Neogene) Streams In The Southern Panhandle Of Nebraska, R. G. Goodwin, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Stratification and estimated paleoflow conditions for valley-fill deposits suggest that Ogallala Group streams in western Nebraska were similar to modern streams of south-central Alberta.

Ogallala stratification includes medium-scale (0.5 to 2.0 m thick) trough crossbedded sand and gravel, tabular indistinctly horizontally bedded and imbricated gravel, and horizontally bedded sand and pebbly sand. Valley fills are 15 to 55 m thick and 800 to 1800 m wide at the top. Some are in bedrock-floored channels resembling the “inner channels” of Shepherd and Schumm (1974).

Gradients for three well exposed paleovalley floors range from 0.0014 to 0.0020 (m/m) after tectonic correction. This …

Textural And Lithologic Differences Of Cretaceous, Tertiary, And Quaternary Gravels Of South Arkansas, Lesli Wood

Journal of the Arkansas Academy of Science

Stream gravels have been derived from the Ouachita Mountains since at least Cretaceous times. Past studies have assigned ages to gravel deposits in the basins of the Saline and Little Missouri Rivers on the basis of altitude above local floodplains. This study examines the lithologies and textures of seven gravel outcrops ranging in age from Cretaceous to Quaternary to determine whether any patterns of variation based on assigned ages, variable sources, or precise depositional setting can be discerned. No variation patterns could be found for size distributions of sand-sized and larger fractions. However, the amount of silt-clay matrix decreases through …

Late Paleozoic Sea Levels And Depositional Sequences, Charles A. Ross, June R. P. Ross

Geology Faculty Publications

Cyclic sea level charts for the Lower Carboniferous (Mississippian), Middle and Upper Carboniferous (Pennsylvanian), and Permian show considerable variability in the duration and magnitude of third-order depositional sequences, and also in the position of general sea level as represented by second-order sea level. Transgressive and highstand system tracts are numerous on the cratonic shelves of the late Paleozoic continents. Shelf margin wedges are less well represented except at times of general lower sea levels. Most low stand wedges and all low stand fan systems are structurally deformed and make up many of the accretionary wedges and displaced terranes that lie …

Geology And Mining Industry Of The Tintic District, Utah, George Warren Tower, Jr., George Otis Smith

All U.S. Government Documents (Utah Regional Depository)

The field work upon which this report is based was begun in July, 1897, and continued without interruption until December of the same year. The area studied is approximated 15 miles square and contains 234 square miles. The topographic maps, which are two in number, were prepared under the direction of Mr. R. U. Goode, Mr. S. S. Gannett doing the triangulation and Messrs. Marshall and Griswold the topography in the fall of 1896 and summer of 1897. The mapping is done on two scales; the larger area, approximately 15 miles square, is mapped on a scale of 1:62,500. This …

Coral Reef To Eolianite Transition In The Pleistocene Rocks Of Great Inagua, Bahamas, Brian White, H. Allen Curran

Geosciences: Faculty Publications

Great Inagua Island, the southernmost of the chain of Bahamian islands, lies approximately 100 km northeast of the eastern tip of Cuba. This paper reports the results of reconnaissance geologic field work conducted on Great Inagua Island in January, 1985, and of more detailed observations made in January, 1986, near Matthew Town, between South West Point and Devil's Point.

Coarsening Of Fine-Scale Exsolution Lamellae, John B. Brady

Geosciences: Faculty Publications

Diffusional exchange between the wedge-shaped terminations of fine-scale, coherent exsolution lamellae and the large flat sides of adjacent like lamellae is proposed as the principal mechanism for the coarsening of lamellar exsolution textures in silicate minerals. Following the methods of Gibbs (1906), a formula is derived for the chemical potential gradients due to interfacial energy effects that drive the proposed diffusion and coarsening....

Low-Energy Bedload Transport By Combined Wave And Current Flow On A Southern Mid-Atlantic Bight Shoreface, Malcolm O. Green

Dissertations, Theses, and Masters Projects

The control of the mean flow, wind-wave energy and wind-wave asymmetry on low-energy bedload transport magnitude, direction and divergence on a wave-dominated shoreface was investigated. The objective was to develop a mechanistic basis for postulated fairweather replenishment of the beach sediment prism by sediments derived from offshore. Fairweather currents were measured at 17.5-m and 22-m depth. Periods of competent flow were identified using a combined-flow boundary-layer model. Madsen and Grant's (1976) combined-flow bedload-transport model was used to calculate sediment fluxes after modification of the expression for instantaneous transport rate to include a threshold criterion; this was necessary since sediment is …

Depositional And Diagenetic History Of The Middle Ordovician Carbonates Of The Shenandoah Valley, Northern Virginia, Lynn Ellen Weyenberg

OES Theses and Dissertations

An examination of the Middle Ordovician carbonates in northwest Virginia has revealed a particularly sensitive record of deposition and subsidence. Two-hundred acetate peels from six measured stratigraphic sections in Shenandoah County, Virginia were examined to interpret the depositional and diagenetic history. Two major lithofacies have been recognized within the New Market Limestone and three have been recognized in the Lincolnshire Formation. These five lithofacies represent an overall transgressive sequence. This transgression was not uniform but paused several times to allow carbonate deposition to reach sea-level. These shoaling events suggest a slowly subsiding basin in this region. The carbonate rocks within …

The Hydrogeology Of Nags Head Woods, Dare County, North Carolina, Janet Salyer Emry

OES Theses and Dissertations

Nags Head Woods, a coastal maritime forest located on a barrier island in eastern North Carolina, stabilizes a back-barrier dune system bordering a tidal marsh. The purpose of this study is to provide basic information about the groundwater geology in Nags Head Woods and to predict the effects upon water levels due to municipal pumping of Fresh Pond, a large lake near the center of the island.

Clean, fine-to-medium sands dominate the top of the surficial (water table) aquifer, underlain by silty fine-to-coarse sands at -4 m elevation. A silty clay bed of very low permeability is present at -12 …

An Inventory And Condition Survey Of Rangelands In The Carnarvon Basin, Western Australia, A L. Payne, G F. Spencer, P J. Curry

Technical Bulletins

The inventory and condition survey of rangelands in the Carnarvon Basin, undertaken by the Department of Agriculture and Food, Western Australia (DAFWA) between 1980 and 1982, describes and maps the natural resources of the region’s pastoral leasehold land. This survey report provides a baseline record of the existence and condition of the natural area’s resources, to assist with the planning and implementation of land management practices. The report identified and described the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animals. It also assessed the impact of pastoralism and made land management recommendations. The area surveyed covers …

Quantification Of Net Shore-Drift Rates In Puget Sound And The Strait Of Juan De Fuca, Washington, R. Scott Wallace

WWU Graduate School Collection

Quantitative analysis of net shore-drift has been carried out at twenty-six sites in Puget Sound and the Strait of Juan de Fuca, Washington, U.S.A. Three methods were used to obtain net shore-drift rates: (1) field measurement of sediment accumulation at drift obstructions; (2) extrapolation of spit growth using aerial photographs and historical maps; and (3) evaluation of maintenance-dredging volumes at navigation channels.

The study area was divided into four regions based on physiography, and the effect of wind patterns on the area. The largest volumes of sediment were transported in the west-central region, along the southern coast of the Strait …

Occurrence And Distribution Of Shell In The Vicinity Of Parker's Rock, Pocomoke Sound, Carl H. Hobbs Iii

Reports

This is a summary report on the investigation of the occurrence and distribution of shell in the vicinity of Parker's Rock. Pocomoke Sound. The investigation was performed by the Virginia Institute of Marine Science at the request and with the financial support of the Virginia Marine Resources Commission. The site (Figure 1) was selected. primarily. at the direction of the Commission. acting on the recommendation of its shell-dredging contractor and. secondarily. with supporting reconnaissance seismic data from VIMS.

A Seismic Refraction Study Of A Portion Of The Northeastern Margin Of The Tualatin Valley, Oregon, David John Nazy

Dissertations and Theses

The Tualatin Valley is a well defined elliptical basin centered at Hillsboro, with a major axis trending roughly N65°W. The valley is bordered on the northeast by the Tualatin Mountains (Portland Hills) which are a faulted, northwest-trending asymmetrical anticline. Topographic and geophysical evidence have defined the Portland Hills fault, which occurs along the northeast side of the Tualatin Mountains. The possibility that a fault or fault zone occurs along the southwest side of the Tualatin Mountains was investigated in this study.