Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

1999

Geology

Theses/Dissertations

Institution
Keyword
Publication

Articles 1 - 29 of 29

Full-Text Articles in Physical Sciences and Mathematics

Calibration, Installation Techniques, And Initial Measurements For Vertical Resistivity Probes Used In Hydrogeologic Investigations, Jeffrey Mark Groncki Dec 1999

Calibration, Installation Techniques, And Initial Measurements For Vertical Resistivity Probes Used In Hydrogeologic Investigations, Jeffrey Mark Groncki

Masters Theses

Vertical Resistivity Probes (VRPs) are being increasingly used in a variety of applications where detailed vertical resistivity information in both the vadose and saturated zones is needed. All the different possible array types and spacings must be calibrated for the effect of the 2" (outer diameter) insulating PVC cylinder on which the electrodes are mounted. Apparent resistivities must be corrected by calibration factors. Varying the installation parameters greatly influences the measured apparent resistivity because of the disturbed annulus and the composition of the backfill materials. Bentonite slurry is necessary for the installations to keep the electrodes in good contact with …


Structural And Stratigraphic Relationships Of Ortho- And Paragneisses Southwest Of Marion, North Carolina, Brendan Richardson Bream Dec 1999

Structural And Stratigraphic Relationships Of Ortho- And Paragneisses Southwest Of Marion, North Carolina, Brendan Richardson Bream

Masters Theses

This thesis examines the stratigraphic and structural relationships in the western Inner Piedmont of several orthogneisses and a paragneiss sequence. Detailed mapping was completed for an area slightly larger than one 7.5-minute quadrangle and is located southwest of Marion, North Carolina, at the northeast outcrop termination of the main Henderson Gneiss unit. From bottom to top, the stratigraphy of the study area consists of the Tallulah Falls Formation, Poor Mountain Amphibolite, and Poor Mountain Quartzite. Amphibolites and amphibole gneisses of the Tallulah Falls Formation, Poor Mountain Formation, and Dysartsville gneiss are interpreted as tholeiitic basalts related to rifting along the …


Stratigraphic Analysis Of Diamicton Units In North-Central St. Joseph County, Michigan, Andrew C. Flint Dec 1999

Stratigraphic Analysis Of Diamicton Units In North-Central St. Joseph County, Michigan, Andrew C. Flint

Masters Theses

Seven subsurface glacial diamicton units, including a paleosol, have been characterized from two borings in north-central St. Joseph County, Michigan. These units have been characterized in terms of their clay mineralogy, texture, color, and stratigraphic position. t-Tests confirm that each unit displays a significant difference in mean 7A/10A peak height ratio from all other units.

Unit 4, informally called the Gray Marker tilt has been correlated between borings in this study and to the findings of others (Gardner, 1997, Nicks, in preparation). The Newbury till described by the Indiana Geological Survey (unpublished data) may also correlate to Unit 4, raising …


Mineral Paragenesis And Ore Fluids At The Turquoise Ridge Gold Deposit, Nevada, Michiko Shigehiro Dec 1999

Mineral Paragenesis And Ore Fluids At The Turquoise Ridge Gold Deposit, Nevada, Michiko Shigehiro

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this study, mineral assemblages and related fluid inclusions at the Turquoise Ridge Carlin-type gold deposit were examined to answer the following questions: (1) What is the ore-stage mineral paragenesis? (2) At what pressures and temperatures did the deposits form? (3) What are the sources of ore fluids?

Pyrite with gold, jasperoid quartz, stibnite, orpiment, realgar, and calcite were successively deposited at Turquoise Ridge. Microthermometric data and isotopic ratios of inclusion fluids in ore-related minerals indicate entrapment of multiple generations of fluids in pre-ore, ore-, and late-ore stage minerals. Primary fluid inclusions in an ore-stage jasperoid quartz crystal have salinities …


Alteration Associated With Gold Deposition At The Getchell, Carlin-Type Gold Deposit, North-Central Nevada, Tracy Lynn Cail Dec 1999

Alteration Associated With Gold Deposition At The Getchell, Carlin-Type Gold Deposit, North-Central Nevada, Tracy Lynn Cail

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alteration at the Getchell deposit was examined to determine the effects of ore-bearing fluids on host lithologies and the relationship between K-bearing alteration minerals and Au deposition. The geochemistry of unaltered to highly altered and mineralized rocks from the Getchell deposit was quantified for 54 samples collected along 14 transects in calcareous siltstone, carbonaceous limestone, and a rhyodacitic dike. Each transect was collected along a single homogeneous bed that could be followed from visibly unaltered waste rock into high-grade ore.

Calculated elemental gains and losses record an increase in the concentrations of Au, Hg, Sb, Se, Si, Te, Tl, and …


Depositional And Diagenetic Relationships Of The Honaker-Nolichucky Formational Boundary (Middle Cambrian, Conasauga Group), Southern Appalachians, Gary Alan Ottinger Aug 1999

Depositional And Diagenetic Relationships Of The Honaker-Nolichucky Formational Boundary (Middle Cambrian, Conasauga Group), Southern Appalachians, Gary Alan Ottinger

Masters Theses

The upper Honaker and lower Nolichucky Formations (Middle Cambrian, Conasauga Group) in northeastern Tennessee comprise part of a thick pericratonic Cambro-Ordovician passive margin sequence along the eastern edge of North America. Throughout the Cambrian, the interplay of autocyclic controls, including sediment supply, tectonism and accompanying subsidence, and eustasy, resulted in various sedimentary architectures, including the Conasauga platform and intrashelf basin adjacent to the craton. To date, the Middle Cambrian westerly carbonate sections adjacent to and within the intrashelf basin (near Knoxville) have been studied in considerable detail. Particularly, these studies have proposed a third-order sequence boundary near Knoxville as well …


Sequence Stratigraphy And Paleoecology Of The Middle Cambrian Spence Shale Member Of The Langston Formation Of Northeastern Utah And Southeastern Idaho, Scott H. Wright May 1999

Sequence Stratigraphy And Paleoecology Of The Middle Cambrian Spence Shale Member Of The Langston Formation Of Northeastern Utah And Southeastern Idaho, Scott H. Wright

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Cambrian Spence Shale Member contains meter-scale, shallowing-up cycles (parasequences) and record approximately 360 ky of deposition. These meter-scale cycles are nested within transgressive systems tracts (TST) and highstand systems tracts (HST) which reflect different stages of a lower-order, higher-magnitude sea-level excursion.

Fossil assemblages are located in stratigraphic positions within the Spence Shale Member that can be predicted on the basis of sequence architecture. The cycle architecture, taphonomy, and geochemistry of the Spence parasequences confirm synthetic sections and theoretical models of meter-scale cycles developed in other studies. Delineation of meter-scale cycles, based on taphonomic and sedimentologic criteria, allows high-resolution …


Chemical And Hydrostratigraphic Characterization Of Ground Water And Surface Water Interactions In Cache Valley, Utah, J. Mike Robinson May 1999

Chemical And Hydrostratigraphic Characterization Of Ground Water And Surface Water Interactions In Cache Valley, Utah, J. Mike Robinson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A series of five east-west and two north-south hydrostratigraphic cross sections were drawn from drillers' logs of water wells within the southern half of Cache Valley, Utah. These cross-sections demonstrate that ground water flow to streams is restricted by a continuous low- II permeability layer, nearly 100-feet thick. This layer was correlated to the lake-bottom deposits of the Bonneville (30,000 -13,000 years ago) and Little Valley (140,000 - 90,000 years ago) cycles of the ancient Lake Bonneville.

The most productive aquifers in the valley, collectively termed the principal aquifer , are in the southeast corner , approximately between Smithfield and …


Cenozoic Structural And Stratigraphic Evolution Of The Southeastern Salmon Basin, East-Central Idaho, James J. Blankenau May 1999

Cenozoic Structural And Stratigraphic Evolution Of The Southeastern Salmon Basin, East-Central Idaho, James J. Blankenau

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The southeastern Salmon basin (SB) of east-central Idaho is a complex east-dipping half graben containing four unconformity-bounded sequences of Tertiary volcanic, alluvial fan, lacustrine, and fluvial deposits. From oldest to youngest these are the Challis volcanic group, sedimentary rocks of Tendoy (new name), sedimentary rocks of Sacajaweja (new name), and Quaternary-Tertiary deposits . The thick sequence of volcanic rocks was deposited in a southeast-trending paleovalley . New mapping, cross-cutting relationships, 40Ar/39Ar age determinations, and angular unconformities show that the SB has experienced at least four episodes of extension, and that it lies in the core of an …


Tertiary Stratigraphy And Structural Geology, Wellsville Mountains To Junction Hills, North-Central Utah, Kathryn M. Goessel May 1999

Tertiary Stratigraphy And Structural Geology, Wellsville Mountains To Junction Hills, North-Central Utah, Kathryn M. Goessel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study integrates detailed mapping of Tertiary deposits along the divide between the lower Bear River basin and the Cache Valley basin with several other techniques to generate a depositional model, define extension-related structures, and compile a geologic history for this part of the northeastern Basin and Range province. The study area is situated along the topographic divide between Box Elder and Cache Counties, Utah, from the Wellsville Mountains north almost to Clarkston Mountain. These ranges are cored by folded and thrusted Paleozoic rocks. They are bound on the west by normal faults of the Wasatch fault zone and on …


Geochemistry And Petrogenesis Of The Bonanza King Mafic Intrusive Complex, Trinity Terrane Ophiolite, California, Keith R. Willse May 1999

Geochemistry And Petrogenesis Of The Bonanza King Mafic Intrusive Complex, Trinity Terrane Ophiolite, California, Keith R. Willse

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Bonanza King mafic intrusive complex (MIC) (>25 km2) of the Trinity terrane ophiolite, northern California, consists of cogenetic plutonic and dike lithologies. Steep intrusive contacts exist between cumulate pyroxenite, isotropic gabbro, and peridotite country rock. Near vertical east-west trending, bimodal dikes intruded gabbro and are centered within the complex. Geochemical modeling indicates taht accumulation/fractionation of a gabbroic parental magma produced lithologic trends of cumulate pyroxenite and fractionated gabbro and dike lithologies. Similarities between all lithologies suggest cogenetic formation of all the elements of the Bonanza King MIC during the Late Silurian (431 +/- 3).

Parental magma …


The Geochronology And Geochemistry Of The Bearhead Rhyolite, Jemez Volcanic Field, New Mexico, Leigh Justet May 1999

The Geochronology And Geochemistry Of The Bearhead Rhyolite, Jemez Volcanic Field, New Mexico, Leigh Justet

UNLV Theses, Dissertations, Professional Papers, and Capstones

Around 82% of mapped Bearhead Rhyolite (Main Cluster) and Peralta Tuff appears to have been derived from a relatively long-lived (~680 ka), large, shallow (Earth's surface) magma chamber that did not produce a caldera-forming eruption. Although volatile contents were great enough (~ wt.% H2O), no large-scale explosive eruptions occurred because magma may have been tectonically vented. The lack of systematic chemical variation within the Main Cluster with time during this ~680 ka interval may imply that erupted magmas were physically separated from each other by fault-formed cupolas in the roof of the magma chamber. These results are significant …


The Origin Of Brucite In Hydrothermally Altered Limestone Near Devil Peak, Nevada, Rhonda L. Knupp May 1999

The Origin Of Brucite In Hydrothermally Altered Limestone Near Devil Peak, Nevada, Rhonda L. Knupp

UNLV Theses, Dissertations, Professional Papers, and Capstones

Open-space brucite was identified in veins crosscutting hydrothermally altered limestone near the Devil Peak rhyolite plug in southern Nevada. The brucite occurs with serpentine, calcite, chalcedony, hydromagnesite, dolomite, and clinochlore.

Brucite usually forms as a replacement mineral, but textural evidence indicates that the brucite at Devil Peak precipitated in open space. The presence of chalcedony in veins indicates the temperature of the hydrothermal fluid was <180oC during and after mineral deposition. Thermodynamic modeling shows this temperature is too low for replacement brucite to form, thus the low temperature of alteration may be a factor in this unusual occurrence of …


Effects Of Organic Matter And Iron-Rich Clay On Mobility Of Trace Metals From Flue Dust Contaminated Soil, Scott Ephraim Lewis Apr 1999

Effects Of Organic Matter And Iron-Rich Clay On Mobility Of Trace Metals From Flue Dust Contaminated Soil, Scott Ephraim Lewis

OES Theses and Dissertations

The enhanced leaching of trace metals through soil becomes a concern for human health if dissolved trace metals reach groundwater and migrate into a public water system. A serial batch extraction procedure was implemented to determine the effects of Vitagrow © organic matter and Fe-Rich TM clay on the mobility of trace metals (Zn, Pb, and Cd) from a flue dust treated (0, 600, 1200, and 2400 μgig Zn) Appling soil.

The addition of an organic matter (OM) amendment to the Appling soil enhanced Pb mobility and reduced soluble Zn and Cd. In general, average solution concentrations of trace metals …


Major- And Minor-Element Analysis Of Apollo 14 Volcanic Green Glasses B, And Petrogenic Modeling Of Apollo 14 Green Glasses A And B, Vera Assis Fernandes Jan 1999

Major- And Minor-Element Analysis Of Apollo 14 Volcanic Green Glasses B, And Petrogenic Modeling Of Apollo 14 Green Glasses A And B, Vera Assis Fernandes

Geology Theses and Dissertations

The lunar picritic volcanic glasses have been identified as being quenched samples of primary magmas extruded onto the lunar surface via fire-fountains. The study of the composition of these glasses is of extreme importance for the understanding of the Moon's mantle composition and petrogenetic processes.
Based on their chemical signature (low-Ti and high Mg#) and physical characteristics, the lunar picritic glasses are believed to represent primary magmas. Experimental data suggest that these melts formed at 360-500 km depth (18-25 kbar) in the lunar mantle, and were transported onto the lunar surface through a "channel" network (McKenzie, 1985b) that isolated these …


The Geology Of The Liberty-Orrington-Passagassawakeag/Fredericton Trough Terrane Boundary In The Bucksport-Orland Area, Coastal Maine, Heather A. Short Jan 1999

The Geology Of The Liberty-Orrington-Passagassawakeag/Fredericton Trough Terrane Boundary In The Bucksport-Orland Area, Coastal Maine, Heather A. Short

Geology Theses and Dissertations

The Liberty-Orrington fault separates two tectonic terranes of widely different lithologies and metamorphic grades within the Coastal Lithotectonic Belt of Maine. While the juxtaposition of the sillimanite-bearing Passagassawakeag gneiss and the chlorite grade Bucksport Formation (turbidites) requires a fault between them, field evidence for, and an understanding of, the nature of the fault has hitherto been lacking. Although the Liberty-Orrington fault has previously been interpreted as a thrust, strike-slip, and/or normal fault, the most recent debate has been centered around two models of Acadian amalgamation involving thrusting of the Passagassawakeag terrane from the southeast vs. thrusting from beneath central Maine …


Bridger Formation Sandstones Used As An Indication Of Tectonics In The Green River Basin And Western Wyoming, Lisa S. Novins Jan 1999

Bridger Formation Sandstones Used As An Indication Of Tectonics In The Green River Basin And Western Wyoming, Lisa S. Novins

Honors Papers

Sandstone from the Eocene Bridger Formation of southwestern Wyoming can be used as a tool to constrain the timing and order of controversial tectonic events in the region. The key tectonic element in this region is the Wind River Range. Sandstones in the Bridger were derived from two source areas to the north, one being the basement rocks from the Wind River Range and the other volcanic rocks from the Absaroka Volcanic field (AVF). The abundance of volcanic grains increases upsection in the Bridger indicating that more volcanic material was carried through the Wind River Range. This evidence supports the …


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 Jan 1999

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 …


In-Situ Measurement Of Denitrification In The Elk Valley Aquifer, Allen Schlag Jan 1999

In-Situ Measurement Of Denitrification In The Elk Valley Aquifer, Allen Schlag

Theses and Dissertations

Groundwater serves more than half of North Dakota's population as a drinking water source. Nitrate (NO₃¯) is a common groundwater contaminant associated with fertilizers, septic systems and livestock waste in shallow unconfined aquifers. As a suspected carcinogen and cause of potentially lethal methemoglobinemia in infants, the natural attenuation of NO₃¯ by denitrification can be an important process in keeping groundwater as a reliable source of clean drinking water for North Dakota. Organic carbon is often considered the most important electron donor for the chemical reduction of NO₃¯ into harmless nitrogen gas. However, several studies have shown that inorganic electron donors …


Fine-Scale Strata Formation In Biologically And Physically Dominated Estuarine Systems Within The Lower Chesapeake And York River Subestuary, Timothy M. Dellapenna Jan 1999

Fine-Scale Strata Formation In Biologically And Physically Dominated Estuarine Systems Within The Lower Chesapeake And York River Subestuary, Timothy M. Dellapenna

Dissertations, Theses, and Masters Projects

To investigate the relationship between biological and physical mixing in forming strata, the lower mainstem of Chesapeake Bay has been contrasted with the York River Subestuary. By using radioisotope profiles from sediment cores, comparisons are made in terms of depth and rate of sediment mixing, deposition and accretion. Within the lower Chesapeake Bay two sites were selected as biologically dominated, both are located within the bay stem plains and are characterized by muddy sand and an abundance of large, deep-dwelling organisms. X-radiographs indicate complete biological reworking of sediments. 210Pb profiles reveal low sediment accretion rates within the mainstem sites ( …


Stratigraphy And Sedimentology Of The Pipestone Canyon Formation, North Central Washington, James Jenner Peterson Jan 1999

Stratigraphy And Sedimentology Of The Pipestone Canyon Formation, North Central Washington, James Jenner Peterson

WWU Graduate School Collection

Since Mesozoic time, the western margin of North America has grown through the addition of tectonic terranes, transported atop the subducting paleo-Pacific oceanic plate. The “Baja British Columbia” terrane model postulates accretion of the Insular superterrane at the latitude of southern Mexico and subsequent, margin-parallel translation north to juxtaposition with the western portion of the Intermontane superterrane. After amalgamation, the composite block continued north to its current location. The timing of the proposed translation has not bear well constrained. In the study area, the Okanogan Range batholith of the Intermontane superterrane’s Quesnellia terrane is juxtaposed with the sedimentary and volcanic …


A Fluid Inclusion And Structural Analysis Of The West Chance Vein System, Sunshine Mine, Kellogg, Idaho, David S. (David Scott) Boyer Jan 1999

A Fluid Inclusion And Structural Analysis Of The West Chance Vein System, Sunshine Mine, Kellogg, Idaho, David S. (David Scott) Boyer

WWU Graduate School Collection

The Sunshine mine, near Kellogg ID, is a mesothermal Ag-Pb vein deposit in the Coeur d’Alene mining district. Proterozoic siliciclastic rocks of the Ravalli Group, Belt Supergroup, host the ore bodies. The recently discovered West Chance ore body has been under development for the past five years. This tabular ore body strikes west and dips steeply to the south, has 300m (~1000 ft) strike length and extends approximately 914m (~3000 ft) down dip. Ore is located where the WNW-striking Chance fault changes to a predominately west-striking structure. This study consists of a fluid inclusion and structural analysis of the West …


Seismic Characterization Of The Northern Puget Lowland, Washington, Lori K. (Lori Kelly) Roberts Jan 1999

Seismic Characterization Of The Northern Puget Lowland, Washington, Lori K. (Lori Kelly) Roberts

WWU Graduate School Collection

Records show that thousands of earthquakes have occurred in the northern Puget Lowland since 1969. At least fifteen of these events have been greater than magnitude 4, and one (Deming mag. 5.2, 1990) was the second largest recorded shallow crustal event in Washington for the last hundred years. Despite the evidence that suggests that the potential for great earthquakes capable of severe damage in the northern Puget Lowland is very real, the seismicity in the area is poorly understood. This is in part due to the wide scattering and apparently random assortment of recorded events. This thesis attempts to create …


Structure And Metamorphism Of The Talc Creek Area, Harrison Lake B.C., Minda L. Troost Jan 1999

Structure And Metamorphism Of The Talc Creek Area, Harrison Lake B.C., Minda L. Troost

WWU Graduate School Collection

The Slollicum and Cogburn terranes, metamorphosed country rock within the southern Coast Plutonic Complex, are juxtaposed along a thrust fault together with large slabs of ultramafic rock. The structure and metamorphism along and near this fault are the focus of this study.

Three periods of deformation (D1-D3) affected the study area. D1 structures consist of penetrative foliation and lineations that are attributed to thrust stacking of the Slollicum and Cogburn terranes. Foliation, which parallels the fault contact, dips to the northeast at moderate to steep angles. Lineations have mainly down-dip orientations. D2 structures record …


Hydrogeology And Paleohydrology In The Williamson River Basin, Klamath County, Oregon, Jeffrey Scott Conaway Jan 1999

Hydrogeology And Paleohydrology In The Williamson River Basin, Klamath County, Oregon, Jeffrey Scott Conaway

Dissertations and Theses

Stress on the water resources of the Williamson River basin has led to their regulation to protect important habitat. Quantification of this resource is required for accurate regulation. A portion of this study is a hydrogeologic reconnaissance that suggests directions for future work. Measured discharge and deuterium isotope data from points above and below the Williamson River canyon indicate that the river receives 99% of its discharge from ground water during periods of low flow. The principle aquifer of the southern Klamath Marsh is a fractured basalt, while continental sediments that are up to 200 m thick provide high artesian …


Sediment Dispersal And Sequence Development Along A Tectonically Active Margin: Late Quaternary Evolution Of The Ganges-Brahmaputra River Delta, Steven Lee Goodbred Jr. Jan 1999

Sediment Dispersal And Sequence Development Along A Tectonically Active Margin: Late Quaternary Evolution Of The Ganges-Brahmaputra River Delta, Steven Lee Goodbred Jr.

Dissertations, Theses, and Masters Projects

Situated in the Bengal Basin, the Ganges-Brahmaputra river delta comprises one of the largest fluviodeltaic systems in the world, comprising ∼ 100,000 km2 of floodplain and delta plain and a 40,000 km2 subaqueous delta on the shelf. Sediment load of the Ganges-Brahmaputra river is 109 t/yr, and seasonal flooding may inundate >70% of the delta during large events. Active tectonic processes have resulted in both uplift and subsidence in this structurally complex region. These general characteristics suggest that the Ganges-Brahmaputra delta represents a heretofore undescribed delta end-member, forming along a high-yield, high-energy, tectonically active margin. to investigate this view, stratigraphic, …


Olivine Petrofabric Analysis From The Leka Ophiolite Complex, Sarah J. Titus Jan 1999

Olivine Petrofabric Analysis From The Leka Ophiolite Complex, Sarah J. Titus

Honors Papers

Peridotites, gabbros and basaltic volcanic rocks on the island of Leka, Norway in the western Scandinavian Caledonides compose a nearly complete ophiolite sequence. I examined samples from the harzburgite to dunite transition within the ultramafic tectonites of the Leka Ophiolite Complex. This rock sequence probably corresponds to the petrologic Moho, which is the true base of the oceanic crust and lies below the seismic Moho. I used universal stage techniques to determine the crystallographic preferred orientations (CPO) of olivine grains in both dunites from the base of the oceanic crust and residual harzburgites in the uppermost upper mantle. Olivine CPOs …


Description And Taphonomy Of A Turtle Assemblage (Chelonia: Trionychidae) In The Sentinel Butte Formation (Paleocene), Billings County, North Dakota, Glenn B. Kays Jan 1999

Description And Taphonomy Of A Turtle Assemblage (Chelonia: Trionychidae) In The Sentinel Butte Formation (Paleocene), Billings County, North Dakota, Glenn B. Kays

Theses and Dissertations

Soft-shelled turtle fossils (Family: Trionychidae) are common in Late Mesozoic and Early Cenozoic freshwater terrestrial deposits throughout western North America. Taxonomy of the Trionychidae is confusing for two reasons: 1) there are differences of opinion as to which characters are important in defining the lower systematic groups; 2) trionychid fossil material is often incomplete and fragmentary and has been used as the basis for numerous taxonomic descriptions.

The Ash Coulee Quarry is a fossil turtle assemblage located within the lower portion of the Sentinel Butte Formation (Paleocene) in Billings County, North Dakota. This quarry has produced at least 40 individual …


Stability Of Paleosinks And Karstic Carbonates In The Southern Fire Clay Mining District Of Missouri, Robert Weiser Dillon Jan 1999

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 …