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

Geology Commons™

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

2012

Discipline
Institution
Keyword
Publication
Publication Type

Articles 121 - 150 of 285

Full-Text Articles in Geology

The Fluvial Muddy Creek Formation Near Overton, Nevada, Carl Taylor Swenberg May 2012

The Fluvial Muddy Creek Formation Near Overton, Nevada, Carl Taylor Swenberg

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Muddy Creek Formation (MCF) may represent an ancestral Colorado River deposit. To test this hypothesis, I mapped exposures of the MCF within the Virgin River Depression (VRD), a rift basin in the central Basin and Range. This is the first study to analyze fluvial MCF facies and test their viability as ancestral Colorado River deposits.

Mapping, paleocurrent analysis, conglomerate provenance, and architectural elements analysis were used in order to characterize the fluvial MCF near Overton NV. Architectural elements analysis revealed that MCF fluvial facies are most closely associated with those of a high-energy sand-bed braided river system. These results …


Chemical Weathering Of The Mafic Minerals Serpentine And Olivine In Natural Environments, Julie Lynn Baumeister May 2012

Chemical Weathering Of The Mafic Minerals Serpentine And Olivine In Natural Environments, Julie Lynn Baumeister

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chemical weathering is a critical process that plays a key role in controlling the chemistry of natural waters, the cycling of atmospheric carbon dioxide, and the formation of soil. The weathering of silicate minerals is important because the Earth's crust is composed of approximately 92 weight percent silicate minerals. Despite an extensive literature on mineral dissolution and kinetics, relatively few studies have examined weathering of the mafic minerals serpentine and olivine, especially in a natural environment. The first chapter of this thesis provides an introduction to the minerals serpentine and olivine. The second chapter of this thesis examines the important …


From The Foreland To The Hinterland: Taphonomy Across The Cretaceous To Paleogene Sevier Retroarc Region Of Nevada, Joshua William Bonde May 2012

From The Foreland To The Hinterland: Taphonomy Across The Cretaceous To Paleogene Sevier Retroarc Region Of Nevada, Joshua William Bonde

UNLV Theses, Dissertations, Professional Papers, and Capstones

Until 2004 very little paleobiology, let alone paleoecology, had been studied within exposures of the Sevier retro-arc foreland and hinterland, in the state of Nevada. This is due largely to poor and spotty exposure. This study focuses on taphonomic processes within three stratigraphic intervals in the foreland and hinterland of the Sevier retro-arc region, and what these taphonomic indicators reveal about the geography of the hinterland.

First, the Willow Tank Formation of southern Nevada was deposited in the foredeep of the Sevier retroarc foreland basin. This unit represents a multi-channel, aggradational, fluvial system that drained the Sevier highlands to the …


The Effects Of Salt Diapirs On The Thermal Maturity Of Surrounding Sediments In The Western Pyrenees, Spain, Nicholas Martin Downs May 2012

The Effects Of Salt Diapirs On The Thermal Maturity Of Surrounding Sediments In The Western Pyrenees, Spain, Nicholas Martin Downs

UNLV Theses, Dissertations, Professional Papers, and Capstones

Salt diapirs have been modeled as having a large effect on the thermal maturity of surrounding sediments as a result of the high thermal conductivity contrast between halite and other lithologies. The goal of this study was to confirm these and other theoretical predictions through sampling of three salt structures in the western Pyrenees, Spain. Stratigraphic units around these three diapirs were targeted based on their lithologies and positions relative to the diapirs. Samples were analyzed for vitrinite reflectance and quartz cementation to determine their levels of thermal maturity. Remote sensing instruments were used to attempt to measure present day …


Paleobiological Assessment Of Controls Underlying Long-Term Diversity Dynamics, Andrés L. Cárdenas Apr 2012

Paleobiological Assessment Of Controls Underlying Long-Term Diversity Dynamics, Andrés L. Cárdenas

USF Tampa Graduate Theses and Dissertations

Deciphering the factors underlying both long-term patterns of diversity and taxonomic turnover rates (i.e., extinction, and origination) has been one of Paleobiology's major foci for the past three decades. The importance of documenting these components is that they will expand our ability to interpret and model the evolutionary processes underlying those trends, highlight the evolutionary impact of historical events, and contribute to the formulation of robust predictions about the future of global diversity in response to the current anthropologically driven environmental changes. Accordingly, the first part of this study examines the possible occurrence of global marine evolutionary environmental controls into …


Bulk Rock Composition And Geochemistry Of Olivine-Hosted Melt Inclusions In The Grey Porri Tuff And Selected Lavas Of The Monte Dei Porri Volcano, Salina, Aeolian Islands, Southern Italy., Angela L. Doherty, Robert J. Bodnar, Benedetto De Vivo, Wendy A. Bohrson, Harvey E. Belkin, Antonia Messina, Robert J. Tracy Apr 2012

Bulk Rock Composition And Geochemistry Of Olivine-Hosted Melt Inclusions In The Grey Porri Tuff And Selected Lavas Of The Monte Dei Porri Volcano, Salina, Aeolian Islands, Southern Italy., Angela L. Doherty, Robert J. Bodnar, Benedetto De Vivo, Wendy A. Bohrson, Harvey E. Belkin, Antonia Messina, Robert J. Tracy

All Faculty Scholarship for the College of the Sciences

The Aeolian Islands are an arcuate chain of submarine seamounts and volcanic islands, lying just north of Sicily in southern Italy. The second largest of the islands, Salina, exhibits a wide range of compositional variation in its erupted products, from basaltic lavas to rhyolitic pumice. The Monte dei Porri eruptions occurred between 60 ka and 30 ka, following a period of approximately 60,000 years of repose. The bulk rock composition of the Monte dei Porri products range from basaltic-andesite scoria to andesitic pumice in the Grey Porri Tuff (GPT), with the Monte dei Porri lavas having basaltic-andesite compositions. The typical …


Stratigraphy, Geochronology And Detrital Zircon Provenance Of Two Silicic Ash Layers At Hagerman Fossil Beds National Monument, Idaho, Susan K. Birnbaum, Brock Lipple Apr 2012

Stratigraphy, Geochronology And Detrital Zircon Provenance Of Two Silicic Ash Layers At Hagerman Fossil Beds National Monument, Idaho, Susan K. Birnbaum, Brock Lipple

College of Arts and Sciences Poster Presentations

Hagerman Fossil Beds National Monument (HAFO) is home to the world-famous Hagerman Horse Quarry. This site gives important insight into Pliocene age paleontology. Absolute ages of this site have been elusive, although researchers have assumed the site to be around 3.2 Ma. This study sought to determine more precise ages for the previously documented Hagerman Horse Quarry and Peters Gulch ash layers at HAFO thereby defining a more specific date for the Hagerman fossil assemblage, and to describe and interpret their sedimentary horizons. Detailed stratigraphic columns were created to describe sedimentary layers and establish marker beds. The sedimentology and stratigraphy …


Quantifying Pedogenic Carbon Content Within The Boise River Terraces Using Pressurized Calcimetry, Dawn Jarrels, Annika Quick, Jennifer L. Pierce Apr 2012

Quantifying Pedogenic Carbon Content Within The Boise River Terraces Using Pressurized Calcimetry, Dawn Jarrels, Annika Quick, Jennifer L. Pierce

College of Arts and Sciences Poster Presentations

Soil carbon is the third largest carbon pool within the global carbon cycle; however, soil carbon amounts are not well quantified, and exchange rates of soil carbon are not well understood. Soil carbon can be divided into organic carbon and inorganic carbon, where inorganic carbon (pedogenic carbonate) is precipitated during soil formation and accumulates over time in semi-arid and arid environments. Calcic soils within the semiarid regions of the Boise Valley result from active pedogenic accumulation of secondary CaCO3 resulting in prominent 'caliche' layers in soils formed on many of the Boise River terraces. The larger goals of this …


Tree Ring Dating Of Logs From Woodville Plantation, Bridgeville, Pa Apr 2012

Tree Ring Dating Of Logs From Woodville Plantation, Bridgeville, Pa

Historic Structures

Dating historical structures in Pennsylvania using dendrochronology. The Historical Structures collection consists of reports that are the result of dendochronological analysis of timbers from structures in Pennsylvania and Ohio. Contributors: Aughenbaugh, Kelly; Mennett, Colin; Wiesenberg, Nicholas; Wiles, Greg


Paleomagnetism Of The Knight Island Ophiolite, Prince William Sound, Alaska, Steven M. Espinosa^, Terry L. Pavlis* Apr 2012

Paleomagnetism Of The Knight Island Ophiolite, Prince William Sound, Alaska, Steven M. Espinosa^, Terry L. Pavlis*

COURI Symposium Abstracts, Spring 2012

No abstract provided.


Plankton Evolution Driven By Paleoceanographic Change: Prediscosphaera From The Mid-Cretaceous In The Western North Atlantic, Kristen L. Mitchell Apr 2012

Plankton Evolution Driven By Paleoceanographic Change: Prediscosphaera From The Mid-Cretaceous In The Western North Atlantic, Kristen L. Mitchell

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Well-preserved nannofossil assemblages in late Albian and Cenomanian hemipelagic sections from Ocean Drilling Program (ODP) Leg 171B preserve a record of the early history and adaptive radiation of the calcareous nannofossil genus Prediscosphaera. There was a significant rise in the abundance of the genus (from an average of 2% in the early late Albian to about 6% in the latest Albian and Cenomanian. This rise, and other shorter term pulses of increased generic abundance, corresponds to black shale deposition episodes. Twelve distinct morphotypes that were derived from the long-ranging Prediscosphera columnata and Prediscosphaera spinosa, are recognized and differentiated …


Petrology Of Proterozoic To Tertiary Rocks In The Southern Burro Mountains, Nm: Insights Into Mazatzal To Basin And Range Magmatism And Tectonics, Theda Strickler Apr 2012

Petrology Of Proterozoic To Tertiary Rocks In The Southern Burro Mountains, Nm: Insights Into Mazatzal To Basin And Range Magmatism And Tectonics, Theda Strickler

Undergraduate Research Conference

Analysis of thin sections from the Wind Mountain quadrangle, Burro Mountains, NM, near the Tyrone copper mine, reveals a complex geologic history. Rock samples collected in the study area were cut using a rock saw and thin sections were prepared and analyzed to determine mineral content and fabric patterns. The oldest rocks in the study area are strongly metamorphosed and locally mylonitized Proterozoic quartzofeldspathic gneisses and amphibolites of Mazatzal affinity. Mineralogical indications of shearing correlate with shear zones observed during field mapping in the area. Another set of samples are of younger Proterozoic granites and metagranites that intruded the country …


U/Pb Detrital Zircon Study Of The Upper Cretaceous To Miocene Strata Of Kodiak Island, Alaska, Sarah J. Olivas^, Cameron Davidson, John I. Garver, Diane I. Doser*, Hannah Hilbert-Wolf Apr 2012

U/Pb Detrital Zircon Study Of The Upper Cretaceous To Miocene Strata Of Kodiak Island, Alaska, Sarah J. Olivas^, Cameron Davidson, John I. Garver, Diane I. Doser*, Hannah Hilbert-Wolf

COURI Symposium Abstracts, Spring 2012

No abstract provided.


Tidally Driven Coulomb Failure Along Europa's Agenor Linea, Marissa Cameron^, Amanda Nahm, Robert Pappalardo, Bridget Smith-Konter* Apr 2012

Tidally Driven Coulomb Failure Along Europa's Agenor Linea, Marissa Cameron^, Amanda Nahm, Robert Pappalardo, Bridget Smith-Konter*

COURI Symposium Abstracts, Spring 2012

No abstract provided.


Temporal And Spatial Analysis Of Monogenetic Volcanic Fields, Koji Kiyosugi Apr 2012

Temporal And Spatial Analysis Of Monogenetic Volcanic Fields, Koji Kiyosugi

USF Tampa Graduate Theses and Dissertations

Achieving an understanding of the nature of monogenetic volcanic fields depends on identification of the spatial and temporal patterns of volcanism in these fields, and their relationships to structures mapped in the shallow crust and inferred in the deep crust and mantle through interpretation of geochemical, radiometric and geophysical data.

We investigate the spatial and temporal distributions of volcanism in the Abu Monogenetic Volcano Group, Southwest Japan. E-W elongated volcano distribution, which is identified by a nonparametric kernel method, is found to be consistent with the spatial extent of P-wave velocity anomalies in the lower crust and upper mantle, supporting …


Geologic Mapping Of The South Tibetan Detachment System In Western Bhutan Using Aster Multispectral Data, Adam H. Nazarian ^, Jose M. Hurtado Jr.* Apr 2012

Geologic Mapping Of The South Tibetan Detachment System In Western Bhutan Using Aster Multispectral Data, Adam H. Nazarian ^, Jose M. Hurtado Jr.*

COURI Symposium Abstracts, Spring 2012

Remotely sensed data is a powerful tool for studying geology in areas where traditional field geology proves costly or difficult. This study focuses on geologic mapping of the South Tibetan Detachment System (STDS) in the area where Bhutan, India, and China meet. Having improved geologic maps is important as background information for better understanding the evolution and structure of the regional geology. Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) multispectral imagery was used to differentiate the low-grade metamorphosed Tethyan Sedimentary Sequence (TSS) of the hanging wall from the mid- to high-grade metamorphosed Greater Himalayan Sequence (GHS) of the footwall. …


Reservoir Potential Of Sands Formed In Glaciomarine Environments: An Analog Study Based On Cenozoic Examples From Mcmurdo Sound, Antarctica, Christopher R. Fielding, Brian A. Blackstone, Tracy D. Frank, Zi Gui Apr 2012

Reservoir Potential Of Sands Formed In Glaciomarine Environments: An Analog Study Based On Cenozoic Examples From Mcmurdo Sound, Antarctica, Christopher R. Fielding, Brian A. Blackstone, Tracy D. Frank, Zi Gui

Department of Earth and Atmospheric Sciences: Faculty Publications

This paper provides documentation of unexpectedly high-reservoir-quality glaciomarine sands found in the Cenozoic succession beneath McMurdo Sound, Antarctica, as an analogue study for evaluations of hydrocarbon prospectivity in basins elsewhere. The Oligocene to Lower Miocene succession of the Victoria Land Basin, an extant portion of the West Antarctic Rift System, comprises diamictites, mudrocks, and sandstones with minor conglomerates. These lithologies are arranged in repetitive stacking patterns (cycles), interpreted to record repeated advance and retreat of glaciers into and out of the basin, with attendant eustatic and isostatic effects. Phases of ice retreat within the cycles comprise an array of mudrocks, …


Evaluating The Effects Of Lithofacies And Thin Shales On The Lateral Distribution Of Hydrothermal Dolomite Reservoirs In The Michigan Basin, Peter J. Feutz Apr 2012

Evaluating The Effects Of Lithofacies And Thin Shales On The Lateral Distribution Of Hydrothermal Dolomite Reservoirs In The Michigan Basin, Peter J. Feutz

Masters Theses

The southern Michigan Basin contains numerous hydrothermal dolomite hydrocarbon fields, including the giant Albion-Scipio Field. The fields typically encompass narrow zones of faulting and fracturing which have been altered from a tight host limestone into a more porous and permeable dolomite by upward-moving hydrothermal fluids. Alternating layers of dolomite that spread laterally away from the main vertical fault conduits imply that structure alone may not define the resulting reservoir architectures within the region. A detailed analysis of primary depositional facies and thin shale seams suggests that secondary stratigraphic controls play a significant role in the development of reservoir rock within …


Wilson Cycles, Tectonic Inheritance, And Rifting Of The North American Gulf Of Mexico Continental Margin, Audrey D. Huerta, Dennis L. Harry Apr 2012

Wilson Cycles, Tectonic Inheritance, And Rifting Of The North American Gulf Of Mexico Continental Margin, Audrey D. Huerta, Dennis L. Harry

Geological Sciences Faculty Scholarship

The tectonic evolution of the North American Gulf of Mexico continental margin is characterized by two Wilson cycles, i.e., repeated episodes of opening and closing of ocean basins along the same structural trend. This evolution includes (1) the Precambrian Grenville orogeny; (2) formation of a rift-transform margin during late Precambrian opening of the Iapetus Ocean; (3) the late Paleozoic Ouachita orogeny during assembly of Pangea; and (4) Mesozoic rifting during opening of the Gulf of Mexico. Unlike the Atlantic margins, where Wilson cycles were first recognized, breakup in the Gulf of Mexico did not initially focus within the orogen, but …


Spectral Analysis Of Ground Magnetic Data In Magadi Area, Southern Kenya Rift, Jg Githiri, Jp Patel, Jo Barongo, Pk Karanja Mar 2012

Spectral Analysis Of Ground Magnetic Data In Magadi Area, Southern Kenya Rift, Jg Githiri, Jp Patel, Jo Barongo, Pk Karanja

Tanzania Journal of Science

The area surrounding Lake Magadi in the southern Kenya rift is characterized by hot springs that issue from fractures distributed along the shores of the lake. Presence of earthquake swarms that cluster in northern margin of Lake Magadi strongly indicate magmatic activity in the area. This study was done as a follow-up to investigate depth to the heat source possibly causing high seismic activity and high heat flow in the area. A ground magnetic survey was conducted to investigate geothermal potential of the area and a magnetic anomaly contour map prepared. Spectral analysis involving determining power spectrum was applied to …


Mg-Rich Metabasalts From The Southern Musoma –Mara Greenstone Belt: Possible Evidence For Mantle Plume Activity In The Tanzania Craton?, S Manya Mar 2012

Mg-Rich Metabasalts From The Southern Musoma –Mara Greenstone Belt: Possible Evidence For Mantle Plume Activity In The Tanzania Craton?, S Manya

Tanzania Journal of Science

Mg-rich metabasalts from the Simba Sirori to Majimoto segment of the southern Musoma-Mara greenstone belt are the most magnesian lavas reported in the Archaean Tanzania Craton. The lavas yielded a Sm-Nd isochron age of 2768 ± 38 Ma (MSWD = 1.2) and corresponding !Nd(2.7 Ga) values in the range of + 0.66 to + 2.81. The lavas exhibit high MgO contents of up to 16 wt %, Cr (140 – 1590 ppm), Ni (80 – 510 ppm), values which are higher than those of primitive NMORB, but are comparable with those of Archaean komatiitic basalts and modern oceanic plateau basalts. …


Feeding Habitats Of The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi, In The Suwannee And Yellow Rivers, Florida, As Identified By Multiple Stable Isotope Analyses, Kenneth J. Sulak, J. J. Berg, M. Randall Mar 2012

Feeding Habitats Of The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi, In The Suwannee And Yellow Rivers, Florida, As Identified By Multiple Stable Isotope Analyses, Kenneth J. Sulak, J. J. Berg, M. Randall

United States Geological Survey: Staff Publications

Stable 13C, 15N, and 34S isotopes were analyzed to define the feeding habitats of Acipenser oxyrinchus desotoi in the Suwannee and Yellow River populations. For the majority (93.9%) of Suwannee sub adults and adults, 13C and 34S signatures indicate use of nearshore marine waters as primary winter feeding habitat, probably due to the limiting size of the Suwannee Sound estuary. In the Yellow River population, 13C isotope signatures indicate that adults remain primarily within Pensacola Bay estuary to feed in winter, rather than immigrating to the open Gulf of Mexico. A minor Suwannee River subset (6% of …


Heterogeneous Detection Probabilities For Imperiled Missouri River Fishes: Implications For Large-River Monitoring Programs, Joshua T. Schloesser, Craig P. Paukert, Wyatt J. Doyle, Tracy D. Hill, Kirk D. Steffensen, Vince H. Travnichek Mar 2012

Heterogeneous Detection Probabilities For Imperiled Missouri River Fishes: Implications For Large-River Monitoring Programs, Joshua T. Schloesser, Craig P. Paukert, Wyatt J. Doyle, Tracy D. Hill, Kirk D. Steffensen, Vince H. Travnichek

United States Geological Survey: Staff Publications

Occupancy modeling was used to determine (1) if detection probabilities (p) for 7 regionally imperiled Missouri River fishes (Scaphirhynchus albus, Scaphirhynchus platorynchus, Cycleptus elongatus, Sander canadensis, Macrhybopsis aestivalis, Macrhybopsis gelida, and Macrhybopsis meeki) differed among gear types (i.e. stationary gill nets, drifted trammel nets, and otter trawls), and (2) how detection probabilities were affected by habitat (i.e. pool, bar, and open water), longitudinal position (five 189 to 367 rkm long segments), sampling year (2003 to 2006), and season (July 1 to October 30 and October 31 to June 30). Adult, large-bodied fishes were …


Habitat And Prey Availability Attributes Associated With Juvenile And Early Adult Pallid Sturgeon Occurrence In The Missouri River, Usa, Bryan D. Spindler, Steven R. Chipps, Robert A. Klumb, Brian D. S. Graeb, Michael C. Wimberly Mar 2012

Habitat And Prey Availability Attributes Associated With Juvenile And Early Adult Pallid Sturgeon Occurrence In The Missouri River, Usa, Bryan D. Spindler, Steven R. Chipps, Robert A. Klumb, Brian D. S. Graeb, Michael C. Wimberly

United States Geological Survey: Staff Publications

The pallid sturgeon Scaphirhynchus albus is a federally endangered species native to the Missouri and lower Mississippi Rivers, USA. As part of recovery efforts, over 360 000 pallid sturgeon have been stocked into the Missouri River since 1994, and a standardized, long-term monitoring program was initiated in 2003. Understanding the distribution and habitat requirements of juvenile and early adult pallid sturgeon (fork length <720 mm, age <10 yr) is an important goal of the monitoring and recovery programs. In this study, we collected information on habitat characteristics and prey availability from the upper Missouri River along the Nebraska-South Dakota border and compared these attributes between capture (present) and non-capture (absent) locations (N = 59). To evaluate the relative influence of habitat and prey availability on pallid sturgeon occurrence, we examined several candidate models using an informationtheoretic approach. A prey availability model had the most support and included site-specific information on Diptera and Ephemeroptera abundance. A habitat-based model showed that juveniles and early adults were found in relatively deeper water and avoided areas where bottom velocities were greater than 1.2 m s−1. Although not as well supported as the prey-effects model (evidence ratio = 6.4), habitat features also provided a plausible model for predicting occurrence. The models developed here could be used to evaluate pallid sturgeon habitat potential in the Missouri River basin and help guide future monitoring and conservation management of this endangered species.


Projecting Changes In Extreme Precipitation In The Midwestern United States Using North American Regional Climate Change Assessment Program (Narccap) Regional Climate Models, Shuang-Ye Wu Mar 2012

Projecting Changes In Extreme Precipitation In The Midwestern United States Using North American Regional Climate Change Assessment Program (Narccap) Regional Climate Models, Shuang-Ye Wu

Department of Earth, Environment and Sustainability Faculty Publications

Based on the physics of global circulation, many expect an enhanced greenhouse effect to lead to a more active hydrological cycle with more precipitation on average (Hennessy et al. 1997). This expected increase has been found in observations (Zhang et al. 2007) and has also been suggested by climate models, although these models are not consistent with respect to the spatial and temporal variability about this change. An increase in mean precipitation depth, assuming no change in the shape of the frequency distribution, would imply an increased frequency of heavy-precipitation events. However, some studies (Hennessy et al. 1997, Allen and …


Mafic Alkaline Magmatism In The East Tintic Mountains, West-Central Utah: Implications For A Late Oligocene Transition From Subduction To Extension, Tara Laine Allen Mar 2012

Mafic Alkaline Magmatism In The East Tintic Mountains, West-Central Utah: Implications For A Late Oligocene Transition From Subduction To Extension, Tara Laine Allen

Theses and Dissertations

Voluminous Eocene to Oligocene intermediate to silicic volcanic rocks related to subduction erupted throughout the Great Basin and were supplanted by bimodal eruptions of basalt and rhyolite related to extension in the Miocene. Locally, in the northern East Tintic Mountains of central Utah, this important transition is marked by a distinctive package of mafic alkaline magmas that reveal important details about the nature of this fundamental change. A late Oligocene anorthoclase-bearing shoshonite lava in the Boulter Peak quadrangle contains megacrysts of anorthoclase, with phenocrysts of olivine, clinopyroxene, magnesiohastingsite, magnetite, and apatite. The anorthoclase grains occur as glomerocrysts with irregular, resorbed …


Geodetic Constraints On San Francisco Bay Area Fault Slip Rates And Potential Seismogenic Asperities On The Partially Creeping Hayward Fault, Eileen L. Evans, John P. Loveless, Brendan J. Meade Mar 2012

Geodetic Constraints On San Francisco Bay Area Fault Slip Rates And Potential Seismogenic Asperities On The Partially Creeping Hayward Fault, Eileen L. Evans, John P. Loveless, Brendan J. Meade

Geosciences: Faculty Publications

The Hayward fault in the San Francisco Bay Area (SFBA) is sometimes considered unusual among continental faults for exhibiting significant aseismic creep during the interseismic phase of the seismic cycle while also generating sufficient elastic strain to produce major earthquakes. Imaging the spatial variation in interseismic fault creep on the Hayward fault is complicated because of the interseismic strain accumulation associated with nearby faults in the SFBA, where the relative motion between the Pacific plate and the Sierra block is partitioned across closely spaced subparallel faults. To estimate spatially variable creep on the Hayward fault, we interpret geodetic observations with …


Response Of A Carbonate Platform To The Cenomanian-Turonian Drowning And Oae 2: A Case Study From The Adriatic Platform (Dalmatia, Croatia), Tvrtko Korbar, B. Glumac, Blanka Cvetko Tesovic, Sarah B. Cadieux Mar 2012

Response Of A Carbonate Platform To The Cenomanian-Turonian Drowning And Oae 2: A Case Study From The Adriatic Platform (Dalmatia, Croatia), Tvrtko Korbar, B. Glumac, Blanka Cvetko Tesovic, Sarah B. Cadieux

Geosciences: Faculty Publications

Global perturbations during the Cenomanian–Turonian boundary (CTB) interval and the Oceanic Anoxic Event 2 (OAE 2) represent one of the most extensively studied past environmental changes. To explore the response of various carbonate-platform depositional systems to such major environmental perturbations, strata of the intra-Tethyan Adriatic carbonate platform (sensu stricto) from the island of Bracˇ (Adriatic Sea, Croatia) provide excellent exposures and a previously well-established Upper Cretaceous lithostratigraphic framework. Within this context, this study integrated lithostratigraphy, biostratigraphy, and chemostratigraphy to describe a drowned-platform succession underlain and overlain by peritidal carbonates. Carbon-isotope stratigraphy of this succession revealed a shift towards positive d13C …


Real-Time Change And Damage Detection Of Landslides And Other Earth Movements Threatening Public Infrastructure, Michael J. Olsen, Shawn Butcher, Evon P. Silvia Mar 2012

Real-Time Change And Damage Detection Of Landslides And Other Earth Movements Threatening Public Infrastructure, Michael J. Olsen, Shawn Butcher, Evon P. Silvia

TREC Final Reports

Geologic hazards such as coastal erosion, landslides, seismic loading, etc. constantly threaten public highway construction and maintenance. Repeat surveys using terrestrial laser scanning (TLS, ground-based LiDAR) enable rapid 3D data acquisition to map, see, analyze, and understand the processes generating such problems. Previously, change detection and analysis between scan surveys was conducted during post-processing upon return to the office, instead of while collecting data in the field. Change detection in the field improves the effectiveness and efficiency of the field investigation. We have developed a new algorithm that quickly geo-references scans upon field acquisition and simultaneously performs change detection by …


Particle Transport Over Rough Hillslope Surfaces By Dry Ravel: Experiments And Simulations With Implications For Nonlocal Sediment Flux, Emmanuel Gabet, Morgan Mendoza Feb 2012

Particle Transport Over Rough Hillslope Surfaces By Dry Ravel: Experiments And Simulations With Implications For Nonlocal Sediment Flux, Emmanuel Gabet, Morgan Mendoza

Faculty Publications

Past studies of hillslope evolution have typically assumed that soil creep processes are governed by a linear relationship between local hillslope angle and transport distance. The assumption of “linear diffusion” has fallen out of favor because, when coupled with an expression of mass continuity, it yields unrealistic hillslope profiles. As a consequence, a better understanding of the mechanics of sediment transport is needed. Here we report results from a series of flume experiments performed to investigate sediment transport by dry ravel, a common soil creep process in arid and semiarid environments. We find that, at gentle slopes, transport distances follow …