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

Geology Commons™

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

29,938 Full-Text Articles 16,127 Authors 6,782,393 Downloads 178 Institutions

All Articles in Geology

Faceted Search

29,938 full-text articles. Page 1231 of 1248.

Molecular Organic Geochemistry Of The Oil And Source Rocks In Railroad Valley, Eastern Great Basin, Nevada, United States, LaOde Ahdyar 2011 University of Nevada, Las Vegas

Molecular Organic Geochemistry Of The Oil And Source Rocks In Railroad Valley, Eastern Great Basin, Nevada, United States, Laode Ahdyar

UNLV Theses, Dissertations, Professional Papers, and Capstones

A comprehensive geochemical study of oils from Railroad Valley, Nevada and two candidate source rock intervals from the nearby Egan Range, was conducted in order to establish oil-oil and oil-source rock correlations. Analyses consisted of total organic carbon, Rock-Eval pyrolysis, and vitrinite reflectance for source rock samples, as well as biomarker, diamondoids, and stable carbon isotope analyses on source rock extracts and oil samples.

Total organic carbon analyses showed high organic content in the Mississippian Chainman Shale. However, outcrop samples of the Paleogene Sheep Pass Formation Member B are organically lean. Strata in both of these units are immature to …


Vertebrate Taxonomic Composition, Species Diversity, And Paleoecology Of Two Pliocene Mid-Latitude, Inland-Basin Fossil Assemblages: Panaca Local Fauna (Lincoln County, Nevada) And Hagerman Local Fauna (Twin Falls County, Idaho), Vicki Lynn Meyers 2011 University of Nevada, Las Vegas

Vertebrate Taxonomic Composition, Species Diversity, And Paleoecology Of Two Pliocene Mid-Latitude, Inland-Basin Fossil Assemblages: Panaca Local Fauna (Lincoln County, Nevada) And Hagerman Local Fauna (Twin Falls County, Idaho), Vicki Lynn Meyers

UNLV Theses, Dissertations, Professional Papers, and Capstones

I studied the sedimentology, species diversity, relative abundance, paleoenvironment, and paleoecology of the vertebrate fauna of the early Pliocene (Blancan Land Mammal Age) Panaca Formation of southeastern Nevada, and I compared these data with the slightly younger Hagerman fauna of south-central Idaho. The purpose of this study is to characterize the paleoecology and species diversity of mid-latitude inland basins during the Blancan Land Mammal Age, a time of climate change and immigrating taxa from Asia and South America. This study involved surface collecting and screenwashing of the Panaca Formation sediment in Meadow Valley, as well as a compilation of data …


Geochemical Controls On Mercury Methylation In Backwaters Of A Gulf Coastal Plain River System, Implications For Water Column Processes, Liam N. Schenk 2011 University of Arkansas, Fayetteville

Geochemical Controls On Mercury Methylation In Backwaters Of A Gulf Coastal Plain River System, Implications For Water Column Processes, Liam N. Schenk

Graduate Theses and Dissertations

The abundance and distribution of mercury and methyl mercury were investigated at three sites in the lower Ouachita River in the summer of 2010 in an effort to provide the first characterization of the extent of mercury contamination in this river system, and to investigate the potential for mercury methylation in the water column of backwaters off of the main channel. Results showed that filtered methyl mercury was positively correlated to dissolved organic carbon (r2=0.76) for water samples taken from the bottom 1 ft of the water column at three sites, suggesting the importance of dissolved organic carbon in mercury …


Pleistocene Climate In Alaska From Stable Isotopes In An Ice Wedge, Corinne Y. Griffing 2011 University of Nevada, Las Vegas

Pleistocene Climate In Alaska From Stable Isotopes In An Ice Wedge, Corinne Y. Griffing

UNLV Theses, Dissertations, Professional Papers, and Capstones

The CRREL permafrost tunnel offers a unique opportunity to sample ice wedges in a climate-controlled environment, penetrating frozen silts which host massive ground ice that may record Dansgaard-Oeschger (D-O) and Heinrich Events. Ice wedges in the tunnel have been dated to approximately 36-22 ka (Hamilton et al., 1988), allowing the paleoclimate of the region to be reconstructed during MIS 3, when D-O and Heinrich events were documented in various other records. These climate cycles are rapid climate oscillations that have been recognized in records from the Arctic and subarctic, and suggest that climate can rapidly shift by 10°C over millennial …


Lateral Variability Of Facies And Cycles In The Furongian (Late Cambrian) Carbonate Platform: An Example From The Big Horse Member Of The Orr Formation In Western Utah, U.S.A., Ratna Widiarti 2011 University of Nevada, Las Vegas

Lateral Variability Of Facies And Cycles In The Furongian (Late Cambrian) Carbonate Platform: An Example From The Big Horse Member Of The Orr Formation In Western Utah, U.S.A., Ratna Widiarti

UNLV Theses, Dissertations, Professional Papers, and Capstones

Carbonate depositional cycles and sequences have been proposed to be formed by glacioeustatic sea-level changes. This mechanism would be questionable during times of high atmospheric CO2 and negligible continental ice sheets such as the supergreenhouse time in the Furongian (late Cambrian), during which limited glacioeustatic sea-level changes would be expected. A detailed sedimentological study of the Furongian Orr Formation in western Utah is aimed at testing the hypothesis that, under supergreenhouse climate conditions, most meter-scale carbonate cycles may have been formed through autocyclic processes and thus they should be laterally variable. The research was conducted in a small area ( …


Extent Of Gully Erosion In An Agricultural Field In Northeastern Nebraska At Section 35 Township 29 North Range 1 West In Cedar County, Crystal Starkel 2011 University of Nebraska-Lincoln

Extent Of Gully Erosion In An Agricultural Field In Northeastern Nebraska At Section 35 Township 29 North Range 1 West In Cedar County, Crystal Starkel

Department of Environmental Studies: Undergraduate Student Theses

My thesis project examined a gully within Section 35 Township 29 North Range 1 West. This gully has been noticed for five years and has grown substantially in those five years. The extent and causes of gully erosion were examined by considering the soil, the climate, the land management history, by measuring the gully physically, by using GIS, and by using an economic support tool was estimate soil loss. Appropriate recommendations were developed to reduce gully erosion.


From Hillslopes To Canyons, Studies Of Erosion At Differing Time And Spatial Scales Within The Colorado River Drainage, Christopher Tressler 2011 Utah State University

From Hillslopes To Canyons, Studies Of Erosion At Differing Time And Spatial Scales Within The Colorado River Drainage, Christopher Tressler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis includes two different studies in an attempt to investigate and better understand the key characteristics of landscape evolution. In the first study, the rate of surface particle creep was investigated through the use of Terrestrial lidar at an archaeological site in Grand Canyon National Park. The second study developed ways to quantify metrics of the Colorado River drainage and reports the role of bedrock strength in the irregular profile of the trunk Colorado River drainage.

Archaeological sites along the Colorado River corridor in Grand Canyon National Park are eroding due to a variety of surficial processes. The nature …


Stratigraphic, Microfossil, And Geochemical Analysis Of The Neoproterozoic Uinta Mountain Group, Utah: Evidence For A Eutrophication Event?, Dawn Schmidli Hayes 2011 Utah State University

Stratigraphic, Microfossil, And Geochemical Analysis Of The Neoproterozoic Uinta Mountain Group, Utah: Evidence For A Eutrophication Event?, Dawn Schmidli Hayes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several previous Neoproterozoic microfossil diversity studies yield evidence for a relatively sudden biotic change prior to the first well‐constrained Sturtian glaciations. In an event interpreted as a mass extinction of eukaryotic phytoplankton followed by bacterial dominance, diverse assemblages of complex acritarchs are replaced by more uniform assemblages consisting of simple leiosphaerid acritarchs and bacteria. Recent data from the Chuar Group of the Grand Canyon (770‐742 Ma) suggest this biotic change was caused by eutrophication rather than the direct effects of Sturtian glaciation; evidence includes total organic carbon increases indicative of increasing primary productivity followed by iron speciation values that suggest …


Sedimentological Controls On Fracture Distribution And The Network Development Within Meseverde Group Lithofacies, Uinta Basin, Utah, Ryan Christopher Sonntag 2011 Utah State University

Sedimentological Controls On Fracture Distribution And The Network Development Within Meseverde Group Lithofacies, Uinta Basin, Utah, Ryan Christopher Sonntag

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Mesaverde Group, within the Uinta Basin, Utah, is a source of current significant production and contains several trillion cubic feet of undiscovered natural gas resources. Due to the low permeability of the matrix rock, understanding the geometry and properties of natural fractures is critical to the development of effective ways of finding and producing natural gas. In order to evaluate and model the potential connectivity of hydraulically induced fractures to natural fractures at depth, we examine the nature of the natural fracture network using scanline sampling, imagery analyses, core analyses, and microstructural analyses. Regional fracture sets identified include: N-S …


Salt Contamination Of Ground And Surface Water In Connecticut: A Compilation And Synthesis Of Historic Data And Local Scale Testing, James P. Cassanelli 2011 University of Connecticut

Salt Contamination Of Ground And Surface Water In Connecticut: A Compilation And Synthesis Of Historic Data And Local Scale Testing, James P. Cassanelli

Master's Theses

No abstract provided.


Geologic Mapping Of Exhumed, Mid-Cretaceous Paleochannel Complexes Near Castle Dale, Emery County, Utah: On The Correlative Relationship Between The Dakota Sandstone And The Mussentuchit Member Of The Cedar Mountain Formation, Amanda Elizabeth MacKay Sorensen 2011 Brigham Young University - Provo

Geologic Mapping Of Exhumed, Mid-Cretaceous Paleochannel Complexes Near Castle Dale, Emery County, Utah: On The Correlative Relationship Between The Dakota Sandstone And The Mussentuchit Member Of The Cedar Mountain Formation, Amanda Elizabeth Mackay Sorensen

Theses and Dissertations

Numerous well-preserved, exhumed paleochannels in the Morrison, Cedar Mountain and Dakota Sandstone formations are exposed east of Castle Dale, Utah. These channels consist primarily of point bar complexes and scattered, low sinuosity channels. To determine the vertical and lateral relationships of these channels within the Cedar Mountain and Dakota Sandstone formations, a 1:24,000 scale geologic map covering ~140 km2 was created showing the fluvial sandstones. In the study area the Cedar Mountain Formation consists, from bottom to top, of 2.5-10 m of Buckhorn Conglomerate Member equivalent units, ~80 m of the Ruby Ranch Member, and ~30 m of the Mussentuchit …


Serpentinite Weathering And Implications For Mars, Valerie Tu, Julie Baumeister, Rodney Metcalf, A. Olsen, Elisabeth Hausrath 2011 University of Nevada, Las Vegas

Serpentinite Weathering And Implications For Mars, Valerie Tu, Julie Baumeister, Rodney Metcalf, A. Olsen, Elisabeth Hausrath

Festival of Communities: UG Symposium (Posters)

In the search for life on Mars near-surface soil environments may be important habitats for life accessible to future missions. Serpentinite rocks have been documented on Mars, as well as other clay minerals including smectite and kaolinites. Previous studies of soils formed on serpentinites on Earth have documented the formation of extensive clays. Serpentinites are additionally of interest as habitats for life such as methanogens. Here we examine weathering of serpentinites from bedrock to soil surface, as a potential route for the formation of clay minerals on Mars from abundant ultramafic minerals. We additionally test for the presence of Fe-oxidizing …


Effects Of Rodent Species, Seed Species, And Predator Cues On Seed Fate, Kelly J. Sivy, Steven M. Ostoja, Eugene W. Schupp, Susan Durham 2011 Utah State University

Effects Of Rodent Species, Seed Species, And Predator Cues On Seed Fate, Kelly J. Sivy, Steven M. Ostoja, Eugene W. Schupp, Susan Durham

United States Geological Survey: Staff Publications

Seed selection, removal and subsequent management by granivorous animals is thought to be a complex interaction of factors including qualities of the seeds themselves (e.g., seed size, nutritional quality) and features of the local habitat (e.g. perceived predator risk). At the same time, differential seed selection and dispersal is thought to have profound effects on seed fate and potentially vegetation dynamics. In a feeding arena, we tested whether rodent species, seed species, and indirect and direct predation cues influence seed selection and handling behaviors (e.g., scatter hoarding versus larder hoarding) of two heteromyid rodents, Ord’s kangaroo rat (Dipodomys ordii) and …


Conservation In Conflict: Reconciling Resource Management Perspectives In A "Geographical Mosaic", Kate Wright '11 2011 DePauw University

Conservation In Conflict: Reconciling Resource Management Perspectives In A "Geographical Mosaic", Kate Wright '11

Honor Scholar Theses

No abstract provided.


Historic And Contemporary Trends Of The Conservation Reserve Program And Ring-Necked Pheasants In South Dakota, Chris Laingen 2011 Eastern Illinois University

Historic And Contemporary Trends Of The Conservation Reserve Program And Ring-Necked Pheasants In South Dakota, Chris Laingen

Faculty Research and Creative Activity

Over the past century, the interactions between agricultural land use and government cropland retirement programs have affected pheasant population change. Two government land retirement programs that returned croplands to grasslands, Soil Bank in the 1960s and the current Conservation Reserve Program (CRP), help to illustrate these connections. From 2007 to 2010, South Dakota lost 41% of its CRP lands and experienced an 18% decline in pheasants per mile. However, because of where CRP expirations have occurred and where pheasant populations are found , some regional variability is seen. Western South Dakota (Region 1) had an 80% increase in pheasants per …


Spring Hydrology Of Colorado Bend State Park, Central Texas, Kevin W. Stafford, Melinda G. Shaw-Faulkner, Jessica L. DeLeon 2011 College of Sciences and Mathematics, Department of Geology, Stephen F. Austin State University

Spring Hydrology Of Colorado Bend State Park, Central Texas, Kevin W. Stafford, Melinda G. Shaw-Faulkner, Jessica L. Deleon

Faculty Publications

Karst development in Ellenburger carbonates near Colorado Bend State Park in central Texas exhibits complex polygenetic origins, with porosity development dominated by an early hypogene phase that has subsequently been overprinted to varying degrees by epigene processes. Quarterly physicochemical and continuous thermal monitoring analyses of eight springs in the study area indicate that modern groundwater flow paths are highly variable. Springs exhibit patterns that range from shallow, distributed recharge into diffuse-flow dominated systems, to focused recharge into well-connected conduit systems, to deep-circulation systems that equilibrate with bedrock. All springs, except Sulphur Spring, exhibit physicochemical characteristics indicative of proximal epigenic groundwater …


High Resolution Depositional Analysis Of The Black River Group (Ordovician), Michigan Basin, Jennifer Elaine Schulz 2011 Western Michigan University

High Resolution Depositional Analysis Of The Black River Group (Ordovician), Michigan Basin, Jennifer Elaine Schulz

Masters Theses

The Ordovician Trenton and Black River carbonates of the Michigan Basin are significant hydrocarbon reservoirs that are characterized by hydrothermal dolomitization. Production has exceeded 132 million barrels of oil with forty new discoveries made in the past three years. The giant Albion-Scipio Trend is often used as a model for other prolific hydrothermal dolomite reservoirs around the world with current models focused on the structural control of reservoir quality dolomite.

Previous studies of the Black River Group have not delimited a well-constrained depositional model. This study integrates high-resolution core interpretations, whole core analysis, and thin section evaluation to determine how …


Prediction Of Petrophysical Properties Of Trenton-Black River (Ordovician) Reservoirs By Comparing Pore Architecture And Permeability To Sonic Velocity, John E. Thornton 2011 Western Michigan University

Prediction Of Petrophysical Properties Of Trenton-Black River (Ordovician) Reservoirs By Comparing Pore Architecture And Permeability To Sonic Velocity, John E. Thornton

Masters Theses

Reservoir characterization of carbonate rocks is complicated by heterogeneous pore architecture related to primary depositional facies and subsequent diagenesis; this is especially true in diagenetically-altered and structurually-influenced Trenton-Black River reservoirs of the Michigan Basin. Accurate and reliable prediction of reservoir properties within hydrothermal dolomite reservoirs through the use of acoustic properties would aid exploration and characterization both within and outside of the Michigan Basin.

Results indicate that measures of pore architecture when integrated with measures of physical properties into multiple variable linear regression can accurately predict permeability of core plugs. However, due to the highly-heterogeneous distribution of pore architecture and …


The Role Of Underflows And Climate On Sediment Distribution In Glacial-Fed Lake Linné, Svalbard, Norway, Diana Zamora-Reyes^, Vanessa L. Lougheed, Alan Werner, Steven Roof* 2011 Department of Biological Sciences, University of Texas at El Paso

The Role Of Underflows And Climate On Sediment Distribution In Glacial-Fed Lake Linné, Svalbard, Norway, Diana Zamora-Reyes^, Vanessa L. Lougheed, Alan Werner, Steven Roof*

COURI Symposium Abstracts, Spring 2011

Linnévatnet (78° 2’N, 13° 49’E), is a glacial-fed lake located in Svalbard, an archipelago north of Norway. Sediments found in the lake are supplied by the Linné Glacier, 8km south of the lake, and are transported by the melt stream into the lake, creating laminations with a strong signal of seasonal deposition. Due to its immaculate environment and recent rapid increase in temperature, this site is an ideal place to study past-climate proxies and determine how the changing environment is affecting the area. The objective of this study is to determine the frequency of water underflows influencing sediment distribution and …


Investigation Of Carbon Sequestration Potential Of The Middle Devonian Sylvania Sandstone, Michigan Basin, U.S.A, Farsheed Rock 2011 Western Michigan University

Investigation Of Carbon Sequestration Potential Of The Middle Devonian Sylvania Sandstone, Michigan Basin, U.S.A, Farsheed Rock

Masters Theses

The Sylvania Sandstone is an important brine reservoir in Michigan. This study investigates the geological carbon sequestration potential of this reservoir through integrated reservoir characterization using cores, thin sections, core analysis data and modern wireline log data.

Core-to-wireline-log correlation can be used to subdivide the Sylvania Sandstone into conventional reservoir sandstone, and mixed dolostone, low permeability reservoir tripolitic chert and low permeability limestone lithologies. Isolith maps and cross sections indicate that the reservoir sandstone lithology dominates in southeast Michigan and is transitional to a mixture of sandstone, dolostone, tripolitic chert and limestone lithologies toward the northwest that in turn are …


Digital Commons powered by bepress