Tectonics and Structure Commons^™

A Karst Feature Prediction Model For Prince Of Wales Island, Alaska Based On High Resolution Lidar Imagery, Alexander Lyles

Master's Theses or Doctor of Nursing Practice

Investigation into surface karst formation is significant to hazard prediction, hydrogeologic drainage, and land management. Southeast Alaska contains over 600,000 acres of mapped carbonate bedrock, and some of the fastest recorded karst dissolution in the world. The objectives of this study are to develop and compare multiple semi-automated models to map and delineate karst features from bare-earth LiDAR imagery using ArcGIS Desktop 10.7, and to apply a preliminary geostatistical analysis of sinkhole morphometric parameters to highlight potential spatial patterns of karst evolution on Prince of Wales Island, Alaska. A semi-automated approach of mapping karst features provides a dataset that minimizes …

Analyzing Slab Holes In Subduction Zones And Their Impacts Through Numerical Simulations, Taylor M. Arrowood

Theses and Dissertations--Earth and Environmental Sciences

Subduction zones form as higher density oceanic lithosphere is forced beneath an over-riding, lower density, continental or oceanic plate; a process driven by contrasts in buoyancy throughout this system. We seek to explore subduction zones in which the subducting lithosphere is discontinuous after passing through the trench, forming a slab gap. The main research objective is to determine the effect of slab gaps on surface topography in a subduction-related orogen and asthenospheric flow into the mantle wedge using two and three-dimensional numerical mechanical models. We obtain results from 24+ models that suggest a connection between slab gaps/holes and the magnitude …

Advancement Of Full-Vector Variable-Temperature Magnetometry For Rock-Magnetic And Paleointensity Applications, Leonid Surovitskii

Dissertations, Master's Theses and Master's Reports

Data on the variation of the direction and strength of Earth’s ancient magnetic field (absolute paleointensity) provide crucial information into the mechanisms of the geodynamo and the Earth’s thermal history. However, the use of conventional methods and instrumentation for absolute paleointensity determination has been hampered by physicochemical alteration of the samples caused by multiple high-temperature cycles and long experiment durations. The reliability and efficiency of the measurement process can be improved by the measurement of the full remanent magnetization vector simultaneously with the temperature cycling of a sample. Such as approach can also substantially expand the scope of materials available …

Geologic Mapping Along The Benton Spring Fault, Nevada: Dextrally-Offset Tuff-Filled Paleovalleys In The Central Walker Lane, Peter Dubyoski

All Master's Theses

Documenting the spatiotemporal evolution of fault systems along the western margin of North America is a prerequisite for characterizing the forces which drive faulting across the U.S. Cordillera. Within the Cordillera, the Walker Lane, characterized by active intracontinental faults, straddles the western edge of the Basin and Range Province and the eastern edge of the Sierra Nevada. In the Gabbs Valley Range, central Nevada, eastern Central Walker Lane, I combine new mapping, geochronology, and structural studies to document the geometry and timing of dextral fault slip along the Benton Spring fault, an active intracontinental fault. The Benton Spring fault is …

The Effects Of Heterogeneities And Syn-Deformational Partial Melting On Rock Strength Evolution And Melt Migration, Nicole Wagner

Williams Honors College, Honors Research Projects

In nature, the segregation of granitic melts at the source may be controlled by fabric and compositional heterogeneities in the source rock, such as foliation and lineation. To investigate the influence of foliation/lineation orientation and composition on rock strength and melt interconnectivity, I performed a series of experiments on cores of a fine-grained gneiss (Gneiss Minuti) and a fine-grained muscovite-bearing quartzite (Moine Thrust quartzite). These rocks were cored at six primary orientations parallel, 45 degrees, and perpendicular to the foliation and lineation and were deformed at a constant temperature of 900°C, pressure of ~2 GPa, and strain rate of ~10-6/s …

Petrogenesis And Tectonic Implications Of Cordierite-Orthoamphibole Gneisses (Cog) In The Nw Wyoming Province, Brianna K. Crenshaw Ms

Graduate Student Theses, Dissertations, & Professional Papers

Studying cordierite orthoamphibole gneisses (COG) from five different mountain ranges across the Montana Metasedimentary Terrane (MMT) of the Wyoming Province offers a unique opportunity to elucidate the enigmatic origins and petrogenesis of the lithology in addition to gaining a further understanding of Precambrian crustal assembly processes. Geochemical analyses suggest that COG originates from a basalt that underwent metasomatic alteration, likely via seawater, prior to metamorphism. Moreover, COG is considered to represent oceanic crust that was part of the epicontinental sea adjacent to the Wyoming Province before collision with the Medicine Hat Block. Field observations of associated lithologies such as marbles, …

Analysis Of Water Concentration Formed Within Deformed Synthetic Quartz Crystals, Andrew Steward

Williams Honors College, Honors Research Projects

Analyzing the strength of synthetic quartz is essential to understanding the strength of natural milky quartz, which likely controls the strength of Earth’s continental crust. Synthetic quartz is sometimes used for deformation experiments because it has a homogenous water distribution unlike natural milky quartz. The purpose of this study is to determine if annealing synthetic quartz at T = 600°C will convert the water in synthetic quartz to free water, like milky quartz, but with little water loss. Following two annealing experiments at Texas A&M University, I performed four annealing experiments to measure the water content of five synthetic quartz …

Structural Analysis And Interpretation Of Deformation Along The Keweenaw Fault System West Of Lake Gratiot, Keweenaw County, Michigan, Sophie A. Mueller

Dissertations, Master's Theses and Master's Reports

The Keweenaw fault is perhaps the most significant fault associated with the Midcontinent Rift System of the north-central United States. The fault, parallel to the south edge of the rift, has been interpreted as a rift-bounding normal fault that was inverted by subsequent compressional events, thrusting copper-bearing Portage Lake Volcanics (~ 1.1 Ga) over younger Jacobsville Sandstone. Geologic maps and cross sections published in the 1950s by the U. S. Geological Survey depict the fault with a well-defined, single, sinuous trace that is locally associated with smaller branch faults. Cross-sections from that time generally show a simple listric stratal geometry …

Genesis Of Trondhjemite By Low-Pressure Fraction Anatexis Of Hornblende-Gabbro At Alvand Plutonic Complex (Hamedan, Nw Iran): Insights From Geochemical Modelling., Federico Lucci, Adel Saki, Mirmohammad Miri, Ahmad Rabiee, John C. White

EKU Faculty and Staff Scholarship

Amphibole-dominated dehydration melting of gabbro is the primary process responsible for the genesis of adakites, low-K tonalites, modern trondhjemites, and plagiogranites aswell as Archean tonalite-trondhjemite-granodiorite suites that represent the earliest examples of continental crust. Previous literature has mostly focused on the role of Al-rich amphibole during anatexis of a mafic source and many of these studies have investigated this process through experimental melting runs. However, due to experimental boundary conditions, little is known about partial melting of amphibole-bearing mafic rock at temperatures < 800°C for upper crustal conditions (pressure < 500 MPa). Classic and forward thermobarometric modelling suggests that in situ trondhjemite leucosomes, hosted by Cheshmeh-Ghasaban mafic metatexites (Alvand Plutonic Complex, Hamedan, NW Iran), represent a rare natural case study of a low-temperature incipient amphibole-dominated anatectic event of a mafic source with a primary assemblage (Pl+Hbl+Cpx+Bt+Opx) typical of a hornblende-bearing gabbroic rock.

Quantifying Bedrock Recharge In Two Paired Mountainous Watersheds, Kimberly Bolhuis

Graduate Student Theses, Dissertations, & Professional Papers

This study focuses on 1) estimating the magnitude of bedrock recharge and 2) mean transit time as a function of bedrock permeability in two paired catchments underlain by different lithology. Networks of bedrock wells and stream gauges were installed in two adjacent catchments of approximately the same size in west central Montana. Fracture network properties for both lithologies were characterized from borehole core logging and scan lines on exposed outcrop. Recharge was evaluated using the Water Table Fluctuation (WTF) method on bedrock well hydrographs installed in both catchments. Stable water isotope samples, collected approximately monthly, from precipitation and stream water …

Structural And Thermochronologic Evidence Of Paleogene-Neogene Faulting And Exhumation Of The Klamath Mountain Province, Taylor C. Team

Cal Poly Humboldt theses and projects

The Klamath Mountains Province (KMP), located at the southern end of the forearc of the Cascadia Subduction Zone, displays a distinct topographic and geologic signature. Compared to the forearc in the north, the KMP comprises Paleozoic-Mesozoic basement rocks with relatively high modern elevation and relief. This study investigates the pattern of rock cooling in the KMP by using thermochronology on plutons exhumed by faults and plutons outside of mapped faults. In this study, I target three regions in the KMP: the Ashland pluton offset by the Siskiyou Summit fault in the northeast KMP, the Grayback pluton in the northwest KMP, …

New Research On A Case Of Linear Discontinuous Ground Deformation (Ldgd), Andrzej Kowalski, Bartosz Apanowicz, Piotr Polanin

Journal of Sustainable Mining

LSDS is defined as surface fissures, steps as well as structures formed by them in the form of stairs (several steps), thresholds, ditches, and flexure. The paper presents a case study of formed LSDS – the origin, and possible methods to assess its occurrence on the basis of the research carried out in the Central Mining Institute. The authors showed that the presence of LSDS leads not only to the horizontal deformation but also contributes to the formation of vertical curvatures of terrain that cause fissures in the near-surface layer of the rock mass in the areas with a thick …

Tectonic Evolution Of The Tucki Mountain Metamorphic Core Complex, Southeastern California: Evidence For Late Cretaceous Extension Within The Sevier-Laramide Orogen, William Killey Barba

UNLV Theses, Dissertations, Professional Papers, and Capstones

The exhumation of Cordilleran metamorphic core complexes from mid-crustal depths in the western U.S. Basin and Range Province has been classically associated with Cenozoic extension. However, recent studies reveal that extensional tectonic exhumation of numerous metamorphic core complexes initiated during the Late Cretaceous. New geologic mapping and structural analysis integrated with geochronology and thermochronology data provide evidence for a Late Cretaceous extensional shear zone, previously interpreted as Miocene in age, within the Tucki Mountain metamorphic core complex on the western flank of Death Valley, California. The shear zone occurs within the immediate footwall of the Miocene-Pliocene Tucki Mountain detachment fault …

Investigating The Timing Of Initial Louann Salt Flow And Its Relationship With The Gilbertown Fault Zone, Southwest Alabama, Avery Rosenbalm

Master's Theses

The Mesozoic Louann Salt extends through the northern GOM, extending onshore from eastern Texas to western Alabama and Florida. Along the landward terminus of the salt is a system of peripheral faults, including the Gilbertown Fault Zone bordering the Mississippi Interior Salt Basin to the north and east. This study sought to constrain the timing of fault movement and determine its relationship to the baswinward evacuation of Louann Salt through the use of a 3D seismic survey and well logs. By mapping Mesozoic formations and the peripheral fault system, lateral changes in formation thickness were used to generate fault expansion …

Delineating Of The Utica Shale/Point Pleasant Formation Play System To Determine Influence Of The Precambrian Basement In Northeastern Ohio, Jarrod R. Bridges

Electronic Theses and Dissertations

The Utica Shale/Point Pleasant Formation system has recently become a highly developed unconventional target for oil and natural gas production, leading to an increased desire for knowledge of the controls on deposition of this system. Precambrian basement features have long been known to affect deposition of older strata near these features across Ohio, but the effects of far field tectonics is not fully agreed upon. Precambrian faults and lineaments are known to exist and have been mapped, but are thought to have ceased their influence on deposition by the time of the Knox unconformity during the Cambrian. In the case …

Neogene And Quaternary Events Shaped Diversification And Speciation In Bhutanese Rheophilic Fishes Of The Family Nemacheilidae (Cypriniformes) And Sisoridae (Siluriformes), Karma Wangchuk

Graduate Theses and Dissertations

Biogeography of the Himalayan region [to include the Qinghai-Tibetan Plateau (QTP)] evolved over a ~30M year span, catalyzed by the collision of the Indian and Eurasian plates. The resulting uplift produced major ecological and climatic effects, that in turn drove the diversification of biodiversity. As a result, the QTP is designated as a global biodiversity hotspot particularly vulnerable to cumulative climatic effects, including shrinking distributions, declining numbers, and local extinctions. Understanding how the biodiversity within the Himalaya/ QTP was established and maintained is a necessary first step in prioritizing conservation efforts.

Fishes in global montane regions, such as the Himalaya, …

Sediment Provenance Of Tsunami Deposits: Implications For Assessing The Relative Intensity Of Paleotsunamis From The Sendai Coastline Of Japan, Tiffany Otai

Master's Theses

The 2011 Tohoku tsunami impacted the northeastern coast of Japan and caused unexpected damages due to the underestimation of this type of hazard. Of particular importance is the fact that geologic evidence for a predecessor event, the Jogan tsunami (CE 869), could have forecasted the severity of the 2011 Tohoku event. While the timing of tsunamis is important for effective hazard mitigation, outside of the 2011 Tohoku event, the intensity of past tsunamis remains unclear. To understand paleotsunami intensity, it is important to document characteristics of modern analogues like the 2011 event. This study utilizes surface distributions of foraminifera from …

The Fold Illusion: The Origins And Implications Of Ogives On Silicic Lavas, Graham Dm Andrews, Stuart Kenderes, Alan Whittington, Shelby L. Isom, Sarah Brown, Holly Danielle Pettus, Brenna Cole, Kailee Gokey

Faculty & Staff Scholarship

Folds on the surfaces of mafic lavas are among the most readily recognized geological structures and are used as first-order criteria for identifying ancient lavas on Earth and other planetary bodies. However, the presence of surface-folds on the surface of silicic lavas is contested in this study and we challenge the widely accepted interpretation that silicic lava surfaces contain folds using examples from the western United States and Sardinia, Italy. We interpret the ridges and troughs on their upper surfaces, typically referred to as ‘ogives’ or ‘pressure ridges’, as fracture-bound structures rather than folds. We report on the absence of …

Detrital Zircon (U-Th)/He Thermochronology In The Greater Caucasus: Implications For Thermal And Tectonic History Along-Strike, Kate Gutterman

LSU Master's Theses

Located along the northernmost boundary of the Arabia-Eurasia collision zone, the Greater Caucasus are a young, actively deforming mountain range striking WNW-ESE between the Black and Caspian Seas. Previous thermochronometric studies predominantly focused on the western portion of the range partially constrain the thermal and tectonic history of the Greater Caucasus. However, due to the complex nature of the tectonics in the region, multiple competing tectonic models have been suggested to explain the exact timing of collision and onset of rapid uplift. Furthermore, the Greater Caucasus exhibit competing along-strike gradients in modern shortening rates, mean annual precipitation, structural architecture and …

Geologic Map Of The Structural Margin Of Northeastern North America, Daniel Melnick

Earth & Space Sciences Student Work

No abstract provided.