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Geology

Theses/Dissertations

2002

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Articles 1 - 30 of 38

Full-Text Articles in Physical Sciences and Mathematics

Seasonal Biogeochemistry And Mineral Cycling Of The Middle Rio Grande Alluvial Aquifer, New Mexico, David Stewart Vinson Dec 2002

Seasonal Biogeochemistry And Mineral Cycling Of The Middle Rio Grande Alluvial Aquifer, New Mexico, David Stewart Vinson

Earth and Planetary Sciences ETDs

The Rio Grande in central New Mexico flows through a semi-arid, historically aggrading Quaternary rift basin. Flow regulation measures include dams, irrigation diversions, levees, and bank stabilization. These have caused severe impairment including incision, lowered water tables, and less overbank flooding; disrupted groundwater - surface water interactions; altered seasonal organic carbon dynamics; and declining native biota. Previously dynamic flowpaths in the shallow alluvial aquifer (hyporheic corridor) have become are less reversible due to parallel drain ditches with lower beds than the river. These ditches impose relatively static hydraulic gradients on the alluvial aquifer that force water to flow from the …


Integrated Geophysical Examination Of A Former Refinery Site, Carson City, Michigan, Kennedy Opiyo Mwanda Dec 2002

Integrated Geophysical Examination Of A Former Refinery Site, Carson City, Michigan, Kennedy Opiyo Mwanda

Masters Theses

Integrated geophysical surveys, including electromagnetic (EM-31), magnetic, dc resistivity, and ground penetrating radar (GPR) methods and soil borings were used to investigate part of a former refinery site in Carson City, Michigan, which has more than a 50-year history of hydrocarbon contamination.

Although not readily evident on the magnetic anomaly maps, the EM-31 conductivity map clearly revealed many sections of buried pipes of various lengths and orientations. Also evident on the EM maps are extensive near surface conductivity anomalies. Soil borings in zones of anomalous conductivities to the west suggest the presence of shallow clays with pooled hydrocarbons at depths …


Inorganic And Organic Chemistry Of The Former Lakeside Refinery In Kalamazoo, Michigan, Kurt W. Carlson Dec 2002

Inorganic And Organic Chemistry Of The Former Lakeside Refinery In Kalamazoo, Michigan, Kurt W. Carlson

Masters Theses

The focus of this investigation of the Lakeside Refinery site is the inorganic geochemistry because previous investigations concerned organics and heavy metals. Because little nitrate is in native groundwater, high dissolved ammonia immediately downgradient from a petroleum body suggests the source is the petroleum and/or associated byproducts. Iron reduction is most prominent immediately upgradient from the known and measurable petroleum while manganese reduction occurs mostly downgradient. Sulfate reduction occurs mostly towards the southern portion of the light petroleum LNAPL. Based on concentrations of nitrate, manganese, iron and sulfate along a groundwater flow path, there appears to be a sequential use …


Martian Xenon Components In Basaltic Shergottite Meteorites, Katherine Delene Ocker Stone Dec 2002

Martian Xenon Components In Basaltic Shergottite Meteorites, Katherine Delene Ocker Stone

Doctoral Dissertations

Analyses of Chassigny, Nakhla, and ALH84001 reveal, in addition to a Xe component from the martian atmosphere, a second component loosely attributed to the martian "interior." This appears to be a mixture of solar- and fission- (244Pu) derived xenon components. The proportions are consistent in each meteorite but vary from meteorite to meteorite. The working hypothesis is that this variation reflects different contributions of solar (mantle-derived) and fission (crustal-derived) xenon to each parent melt.

This study focused on mineral separates from two basaltic shergottites, Shergotty and EETA79001 Lithology-B (EETA), chosen to reflect, as far as possible, the extremes …


Microbial Community Structure In Hydrocarbon Impacted Sediment Associated With Anomalous Geophysical Signatures, Joseph W. Duris Dec 2002

Microbial Community Structure In Hydrocarbon Impacted Sediment Associated With Anomalous Geophysical Signatures, Joseph W. Duris

Masters Theses

The Crystal Refinery is a former refinery site in Carson City Michigan that has had historic releases of refined and unrefined crude oil dating back to the late 1940's. The contamination of soil with light non-aqueous phase liquids (LNAPL) has had a dynamic impact on the subsurface environment in adjacent Carson City Park. Very little is known about the complex interactions between microbial communities, geochemistry and geophysics. In order to investigate possible connections between these parameters a multidisciplinary study was undertaken to investigate the hypothesis that the degradation of LNAPL by resident microbial communities causes a local increase in organic …


Geochemical And Isotopic Characteristics Associated With High Conductivities In A Shallow Hydrocarbon-Contaminated Aquifier, Franklyn D. Legall Dec 2002

Geochemical And Isotopic Characteristics Associated With High Conductivities In A Shallow Hydrocarbon-Contaminated Aquifier, Franklyn D. Legall

Dissertations

In-situ vertical resistivity probes (VRPs) deployed at a hydrocarboncontaminated site in SW Michigan showed high soil conductivities within the contaminated zone. Within this zone, different phases of hydrocarbon impact were recognized, namely, zones with residual and dissolved phase hydrocarbons (RDH) and zones where these phases coexist with free product (RDFH). Bulk soil conductivities were highest ( 12 to 30 mS/m) in the zone with RDFH compared to the RDH zone (10 to 25 mS/m). Groundwater chemistry and stable carbon isotope data from closely spaced vertical samples within the anomalous conductive zones were used to provide evidence for biodegradation and to …


Late Holocene Sea-Level Change Around Newfoundland, Julia Daly Aug 2002

Late Holocene Sea-Level Change Around Newfoundland, Julia Daly

Electronic Theses and Dissertations

Analysis of basal salt-marsh peats and tide-gauge data from several locations around Newfoundland yield high-resolution late Holocene sea-level reconstructions and constrain differential sea-level change. The transition between rising and falling local sea levels and the influence of glacioisostasy on relative sea-level change around Newfoundland through the late Holocene are not well known fiom previous research. The patterns of local relative sea-level change during this time have important implications for constraining numerical models of sea-level change, and therefore inferences about ice sheet thickness and the response of the lithosphere to deglaciation. I investigated the stratigraphy of salt marshes at four locations …


Genesis And Morphology Of Soil Pendants In Quaternary Landforms Of Pahranagat Valley, Nevada, Amy Lynn Brock Aug 2002

Genesis And Morphology Of Soil Pendants In Quaternary Landforms Of Pahranagat Valley, Nevada, Amy Lynn Brock

UNLV Theses, Dissertations, Professional Papers, and Capstones

Five geomorphic surfaces present in the northern Pahranagat Valley, Lincoln County, Nevada range in age from Early Pleistocene to Recent (Q1-Q5) and vary in clast lithology from dolomite to volcanic tephras. Two chronosequences and 5 lithosequences were compared to evaluate micro and macromorphic characteristics and development of soil pendants. This study presents a new interpretation for soil pendant development. Key features observed in the Pahranagat Valley pendants provide evidence for precipitation at the clast-pendant contact suggesting that newer deposits are not always found at the pendant terminus as other studies have assumed. These features include a void at the clast-pendant …


Biogeochemistry Of The Middle Rio Grande Bosque: Links Among Surface Water, Groundwater, And Sediments, Susan E. Block Jun 2002

Biogeochemistry Of The Middle Rio Grande Bosque: Links Among Surface Water, Groundwater, And Sediments, Susan E. Block

Earth and Planetary Sciences ETDs

The potential for water contamination is great in areas where land use is both urban and agricultural. Such land uses can load the surface water and groundwater with nutrients and toxic trace metals. Water pollution can be further increased when natural watersheds have been altered by human activities. The surface and groundwaters of the Middle Rio Grande, NM, USA are part of one such ecosystem.

Because redox processes are important controls on nutrient cycling and contaminant transport, it is vital to understand the redox zonation of an aquifer. This research has been conducted to address such biogeochemical zonation in the …


The Role Of Groundwater And Surface Water Interaction In The Development Of A 1,4-Dioxane Plume In Scio Township, Washtenaw County, Michigan, James W. Brode Jun 2002

The Role Of Groundwater And Surface Water Interaction In The Development Of A 1,4-Dioxane Plume In Scio Township, Washtenaw County, Michigan, James W. Brode

Masters Theses

The purpose of this study was to examine the hypothesis that groundwater and surface water interaction resulted in the development a 1,4-dioxane plume in a glacial aquifer in Scio Township, Washtenaw County, Michigan.

An industrial solvent, 1,4-dioxane, was detected in the groundwater in the area of study in 1986. This area, referred to in this investigation as the Western Plume, is one of several 1,4-dioxane plumes associated with the Pall/Gelman Sciences Inc. (P/GSI) site, an extensively investigated site of groundwater contamination.

1,4-Dioxane in the Western Plume area was initially believed to be the result of contaminated groundwater transported from a …


Multiple Isotopic Investigation Of Lake Sediments From Northern India, Alice Mwanda Jun 2002

Multiple Isotopic Investigation Of Lake Sediments From Northern India, Alice Mwanda

Masters Theses

Stable isotopes ratio of lake sediments can provide valuable environmental information. This possibility has been investigated using radiocarbon dated fossil lake sediments from the Himalayan region of Northern India. The chronology was established using Radiocarbon dating of both organic and inorganic fractions using (AMS). Inorganic ages are older than organic ages. Organic ages are expected to increase stratigraphically, however several anomalous old ages are found in the younger part of the sediments. Final chronology, determined using selected sensible ages identified two periods of sedimentation. The high sedimentation period is characterized by sedimentation rate of 0.8cm/yr and it fairly coincides with …


Evolution Of Seabed Pockmarks In Penobscot Bay, Maine, Allen M. Gontz May 2002

Evolution Of Seabed Pockmarks In Penobscot Bay, Maine, Allen M. Gontz

Electronic Theses and Dissertations

Seafloor depressions, called pockmarks, have been known to exist in Penobscot Bay, Maine since the mid 1980's (Knebel and Scanlon, 1985). Earlier workers (Ostericher, 1965) recognized "channels" on sonoprobe records that are in the sanle area as the pockmarks recognized by Knebel and Scanlon (1985). Their origins and pathways of evolution are unknown. Much speculation about the sources of pore fluids, levels of activity, and evolutionary pathways has occurred since their discovery. Two surveys of Belfast Bay, in 1998 and 1989, have shown differences in the pockmark field population. Over the course of a decade, 36% of the field's 1998 …


Stratigraphy And Paleoecology Of The Morrison Formation, Como Bluff, Wyoming, Melissa V. Connely May 2002

Stratigraphy And Paleoecology Of The Morrison Formation, Como Bluff, Wyoming, Melissa V. Connely

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Morrison Formation at Como Bluff, Wyoming, has been historically known for containing a rich source of Late Jurassic vertebrate fossils. However, when collected, most of these fossils were not positioned into a stratigraphic or sedimentologic framework. Research shows that the Morrison Formation at Como Bluff can be divided into three members. These members can be identified by lithologic and paleontological characteristics. The lower Morrison members include the Windy Hill Member and the recently described Lake Como Member. The Windy Hill Member primarily contains near-shore marine sandstone. Megavertebrate fauna is lacking. The Lake Como Member contains illitic clay in red …


Geology Of The Cuesta Ridge Ophiolite Remnant Near San Luis Obispo, California: Evidence For The Tectonic Setting And Origin Of The Coast Range Ophiolite, Cameron A. Snow May 2002

Geology Of The Cuesta Ridge Ophiolite Remnant Near San Luis Obispo, California: Evidence For The Tectonic Setting And Origin Of The Coast Range Ophiolite, Cameron A. Snow

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Cuesta Ridge ophiolite is one of the best-preserved remnants of mid-Jurassic ophiolite in California. Geologic mapping and petrologic studies show that it comprises (1) harzburgite mantle tectonite, (2) dunite-rich mantle transition zone (MTZ), (3) wehrlite and pyroxenite, (4) isotropic gabbro, (5) sheeted dike/sill complex, (6) volcanic rocks (7) late-stage dikes and flows, and (8) tuffaceous radiolarian chert.

The sheeted dike/sill complex is dominated by quartz diorite, with significant modal quartz and hornblende. The volcanic section is dominated by arc tholeiite and boninitic lavas. Boninites, with high MgO, Cr, and Ni comprise 40% of the volcanic rocks. Latestage dikes and …


Sedimentology, Facies Architecture, And Reservoir Characterization Of Lacustrine Rocks, Eocene Green River And Colton Formations, Uinta Basin, Utah, Andrew W. Taylor May 2002

Sedimentology, Facies Architecture, And Reservoir Characterization Of Lacustrine Rocks, Eocene Green River And Colton Formations, Uinta Basin, Utah, Andrew W. Taylor

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Outcrop and petrographic studies of the Eocene Green River and Colton formations in the Uinta basin, Utah, document the facies architecture and heterogeneity characteristic of lacustrine reservoirs. A southwest-northeast transect of Eocene strata in the Uinta basin records three main marginal lacustrine depositional environments: fluvial, deltaic, and wave-dominated. Heterogeneity exists between and within individual depositional systems.

Reservoir rocks of Outcrops One and Two (the flu vial facies of the Colton Formation and the deltaic facies of the Green River Formation, respectively) consist of 2 to 18 m thick lenticular, tabular, or undulatory channel-fill, distributary channel, and distributary mouth bar deposits …


Evolution Of A Miocene-Pliocene Low-Angle Normal-Fault System In The Southern Bannock Range, Southeast Idaho, Stephanie M. Carney May 2002

Evolution Of A Miocene-Pliocene Low-Angle Normal-Fault System In The Southern Bannock Range, Southeast Idaho, Stephanie M. Carney

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Geologic mapping, basin analysis, and tephrochronologic analysis in the Clifton quadrangle of southeast Idaho indicates that the modern Basin-and-Range topography is only a few million years old and that the bulk of Cenozoic extension was accommodated by slip on an older low-angle normal-fault system, the Bannock detachment system. The detachment system was active between ~12 and < 4 Ma and accommodated ~50 % extension.

Cross-cutting relationships show that the master detachment fault, the Clifton fault, is the youngest low-angle normal fault of the system, was active at a low angle, and has not been rotated to a low-dip angle through time. Map patterns and relationships indicate that the …


Geometry And Physical Properties Of The Chelungpu Fault, Taiwan, And Their Effect On Fault Rupture, Richard V. Heermance May 2002

Geometry And Physical Properties Of The Chelungpu Fault, Taiwan, And Their Effect On Fault Rupture, Richard V. Heermance

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rupture of the Chelungpu fault during the September 21, 1999, 7.6 Mwearthquake in Taiwan caused a 90-Jr,m-long surface rupture with variable displacement along strike. Analysis of core from two holes drilled through the fault zone, combined with geologic mapping and detailed investigation from three outcrops, define the fault geometry and physical properties of the Chelungpu fault in its northern and southern regions. In the northern region, the fault dips 45-60° east parallel to bedding and consists of a narrow (1-20 cm) core of dark-gray, sheared clay gouge at the base of a 30-50 m zone of increased fracture …


Relationships Between Tributary Catchments, Valley-Bottom Width, Debris-Fan Area, And Mainstem Gradient On The Colorado Plateau: A Case Study In Desolation And Gray Canyons On The Green River, Caroline M. Elliott May 2002

Relationships Between Tributary Catchments, Valley-Bottom Width, Debris-Fan Area, And Mainstem Gradient On The Colorado Plateau: A Case Study In Desolation And Gray Canyons On The Green River, Caroline M. Elliott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The alluvial forms of the rivers that drain the Colorado Plateau are a product of the water and sediment load that tributaries deliver to the trunk streams. Where the Green and Colorado Rivers cross structural barriers, narrow canyons have been incised. In the steep terrain adjacent to many of these canyons debris flows occur in the catchment basins of tributaries and deliver coarse sediment to the mainstem river corridor. Over time, debris flow deposits have aggraded in trunk stream valleys and created landforms known as debris fans. The sizes of these debris fans are related to the accommodation space available …


The Stratigraphic, Sedimentologic, And Paleogeographic Evolution Of The Eocene- Oligocene Grasshopper Extensional Basin, Southwest Montana, Joseph P. Matoush May 2002

The Stratigraphic, Sedimentologic, And Paleogeographic Evolution Of The Eocene- Oligocene Grasshopper Extensional Basin, Southwest Montana, Joseph P. Matoush

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Grasshopper basin, located in southwest Montana, is an east-tilted graben bounded by the listric Muddy-Grasshopper fault and the Meriwether Lewis fault on the eastern and western margins of the basin, respectively. This basin contains a complex stratigraphy of intertonguing facies comprised of five unconformity-bounded sequences of Tertiary alluvial, flu vial, deltaic, and lacustrine sedimentary and volcanic rocks. Sequence 1 consists of the Challis volcanic Group (Middle Eocene). The sedimentary rocks of the Medicine Lodge beds (Late Eocene-Late Oligocene) represent sequence 2 and approximately 90% of the basin-fill within Grasshopper basin. Sequence 3 consists 11 of the Sedimentary Rocks of Everson …


Structural And Kinematic Evolution Of Eocene-Oligocene Grasshopper Extensional Basin, Southwest Montana, Julie C. Kickham May 2002

Structural And Kinematic Evolution Of Eocene-Oligocene Grasshopper Extensional Basin, Southwest Montana, Julie C. Kickham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Grasshopper basin of southwest Montana is a complex east-dipping graben containing five unconformity-bounded sequences of Tertiary sedimentary rocks. The Eocene-Oligocene basin lies within the northern Rocky Mountain Basin and Range province. Geologic mapping in five and a half 7.5 minute quadrangles indicates that at least three distinct phases of extension characterize the Cenozoic tectonic evolution of Grasshopper basin from approximately 46 Ma to < Ma.

The significant phases of extension in Grasshopper basin were phases 1 and 3. During the first phase of extension (46-27 Ma) the nonplanar Muddy-Grasshopper fault was initiated and 90% of the basin fill was deposited. At …


Distribution Of Patterned Ground And Surficial Deposits On A Debris-Covered Glacier Surface In Mullins Valley And Upper Beacon Valley, Antarctica, Andrew M. Lorrey May 2002

Distribution Of Patterned Ground And Surficial Deposits On A Debris-Covered Glacier Surface In Mullins Valley And Upper Beacon Valley, Antarctica, Andrew M. Lorrey

Electronic Theses and Dissertations

Beacon Valley is located in the western Dry Valleys, Antarctica, adjacent to the East Antarctic Ice Sheet (EAIS). The surficial material on the floor of Beacon Valley is segmented into large polygonal landforms separated by trenches. Buried beneath the polygons and surficial material is massive ground ice. One hypothesis is that the buried ice in upper Beacon Valley is glacier ice originating from local debris-covered glaciers. The networks of polygons and trenches form as the buried ice undergoes thermal contraction and sublimation. Contraction cracks that penetrate the surficial material and buried ice in Beacon Valley contain Late Miocene age volcanic …


Defining The Hayesville–Soque River And Allatoona Faults And An Ordovician Arc Assemblage Within The Central Blue Ridge Northwest Of Dahlonega, Georgia, David Jonathan Settles May 2002

Defining The Hayesville–Soque River And Allatoona Faults And An Ordovician Arc Assemblage Within The Central Blue Ridge Northwest Of Dahlonega, Georgia, David Jonathan Settles

Masters Theses

The goal of this research within the central Blue Ridge northwest of Dahlonega, Georgia, is to provide new information toward better understanding of the Allatoona(?)/ Hayesville/Gossan Lead fault and terrane boundary, and to provide convincing evidence of Ordovician arc-related igneous activity. The Hayesville-Soque River and Allatoona faults separate three distinct tectonostratigraphic assemblages in this area: the Coweeta Group, Great Smoky Group, and Dahlonega gold belt. The gold belt here contains metasandstone, pelitic schist, and mafic rocks of the Otto Formation and the Sally Free mafic complex, while the Great Smoky Group contains metasandstone and pelitic schist with abundant calc-silicate. The …


Stratigraphic Analysis Of Diamicton Units In Southern Allegan County, Michigan, Shannon A. Wong Apr 2002

Stratigraphic Analysis Of Diamicton Units In Southern Allegan County, Michigan, Shannon A. Wong

Masters Theses

Two diamicton units from the southern Allegan County, Michigan lakeshore bluffs were identified and differentiated through clay mineralogy by analysis of 7 /10A peak-height ratios and the 2-80 mm crystalline fraction from pebble count results. t-Tests indicate the two units are significantly different. These two units are correlated with the Saugatuck and the Ganges tills of southwest Michigan based on similarities in stratigraphic position and lithologic description as described by Monaghan et al. (1986). Other diamicton samples were collected throughout southwest Michigan, near Moline, Otsego, Bloomingdale, Gobles, and Decatur. In correlating the Saugatuck and the Ganges tills to their inland …


Determining Flow Type In A Carbonate Bedrock Aquifer, Presque Isle County, Michigan, Bonny Armstrong Apr 2002

Determining Flow Type In A Carbonate Bedrock Aquifer, Presque Isle County, Michigan, Bonny Armstrong

Masters Theses

Presque Isle County, Michigan, has a long history of ground water quality problems. Aquifer contamination is most likely the result of large fractures in the bedrock allowing surface water to rapidly reach ground water. The purpose of the study is to l) perform a geochemical investigation of ground water in the bedrock aquifer, 2) suggest the type of ground water flow system present in the study area and characterize the aquifer type, and 3) suggest how the flow system might affect the behavior and transport of contaminants.

Water samples were collected from sixteen wells in the Genshaw Formation, three wells …


A Late Pleistocene And Holocene High-Resolution Glacial And Paleoclimate Record From The Southern Sangre De Cristo Mountains, Northern New Mexico, Jake Armour Mar 2002

A Late Pleistocene And Holocene High-Resolution Glacial And Paleoclimate Record From The Southern Sangre De Cristo Mountains, Northern New Mexico, Jake Armour

Earth and Planetary Sciences ETDs

Bog deposits in the Winsor Creek drainage basin, southern Sangre de Cristo Mountains, New Mexico contain a high-resolution record of Pleistocene to Holocene glacial activity. Sediment cores were recovered from an alpine bog (elevation 3,100 m) behind a Pinedale age moraine, 2 km from a high-elevation (-3600 m) cirque. Three cores reached glacial talus and consist of -6 meters of finely laminated to coarsely laminated lake clays, grading into gyttja. Superimposed on this long-term, lake-bog transition record are many distinct coarse-grained detrital packages punctuating times of rapid environmental change.

Accelerator mass spectrometry (AMS) carbon dating, sedimentology, variations in rock magnetic …


Sedimentology And Paleoenvironments Of The Miocene/Pliocene Pisco Fm., Perú, Cristian R. Carvajal Mar 2002

Sedimentology And Paleoenvironments Of The Miocene/Pliocene Pisco Fm., Perú, Cristian R. Carvajal

Loma Linda University Electronic Theses, Dissertations & Projects

The main objective of this research was to understand the sedimentology and depositional environment of the diatomaceous Miocene/Pliocene Pisco Formation in the Ica Valley, Perú. Four stratigraphic sections were studied, sampled and correlated. Field data were integrated with XRD, diatom taxonomy and taphonomy, and thin section analyses to define six facies.

Facies A is composed of diatomaceous siltstone with scour and fill structures formed on a shallow shelf. Facies B was deposited on the transitional zone between the shallow shelf and nearshore where tuffaceous-diatomaceous siltstone and sandstone accumulated. In facies B, lenticular laminations, and flaser, wavy and lenticular bedding record …


Impact Spherules From Western Australia: A Textural Analysis Of Really Old Tiny Rocks, Dawn C.S. Ruth Jan 2002

Impact Spherules From Western Australia: A Textural Analysis Of Really Old Tiny Rocks, Dawn C.S. Ruth

Honors Papers

The fourth shale macroband of the Dales Gorge Member of the Brockman Iron Formation in the Hamersley Basin in Western Australia contains a 2.49 billion years-old impact ejecta layer (Hassler and Simonson,2001). The S4 layer is the least studied Paleoproterozoic impact layer in the Hamersley Basin. It displays textures and replacement minerals not seen in other layers. Analysis of this layer will help our understanding of the processes that form impact ejecta, especially in the Paleoproterozoic.

It is believed that these ejecta settled in a deep basin environment; laterally extensive beds and mud-sized grains are evidence of the deep basin …


Field Relations, Structural Geology, And Geochemistry Of The Jonestown Volcanic Field, Lebanon County, Southeastern Pennsylvania, Tristan J. Ashcroft Jan 2002

Field Relations, Structural Geology, And Geochemistry Of The Jonestown Volcanic Field, Lebanon County, Southeastern Pennsylvania, Tristan J. Ashcroft

Geology Theses and Dissertations

The Jonestown Volcanic Field is a five kilometer by fifteen kilometer area of volcanic and hypabyssal rocks, basalt and diabase, located in southeastern Pennsylvania. These igneous rocks presently occur within an allochthonous belt of Ordovician deep water sedimentary rocks and Taconic flysch rocks known collectively as the Hamburg Klippe. Detailed field mapping during this project has revealed that the contacts between the igneous rocks and the flysch are not conformable. The volcanic rocks are associated with the Ordovician limestone that is adjacent to these volcanics. This limestone also is not conformable to the Hamburg Klippe sediments, rather it shares outcrop …


The Use Of A Synthetic Binary Solid Solution To Model Igneous Textural Evolution, Elizabeth Scott Jan 2002

The Use Of A Synthetic Binary Solid Solution To Model Igneous Textural Evolution, Elizabeth Scott

Geology Theses and Dissertations

Crystallization experiments using a synthetic igneous analog have shown that grain boundary migration can take place in melt-present environments (Means and Park, 1994). In order to evaluate the importance of metamorphic processes during the textural evolution of a crystal mush, microstructural evidence is needed to link them with final igneous textures. In natural magmatic systems, plagioclase may provide a microstructural link; plagioclase solid solution enables the process of chemical zoning and preserves a record of crystal morphology (and chemistry) during growth. If metamorphic processes are common, they should affect the zoning patterns of plagioclase crystals.
A petrographic stage heater apparatus …


Surficial Geology And Geomorphology Of The Western Olympus Range, Antarctica: Implications For Ice-Sheet History, Brett Vandenheuvel Jan 2002

Surficial Geology And Geomorphology Of The Western Olympus Range, Antarctica: Implications For Ice-Sheet History, Brett Vandenheuvel

Electronic Theses and Dissertations

A widespread erosion surface passes across bedrock and sedimentary deposits in the western Dry Valleys sector of the Transantarctic Mountains (TAM), southern Victoria Land, Antarctica. The surface includes stoss-and-lee slopes, channels, potholes, scoured basins, and corrugated bedrock. These features have been taken to represent subglacial meltwater erosion beneath a greatly expanded East Antarctic Ice Sheet (EAIS) in the mid-Miocene (Denton et al. 1984, Marchant et al. 1993a). Sedimentary deposits that are typically associated with ice-sheet wastage, such as outwash, are not present on the erosion surface. The lack of these deposits indicates that the expanded ice-sheet postulated to be responsible …