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Articles 151 - 180 of 453
Full-Text Articles in Earth Sciences
From The Rim To The River: The Geomorphology Of Debris Flows In The Green River Canyons Of Dinosaur National Monument, Colorado And Utah, Isaac J. Larsen
From The Rim To The River: The Geomorphology Of Debris Flows In The Green River Canyons Of Dinosaur National Monument, Colorado And Utah, Isaac J. Larsen
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Green River canyons of the eastern Uinta Mountains have experienced a 5-year period of high debris flow activity. Catchment factors were studied in watersheds and on debris fans with recent debris flows, leading to the development of a conceptual framework of the hillslope and debris flow processes that deliver sediment to the Green River. Two recent fan deposits were monitored to determine the magnitude and processes of reworking that occur during mainstem floods of varying magnitude.
The dominant debris flow initiation mechanism, termed the firehose effect, occurs when overland flow generated on bedrock slopes cascades down steep cliffs and …
Using Geographic Information Systems And Remote Sensing To Analyze Fire Likelihood Areas At The Regional Scale In The Western United States, Russell W. Reading
Using Geographic Information Systems And Remote Sensing To Analyze Fire Likelihood Areas At The Regional Scale In The Western United States, Russell W. Reading
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Geographic Information Systems (GIS) are increasingly used to examine fire activity. This study uses GIS to determine fire likelihood probabilities at an intermediate scale ( I-kilometer) on a daily basis given readily available data. Layers used for the analysis included slope, aspect, elevation, fuel type, proximity to existing fires, maximum temperature, minimum temperature, relative humidity, average vapor pressure deficit, precipitation, 1-hour fuel moisture, and 10-hour fuel moisture.
There were three objectives of this study: 1. Establish a correlation between burn perimeters and readily available topographic and environmental data, and map the spatial distribution of these as fire likelihood areas; 2. …
Evaluation Of Chela Formation In Kambala-Livuite Area, Southern Block 0, Cabinda, Angola, Alba B. Bias Dos Santos
Evaluation Of Chela Formation In Kambala-Livuite Area, Southern Block 0, Cabinda, Angola, Alba B. Bias Dos Santos
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The abundance of good reservoir and source rocks offshore Cabinda, Angola, makes the area an attractive and successful hydrocarbon province. Block 0, offshore Cabinda, lies in the Lower Congo basin along the western coast of Africa. The stratigraphy of Block 0 consists of two major oil-rich sequences: the rift sequence (primarily lacustrine) and the post-rift sequence (primarily marine). These are separated by a thick section of evaporites, and thus are referred to as the pre-salt sequence and post-salt sequence, respectively.
The Chela Formation, mid-Aptian in age, was deposited before the salt. It consists of sandstones and conglomerates locally interbedded with …
Mitigation, Monitoring, And Geomorphology Related To Gully Erosion Of Archaeological Sites In Grand Canyon, Paul A. Petersen
Mitigation, Monitoring, And Geomorphology Related To Gully Erosion Of Archaeological Sites In Grand Canyon, Paul A. Petersen
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Gully erosion has been damaging archaeological sites in Grand Canyon during the last several decades, and there is a need to protect these features through mitigation, monitoring, and better geomorphic understanding. The purpose of this study was to assess the effectiveness of erosion-control structures, determine the accuracy and utility of aerial photogrammetry for monitoring gullies, and understand the geomorphology of the erosion. We performed total-station surveys and other data collection during February and October, 2002, at nine study sites in eastern and western Grand Canyon.
Erosion-control structures are more prone to be damaged by flow when they are placed in …
Quaternary Geology And Landscape Evolution Of Eastern Grand Canyon, Arizona, Matt D. Anders
Quaternary Geology And Landscape Evolution Of Eastern Grand Canyon, Arizona, Matt D. Anders
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Tectonics and drainage evolution are controlling overall landscape incision in eastern Grand Canyon. Superimposed on downcutting are dynamic responses of hillslopes, tributary streams, and the Colorado River to glacial-interglacial climate cycles. Five tributary stream fill terraces have been identified, and luminescence dating indicates aggradation was occurring 50- 34 ka {S3), 12-7 ka (S2), and 5-3.5 ka (S1). Seven Colorado River fill terraces have been identified, and luminescence and U-series dating indicate deposition was occurring 343-322 ka (M5), 151-118 ka (M4), and 71-64 ka (M3).
Aggradation by the Colorado River in eastern Grand Canyon begins during glacial advances and continues into …
Simulation Of Groundwater Flow In Cache Valley, Utah And Idaho, Barry Myers
Simulation Of Groundwater Flow In Cache Valley, Utah And Idaho, Barry Myers
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
A groundwater model of Cache Valley was created using MODFLOW. Steady-state calibration of the model demonstrated that recharge to the lower confined aquifer may occur along the margin of the valley that borders the Wellsville Mountains and the Bear River Range. Steady-state calibration also showed that discharge from the unconfined aquifer may occur along the eastern and western margins of the valley in both the Utah and the Idaho portions of the valley.
Two simulations were run with increased pumping of 3 5 cubic feet per second (1 cubic meter per second) from the principal aquifer. The first simulation was …
Characteristics, Evolution, And Lateral Variation Of Lower Cretaceous Supradetachment Basins In The Daqing Shan, Inner Mongolia, China, Adrian K. Berry
Characteristics, Evolution, And Lateral Variation Of Lower Cretaceous Supradetachment Basins In The Daqing Shan, Inner Mongolia, China, Adrian K. Berry
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Lower Cretaceous basins associated with the Hohhot detachment in the Daqing Shan of Inner Mongolia, China, allow us to better understand the tectonic evolution of extensional basins formed in association with detachment faulting and metamorphic core complex formation. The six basins, informally named N1, N2, S1, S2, S3, and S4, are located in different structural settings, or depozones, throughout the detachment-metamorphic core complex setting, and although all basins are consistent with previously proposed models for supradetachment basin sedimentation, second-order variability in sedimentary style is exerted by these distinct structural settings. The basins are composed of coarse, predominantly footwall derived, conglomerate …
Geology Of The Deseret Peak East 7.5' Quadrangle, Tooele County, Utah, And Impacts For Hydrology Of The Region, Torrey J. Copfer
Geology Of The Deseret Peak East 7.5' Quadrangle, Tooele County, Utah, And Impacts For Hydrology Of The Region, Torrey J. Copfer
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Detailed geologic mapping of the Deseret Peak East 7.5' Quadrangle yields new interpretations regarding the stratigraphy of the Oquirrh Basin, fault and fold geometry, and structural evolution of the region. The Stansbury Range consists of the north-south-trending Deseret anticline. Basal Mississippian units rest unconformably on Cambrian beds in the central part of the range. Paleozoic uplift, Mesozoic contraction, and Cenozoic extension have created a series of broad folds, large thrust faults, and several normal faults.
The area is dominated by bedrock springs, with the presence of abundant and thick Quaternary deposits unrelated to Pleistocene glaciation, burying drainages, and mantling hillslopes. …
One-Dimensional Modeling Of Bromide Tracer And Trichloroethylene Transport Based On Laboratory Experiments In Vertical Soil Columns, Keri L. Murch
One-Dimensional Modeling Of Bromide Tracer And Trichloroethylene Transport Based On Laboratory Experiments In Vertical Soil Columns, Keri L. Murch
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Enhanced biodegradation using carbon donor and microbial addition is being considered as a possible remediation technique for a trichloroethylene (TCE) contaminated area in Sunset, Utah, west of the source area on Hill Air Force Base. As a precursor to any in situ remediation attempts, several laboratory treatability experiments are being conducted, including the construction of microcosms and flow-through columns. Nine large-scale flow-through columns were built using site groundwater and aquifer material. Bromide tracer tests were conducted to establish and understand the hydraulic conditions within the columns prior to the commencement of the TCE biodegradation experiments. Four predictive models were created …
Validation Of A Radiometric Normalization Procedure For Satellite-Derived Imagery Within A Change Detection Framework, Karin E. Callahan
Validation Of A Radiometric Normalization Procedure For Satellite-Derived Imagery Within A Change Detection Framework, Karin E. Callahan
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Detecting changes in land cover through time using remotely sensed imagery is a powerful application that has seen increased use as imagery has become more widely available and inexpensive. Before a time series of remotely sensed imagery can be used for change detection, images must first be standardized for effects outside of real surface change. This thesis established a validation protocol to evaluate the effectiveness of an automated technique for normalizing temporally separate but spatially coincident imagery. Using the concept of pseudo-invariant features between master-slave image pairs, spatially coincident dark and bright points are identified from images and a regression …
The Middle Cambrian Wheeler Formation: Sequence Stratigraphy And Geochemistry Across A Ramp-To-Basin Transition, Elizabeth S. Langenburg
The Middle Cambrian Wheeler Formation: Sequence Stratigraphy And Geochemistry Across A Ramp-To-Basin Transition, Elizabeth S. Langenburg
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Middle Cambrian Wheeler Formation is interpreted as having been deposited in the shallow ramp and deeper basin environments of the House Range embayment (HRE), presumably, during a single third-order sequence. In the Drum Mountains, the Wheeler Formation (295 m thick) is dominated by proximal and distal ramp deposits; at Marjum Pass, the Wheeler Formation (190m thick) is dominated by basinal shale deposits. The Wheeler Formation contains only one biozone marker; the first appearance of Ptyhagnostus atavus. Lack of other chronostratigraphic markers and distinctive stratal patterns in the basinal facies makes correlation along this ramp-to-basin transect difficult. Therefore, carbon-isotope …
Evolution Of A Miocene-Pliocene Low-Angle Normal-Fault System In The Southern Bannock Range, Southeast Idaho, Stephanie M. Carney
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 …
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
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 …
Stratigraphy And Paleoecology Of The Morrison Formation, Como Bluff, Wyoming, Melissa V. Connely
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 …
A Macroterrain Landtype Association Classification Model For The Great Basin, Frank L. Dougher
A Macroterrain Landtype Association Classification Model For The Great Basin, Frank L. Dougher
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Three Macroterrain Landtype Association classification models were developed to stratify and categorize Utah's West Desert. These models approached terrain segmentation using an energy-flow paradigm from erosional to transitional to depositional landscape. One model was developed as a slope-backed deterministic model that used slope-threshold limits to discriminate between Landtype Associations. A second model was developed as a stochastic, training-data driven supervised classification, using comparative t-values to classify the landscape to the most similar landtype class. The third model was a probabilistic algorithm, which classified the landscape to the most probable class based on multiple iterations of the stochastic model. These …
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 …
Geometry And Physical Properties Of The Chelungpu Fault, Taiwan, And Their Effect On Fault Rupture, Richard V. Heermance
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 …
Structural And Kinematic Evolution Of Eocene-Oligocene Grasshopper Extensional Basin, Southwest Montana, Julie C. Kickham
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 …
The Stratigraphic, Sedimentologic, And Paleogeographic Evolution Of The Eocene- Oligocene Grasshopper Extensional Basin, Southwest Montana, Joseph P. Matoush
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 …
Sedimentology, Facies Architecture, And Reservoir Characterization Of Lacustrine Rocks, Eocene Green River And Colton Formations, Uinta Basin, Utah, Andrew W. Taylor
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 …
Application Of Biophysical Data To An Unsupervised Classification To Map Ecoregional Boundaries In The Desert Southwest, Paxton R. Mcclurg
Application Of Biophysical Data To An Unsupervised Classification To Map Ecoregional Boundaries In The Desert Southwest, Paxton R. Mcclurg
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
An unsupervised classification was applied to continuous biophysical variables in an attempt to delineate ecoregional boundaries in the desert southwest. Output was then compared with ecoregions delineated by the Natural Resources Conservation Service (NRCS), the Environmental Protection Agency (EPA), and the Forest Service at the national level. An attempt was made to use the same biophysical variables for input into the unsupervised classification as was emphasized by the various agencies with their ecoregional classifications at the desert level. Major constraints included data availability at such a large study area, data resolution, and data that were continuous. This eliminated categorical data …
Post-Tillage Dynamics Of Soil Structural And Hydraulic Properties Induced By Capillary Forces And External Loading, Teamrat Afewerki Ghezzehei
Post-Tillage Dynamics Of Soil Structural And Hydraulic Properties Induced By Capillary Forces And External Loading, Teamrat Afewerki Ghezzehei
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Tillage modifies the soil structure to create conditions favorable for plant growth. However, the resulting loose structure is susceptible to collapse by internal capillary forces and external compactive stresses with concurrent changes in soil hydraulic properties. Presently, limited understanding of these complex processes often leads to consideration of the soil plow-layer as a static porous medium. The objective of this dissertation was to develop physically based modeling of soil structural dynamics at the pore scale, based on soil mechanical and rheological properties. The basic geometrical framework of the models was based on regular packing of monosized spherical aggregates forming unit-cells. …
Controls On Channel Organization And Morphology In A Glaciated Basin In The Uinta Mountains, Utah, Betty E. Paepke
Controls On Channel Organization And Morphology In A Glaciated Basin In The Uinta Mountains, Utah, Betty E. Paepke
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The organization and morphology of Middle Fork Sheep Creek and South Fork Sheep Creek, two mountain streams in the upper Sheep Creek basin, are controlled by the spatial distribution of glacial moraines. Both channels are organized into a reoccurring sequence of steep-gradient reaches changing downstream to low-gradient reaches. Steep-gradient reaches are located where the channels flow through moraine s. Low-gradient reaches are located in meadows downstream of the steep-gradient reaches and immediately upstream of the next moraine. Knickpoints in the longitudinal profiles of both streams coincide with the location of moraines.
Large boulder s, beyond the size transportable by the …
Effects Of High Ammonium/Nitrate Ratios On Nitrification And Growth Of Wheat In Hydroponics, Dawn J. Muhlestein
Effects Of High Ammonium/Nitrate Ratios On Nitrification And Growth Of Wheat In Hydroponics, Dawn J. Muhlestein
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Nitrogen is the only plant nutrient taken up as both a cation (NH4+) and anion (NO3-). Nitrate is considered the "safe" form of N and NH/ is generally thought to be toxic, especially at high levels. High NH4+/NO3- ratios are thought to be toxic because they result in a rhizosphere pH low enough to damage root membranes, induced cation deficiencies, and build-up of NH3 caused by delayed NH/ assimilation. These factors can be minimized in hydroponic culture. The objective of these studies was to quantify the effects of high …
Structural And Geochemical Analyses Of Disseminated-Gold Deposits, Bald Mountain-Alligator Ridge District, Nevada: Insights Into Fault-Zone Architecture And Its Effect On Mineralization, K. Jill Hammond
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Structural and geochemical analyses of the Top and Casino deposits, Bald Mountain-Alligator Ridge district, Nevada, were conducted to determine how structures affected gold deposition in Carlin-type deposit s. We also examined how permeability changed over time in a fault that cuts siltstone-dominated sedimentary rocks. The association of gold and related arsenic with faults at the margins of a Jurassic pluton and sedimentary rocks suggests that ore fluids migrated along faults and fracture s. Permeability of the faults changed over time within the Casino deposit, where the ore-controlling fault was a distributed conduit in the early stages of mineralization but a …
The Efficacy Of Plant Residue Degradation Products On Phosphorus, Iron, Iodine, And Fluorine Bioavailability To Plants, Cheryl L. Mackowiak
The Efficacy Of Plant Residue Degradation Products On Phosphorus, Iron, Iodine, And Fluorine Bioavailability To Plants, Cheryl L. Mackowiak
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Plant and animal wastes degrade in soils to form relatively stable humified compounds, which form ion complexes that affect the bioavailability of elements in the soil solution. Hydroponic studies with wheat and rice were conducted to characterize the effect of humic acid (HA) on phosphorus (P), iron (Fe), fluorine (F), and iodine (I) bioavailability. Ferrihydrite [Fe(OH)3] precipitation was greater on root surfaces without HA or synthetic chelates. Oxides such as ferrihydrite strongly adsorb P and provide exchange sites for metals. HA reduced this precipitate and increased P and Fe uptake.
Humic acid had no effect on F toxicity …
Structural Analysis And A Kink Band Model For The Formation Of The Gemini Fault Zone, An Exhumed Left-Lateral Strike Slip Fault Zone In The Central Sierra Nevada, California, Matthew A. Pachell
Structural Analysis And A Kink Band Model For The Formation Of The Gemini Fault Zone, An Exhumed Left-Lateral Strike Slip Fault Zone In The Central Sierra Nevada, California, Matthew A. Pachell
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The structure and regional tectonic setting of an exhumed, 9.3-km long, left-lateral strike-slip fault zone eludicates processes of growth, linkage, and termination for strike-slip fault zones in granitic rocks. The Gemini fault zone is composed of three steeply dipping, southwest-striking, noncoplanar segments that nucleated and grew along preexisting joints. The fault zone has a maximum slip of 131 m and is an example of a segmented, hard-linked fault zone in which geometrical complexities of the faults and compositional variations of protolith and host rock resulted in nonuniform slip orientations, complex interactions at fault segments, and an asymmetric slip-distance profile. Regional …
The Sequence Stratigraphy Of The Middle Cambrian Wheeler Formation In The Drum Mountains Of West Central Utah, Loren P. Schneider
The Sequence Stratigraphy Of The Middle Cambrian Wheeler Formation In The Drum Mountains Of West Central Utah, Loren P. Schneider
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The majority of the Middle Cambrian Wheeler Formation in the Drum Mountains was deposited during a single 3rd order sequence. Superimposed onto this sequence are three indistinct 4th order cycles and twenty distinct 5th order cycles. These higher order cycles were likely deposited within short intervals of geologic time (204 to 405 ky).
The lower sequence boundary zone occurs within the Swasey Formation. The Transgressive Surface is the contact between the Swasey and Wheeler Formations. The Maximum Flooding Surface is located near the top of the lower Wheeler Formation, which also approximates the base of the Ptychagnostus …
Holocene Tephrostratigraphy, Southern Kenai Peninsula, Lower Cook Inlet, Alaska, Kathleen J. Lemke
Holocene Tephrostratigraphy, Southern Kenai Peninsula, Lower Cook Inlet, Alaska, Kathleen J. Lemke
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
This thesis describes the results of a study of 33 tephra layers found within two peat sections near Anchor Point and Homer, Alaska, on the lower Kenai Peninsula. Numerous lower Cook Inlet volcanoes have been active through the Holocene. Tephra layers found at these two sites provide a partial record of their eruptive activity. The hazards that accompany this activity have increased as populations and commercial activities expand and air traffic over the region increases. The tephras analyzed for this study provide an initial geochemical database for the lower Cook Inlet volcanoes. The database is available in electronic format at …
Debris-Flow Activity In Canyon Of Lodore, Colorado: Implications For Debris-Fan Formation And Evolution, Jennifer A. Martin
Debris-Flow Activity In Canyon Of Lodore, Colorado: Implications For Debris-Fan Formation And Evolution, Jennifer A. Martin
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Large-scale characteristics of Ladore Canyon debris fans are dependent upon the bedrock and lithology of the mainstem and tributary canyons. The largest fans occur in the widest section of the mainstem canyon, which typically correlates with the location of large faults. The steepest fans are found at the mouths of tributaries where cliffs are formed by resistant lithologies. Smaller-scale fan characteristics are dependent upon the magnitude and frequency of events from the respective drainage basin, which is controlled primarily by climate. Three distinct deposit ages (oldest, intermediate, youngest) were distinguished on individual fans and were tentatively correlated throughout the canyon …