Tectonics and Structure Commons^™

A Record Of The Precambrian-Cambrian Transition In Sw Montana: A Late Neoproterozoic To Early Cambrian Stratigraphic Window, Fortunian Biostratigraphic Assemblage And Treptichnus Pedum, R. Reid Trippe

Graduate Student Theses, Dissertations, & Professional Papers

This study documents a Late Neoproterozoic through Early Cambrian stratigraphic record in the Humbolt anticline of southwestern Montana. The Precambrian-Cambrian transition includes a Fortunian-aged biostratigraphic trace-fossil assemblage with the ichnofossil Treptichnus pedum. The Humbolt anticline represents an inverted paleo-graben that exposes a stratigraphic window interpreted to be a record of rifting along the Cordilleran miogeoclinal margin, linked with the breakup of the Rodinia supercontinent. The graben subsided and captured sediment during late-stage rifting and final-stage dissociation along the rift margin. Its structural axis paralleled the rift margin. Sevier/Laramide orogenic thrusting inverted the graben into the Humbolt anticline. The Late …

Refining The Onset Timing And Slip History Along The Northern Part Of The Teton Fault, Rachel Montague Hoar

Theses and Dissertations--Earth and Environmental Sciences

A new apatite (U-Th)/He (AHe) dataset from subvertical transects collected in the Teton and Gallatin Ranges in the Teton-Yellowstone region provides insight for the slip history and length of the Teton fault. Along the northernmost segment of the Teton fault, inverse thermal history modeling of AHe data from Eagles Rest Peak yield a ~9 Ma age for onset of fault slip. This age supports previous interpretations that Mount Moran may be the true center of the Teton fault. This refined interpretation coupled with lengthdisplacement fault scaling analysis and previous estimates of total fault displacement (~6 km) indicates that the Teton …

Fault Evolution In The Northwest Little San Bernardino Mountains, Southern California: A Reflection Of Tectonic Linkage Between The San Andreas Fault And The Eastern California Shear Zone, Ann Hislop

Theses and Dissertations--Earth and Environmental Sciences

The Little San Bernardino Mountains (LSBM) Fault Set are N-S dextral faults, east of the restraining bend of the San Andreas Fault (SAF) in southern California, that may form a tectonic linkage between the SAF and the Eastern California Shear Zone. The NW LSBM are a complexly deformed structural domain characterized by the young N-S dextral faults and older NW-oriented Dillon Shear Zone faults. Before the 1992 Joshua Tree (M_w 6.1) and Landers (M_w 7.3) earthquakes, the rugged NW LSBM was the subject of few geologic studies. This bedrock mapping study has further delineated the geometry, distribution, and …

Determining Rates Of Landscape Response To Tectonic Forcing Across A Range Of Temporal Scales And Erosional Mechanisms: Teton Range, Wy, Meredith Swallom

Theses and Dissertations--Earth and Environmental Sciences

Understanding how mountain landscapes respond to variations in tectonic forcing over a range of temporal scales in active mountain belts remains as a prominent challenge in tectonic and geomorphological studies. Although a number of empirical and numerical studies have examined this problem, many of them were complicated by issues of scale and climatic variability. More specifically, the relative efficiencies of fluvial and glacial erosion, which are presumably controlled by climate, are difficult to unravel. The Teton Range in Wyoming, which results from motion on the crustal-scale Teton fault, is an ideal natural laboratory for addressing this challenge as the tectonic …

Characterizations Of Linear Ground Motion Site Response In The New Madrid And Wabash Valley Seismic Zones And Seismicity In The Northern Eastern Tennessee Seismic Zone And Rome Trough, Eastern Kentucky, Nicholas Von Seth Carpenter

Theses and Dissertations--Earth and Environmental Sciences

The central and eastern United States is subject to seismic hazards from both natural and induced earthquakes, as evidenced by the 1811-1812 New Madrid earthquake sequence, consisting of at least three magnitude 7 and greater earthquakes, and by four magnitude 5 and greater induced earthquakes in Oklahoma since 2011. To mitigate seismic hazards, both earthquake sources and their effects need to be characterized.

Ground motion site response can cause additional damage to susceptible infrastructure and buildings. Recent studies indicate that Vs30, one of the primary site-response predictors used in current engineering practice, is not reliable. To investigate site response in …

Late Devonian Sedimentary Record Of Appalachian Tectonics And Erosion: Geochronology And Geochemistry Of Detrital Muscovite And Zircon From Central Pennsylvania Strata, Cole T. Gardner

Honors Theses

Foreland basin sediment deposition in North-Central Pennsylvania during Late Devonian time records erosion of hinterland source terranes exhumed during regional plate convergence, including the collisional Acadian orogeny. The Catskill clastic wedge preserves a coarsening-upwards stratigraphic succession from marine to fluvial environments associated with sediment progradation and sea-level regression, yet depositional timescales and quantitative provenance data are largely unconstrained.

Detailed facies analysis of eight outcrops spanning >2 km of stratigraphy in Lycoming Co., Pennsylvania documents distinct upsection changes, interpreted to reflect changes in depositional environments consistent with previous sedimentology of the Catskill clastic wedge. Stratigraphy displays a transition from nearshore marine …

Identifying Key Factors Affecting Translational Landslides In Part Of The Yakima Fold And Thrust Belt, Washington State, Joseph Schilter

All Master's Theses

Washington has one of the fastest growth rates in the nation, and unfortunately also is among the most landslide-prone states. With increased population density and urban sprawl, the need for landslide hazard assessment grows. On the Columbia Plateau in central Washington, the smooth rigid, inclined surfaces of the Columbia River Basalts (CRBs) with loose sediment layers between them induces landslides of large blocks of bedrock. These hazards remain poorly understood, but their significance was heightened by the 2017 Rattlesnake Hills Landslide that currently threatens a community and an interstate highway south of Yakima, Washington. I propose that the strongest influences …

Characterizing The Deformation History Of The Southern Mina Deflection: Field And Structural Studies In The Huntoon Mountains, California-Nevada, Joseph Bodie Mccosby

All Master's Theses

New geologic mapping and structural studies in the Huntoon Mountain area (HMA), California-Nevada document the volcanic and deformation histories across the south-central Mina Deflection (MD). Our work allows us to (a) test whether present-day GPS predicted sinistral slip rates are the same as geologic slip rates in the southern MD, and (b) determine the kinematics of fault slip is transfer through the MD. The HMA exposes primarily Miocene andesitic-dacitic volcanic rocks overlain by the 12.114 ± 0.006 Ma (⁴⁰Ar/³⁹Ar sanidine, Petronis et al., 2019) Tuff of Jack Spring and the 11.399 ± 0.041 Ma (^{40 …}

Pressure, Temperature, And Stress Conditions Of Southern Alpine Fault (New Zealand) Mylonites, Jake T. Reitman

Dissertations and Theses

The Alpine Fault, New Zealand, provides a unique window into the rheologic history of a seismically-active continental plate boundary. Due to lower exhumation rates along southern portions of the fault relative to the well-studied central Alpine Fault, deformation ages vary along strike by ~15 m.y.. Mylonites collected from two southern creeks near Haast, NZ, display a uniform recrystallized grain size of ~11 𝜇m in mylonitic quartz indicating differential stress values in the south of ~100 MPa, roughly twice the stress values observed in the central Alpine Fault. Constraints from Ti-in-quartz thermobarometry and Raman Spectroscopy of Carbonaceous Material (RSCM) indicate mylonitization …

Structural Style And Stratigraphic Architecture Of The Northeastern Brooks Range, Alaska, Benjamin G. Johnson

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Arctic Alaska–Chukotka microplate is a large Mesozoic–Cenozoic composite terrane that resides at the northern limit of the North American Cordillera. Although its Mesozoic origins are assuredly linked to the opening of the Amerasian Basin of the Arctic Ocean, its Paleozoic origins can be linked to at least three separate paleocontinents, including northern Laurentia, Baltica, and Siberia. Across the Arctic Alaska portion of the microplate, an internal, mid-Paleozoic suture zone presumably separates rocks of the North Slope subterrane (Laurentian affinity) from a collection of smaller subterranes in the southern Brooks Range and Seward Peninsula (Baltic affinity).

The mountains of the …

Determining The Precambrian Structure And Thermotectonic Evolution Of The Central Ruby Range, Southwest Montana, Sara Vivienne Stotter

Graduate Student Theses, Dissertations, & Professional Papers

The Ruby Range in southwestern Montana is a fundamental location within the Archean Wyoming craton for examining Precambrian crustal architecture and determining the thermotectonic evolution of the region. Monazite, zircon, and garnet geochronology from each of the three major units within the Ruby Range reveal two distinct metamorphic age populations: an older population ca. 2.55-2.45 Ga (the Tendoy orogeny) and a second, younger population ca. 1.78-1.72 Ga (the Big Sky orogeny). Phase equilibria modeling for the Big Sky orogeny within the confines of the Mine Gulch 7.5’ quadrangle reveal discrete pressure-temperature (P-T)histories for each of the three major …

Effects Of Initial Thermal Structure On The Evolution Of Continental Rifting, Alexandra Wernle

All Master's Theses

Continental rifting is a fundamental earth process that displays a wide variety of styles ranging from narrow to wide, symmetric and asymmetric, magmatic and amagmatic. The key conditions and processes that control the evolution of rifts remain enigmatic. Previous research suggests that the initial thermal structure may have a first order control on the evolving styles of these systems. This project examines the impact of the initial thermal structure on the spatial and temporal evolution of continental rifts using finite element thermo-mechanical modeling. The initial thermal structure is a product of crustal heat production rates and heat conducted from the …

An Analysis Of Fractures Around The Sevier Fault Zone Near Orderville, Utah, Charley H. Hankla

Senior Independent Study Theses

Structural discontinuities—such as opening mode joints, shear fractures, and faults— tend to occur in close geographic proximity to one another; however, the timing relationships between these structures is not always easy to discern in the field. In southwestern Utah, the Jurassic Navajo Sandstone is cut by large-scale normal faults associated with the Sevier Fault Zone, making it perfect for observing several fracture types. The aim of this study is to complete a dynamic and kinematic analyses of the fractures near a major fault and to determine the chronologic relationships between the fractures. Specifically, we observed a previously unnamed segment of …

Groundwater Level Response To The Wenchuan Earthquake Of May 2008, Anhua He, Ramesh Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

We have comprehensively analysed the co-seismic response of the groundwater levels of 280 wells in mainland China that were associated with the Wenchuan earthquake (Mw 7.9) that occurred on 12 May 2008. The observed co-seismic responses can be classified as step-like changes in 138 wells, variations in 69 wells and non-responses in 73 wells. After a quantitative analysis of spatial distribution, there was no spatially coherent signal found in the step-like changes (positive values indicate a step-like rise, and negative values indicate a step-like fall), even within 300 km of the epicenter. The amplitude and the phase shift of the …

Land Use And Land Cover Changes, And Environment And Risk Evaluation Of Dujiangyan City (Sw China) Using Remote Sensing And Gis Techniques, Biswajit Nath, Zheng Niu, Ramesh P. Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

Understanding of the Land Use and Land Cover (LULC) change, its transitions and Landscape risk (LR) evaluation in earthquake-affected areas is important for planning and urban sustainability. In the present study, we have considered Dujiangyan City and its Environs (DCEN), a seismic-prone area close to the 2008 Wenchuan earthquake (8.0 Mw) during 2007–2018. Five different multi-temporal data sets for the years 2007, 2008, 2010, 2015, and 2018 were considered for LULC mapping, followed by the maximum likelihood supervised classification technique. The individual LULC maps were further used in four time periods, i.e., 2007–2018, 2008–2018, 2010–2018, and 2015–2018, to evaluate the …

Crustal Seismic Anisotropy Of The Ruby Mountains Core Complex And Surrounding Northern Basin And Range, Justin T. Wilgus

Earth and Planetary Sciences ETDs

Metamorphic core complexes (MCC) are distinctive uplifts that expose deeply exhumed and deformed crustal rocks due to localized extensional deformation. Consequently, their detailed structure provide a window into deep crustal mechanics. The North American Cordillera contains numerous MCC, one of which is the Ruby Mountains core complex (RMCC) located in the highly extended northern Basin and Range. To constrain the extent to which anisotropy below the RMCC deviates from the regional Basin and Range average and test the depth dependence of crustal anisotropy we conduct a radial anisotropy investigation below the RMCC and surrounding northern Basin and Range. Data from …

The Cyrilka Cave—The Longest Crevice-Type Cave In Czechia: Structural Controls, Genesis, And Age, Jan Lenart, Martin Kašing, Petr Tábořík, Natalia Piotrowska, Jacek Pawlyta

International Journal of Speleology

The Cyrilka Cave is the second longest pseudokarst cave and the longest crevice-type cave in Czechia. Developed within the headscarp area of a deep-seated landslide, the cave became a focus of scientific research in recent years when new passages were discovered. Structural analysis provided a general tectonic plan of the cave, as well as more detailed data on geometry and kinematics of the relaxed rock massif. The primary structure of NNE- to ENE-striking bedding is broken by a system of NNE-striking fissures interconnected by two continuous ENE-striking dextral fracture zones. Abundant signs of recent sinistral strike-slips within the rock massif …

New Borehole Breakout Derived Stress Constraints And Their Implications For Stress Heterogeneity Near High Risk Fault Systems In The Santa Barbara Channel, Southern California, Edward Harris Pritchard

LSU Master's Theses

The Santa Barbara Channel represents the offshore portion of the Ventura Basin in Southern California. Ongoing transpression related to a regional left step in the San Andreas Fault has led to the formation of E-W trending en-echelon fault systems, with both north and south dips, which accommodate varying rates of localized shortening across the basin. Recent studies have suggested that faults within the northern region of the channel could be capable of a multisegment rupture and producing a M_w 7.7–8.1 tsunamigenic earthquake. However, dynamic rupture models producing these results have not accounted for stress heterogeneity, which is …

Unroofing History Of The Northwestern Ethiopian Plateau: Insights From Low-Temperature Apatite Thermochronology, Shelby Bowden

Masters Theses & Specialist Projects

The geology of Ethiopia is dominated by the Ethiopian Plateau that is similar in elevation to, but aerially larger than, the Colorado Plateau. Several rivers have incised through the plateau, creating gorges that reach up to 1.5 km in depth. The plateau uplifted to its current elevation and was subsequently incised sometime after the Oligocene flood basalt event that signaled the arrival of the African Superplume below Kenya and Ethiopia. Due to its size and extent, published climate modeling has indicated that Late Cenozoic plateau formation could have been a driving force in the East African Cenozoic climate changes. Although …

Structural Evolution And Petroleum Potential Of A Cambrian Intracratonic Rift System: Mississippi Valley Graben, Rough Creek Graben, And Rome Trough, John B. Hickman, David C. Harris

Report of Investigations--KGS

Drilling and geophysical data demonstrate that the Mississippi Valley Graben, Rough Creek Graben, and Rome Trough are fault-bounded structures filled with as much as 27,000 ft of Cambrian sediments. Data including stratigraphic tops from 1,764 wells, 106 seismic profiles, aeromagnetic and gravity surveys, and mapped surface geology at a scale of 1:24,000 were used to study seven stratigraphic packages across parts of Kentucky, Ohio, Indiana, Illinois, Missouri, and Tennessee. Detailed analysis of the thickness patterns of these stratigraphic packages was used to interpret the locations and timing of movement along major fault systems in the study area.

Active rifting of …

On The Interaction Of The North Andes Plate With The Caribbean And South American Plates In Northwestern South America From Gps Geodesy And Seismic Data, Omar J. Pérez, Steven G. Wesnousky, Roberto De La Rosa, Julio Márquez, Redescal Uzcátegui, Christian Quintero, Luis Liberal, Héctor Mora-Páez, Walter Szeliga

All Faculty Scholarship for the College of the Sciences

We examine the hypocentral distribution of seismicity and a series of geodetic velocity vectors obtained from Global Positioning System observations between 1994 and 2015 both offshore and mainland northwestern South America (66°W–77°W; 8°N–14°N). Our analysis, that includes a kinematic block modelling, shows that east of the Caribbean–South American–North Andes plates’ triple junction at ∼68°W; 10.7°N, right-lateral easterly oriented shear motion (∼19.6 ± 2.0 mm yr⁻¹) between the Caribbean and South America plates is split along two easterly striking, right-lateral strike-slip subparallel fault zones: the San Sebastián fault that runs off-shore the Venezuelan coast and slips about 17.0±0.5mm …

Stylolites Cathodoluminescence Under Cross Polarized Light, Katherine Dvorak

The Hilltop Review

Devil's Gate limestone under cathodoluminescence. Bright yellow and orange areas are calcite and the bright blue indicates trace minerals along the solution seam. Trace minerals left in the seam are heavy metals and other silicate minerals.

The Transition From Sevier To Laramide Orogeny Captured In Upper-Plate Magmatic Structures, Eastern Transverse Ranges, Ca, Brody Friesenhahn

Earth Sciences Theses and Dissertations

The onset of the Laramide orogeny is of great tectonic significance to the geologic history of the US, but the timing and nature of the shift between Sevier and Laramide tectonics remains enigmatic. The eastern Transverse Ranges of southern California provide the opportunity to observe the effects of Laramide tectonics on the mid-crust. Wide Canyon is a north/south-trending canyon in the northern Little San Bernardino Mountains of the eastern Transverse Ranges. Al-in-hornblende thermobarometry of Needy et al. (2009) yields a projected paleodepth depth of ~20 km for Wide Canyon where Cretaceous granitoids intrude metamorphic country rock of Proterozoic age in …

Review Of Curbing Catastrophe: Natural Hazards And Risk Reduction In The Modern World, Kira H. Hamman

Numeracy

Timothy H. Dixon. 2017. Curbing Catastrophe: Natural Hazards and Risk Reduction in the Modern World. (New York, NY: Cambridge University Press) 300 pp. ISBN 978-1108113663.

In Curbing Catastrophe, Timothy H. Dixon explores commonalities among natural disasters like Hurricane Katrina, the 2010 earthquake in Haiti, and the meltdown at Fukushima. He identifies communication failure between scientists and policy makers as a major culprit in the devastation that results from such events and offers strategies for improving that communication. He includes optional in-depth scientific and quantitative examinations of the events and the resulting devastation, making the book appropriate for use …

Integrated Geophysical Analysis In The Northeastern Gulf Of Mexico, Mei Liu

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

The formation of the Gulf of Mexico (GoM) relates to the breakup of Pangea and opening of the central Atlantic Ocean. The tectonic history of the basin is still being debated due to lack of geological constraints. This project addresses the crustal architecture in the northeastern GoM from integrative analysis of multiple geophysical datasets to provide constraints for the tectonic reconstruction.

The objectives of this study are: 1) to delineate various tectonic zones (continental and oceanic domains) and map the boundary between them, 2) to derive physical properties of the subsurface rocks, 3) to map the major tectonic structures in …

Large Rotations Of Crustal Blocks In The Tjörnes Fracture Zone Of Northern Iceland, Andrew J. Horst, J. A. Carson, R. J. Varga

Natural Resources and Earth Sciences Faculty Research

The interpretation of uppermost crustal deformation near oceanic transform faults is based on bathymetric lineaments and earthquake focal mechanisms, and relatively little is known about the detailed kinematics within the transform tectonized zone. The Tjörnes Fracture Zone is a broad zone of deformation produced by right‐lateral transform shearing in north Iceland and is partly exposed on land providing the opportunity to study shallow‐level crustal structure of mid‐Miocene, thick, oceanic‐like crust formed by subaerial spreading. A pronounced structural curvature of lava and dike orientations near the Húsavík‐Flatey Fault within the transform zone is well documented, yet of controversial origin. In order …

Miocene-Quaternary Deformation Along The Central Maynard Lake Fault, Pahranagat Shear Zone, Nevada, Alexander Peck

UNLV Theses, Dissertations, Professional Papers, and Capstones

The left-lateral Pahranagat shear zone (PSZ) and Caliente-Enterprise zone (CEZ) exist at the boundary between two sub-provinces, the Northern (NBR) and Central Basin and Range (CBR). The PSZ contains three major ENE striking sinistral faults, including the Maynard Lake fault (MLF), which is the longest fault and marks the southern boundary of the zone. The PSZ has been suggested to be a transfer zone, but little is known about the structures along these major faults that are involved in strain transfer. These left-lateral systems exist within the Central Nevada seismic belt which has experienced significant earthquakes in recent history. Possible …

Structural Geology Of The Caddo Gap Area, Ouachita Mountains, Arkansas, Martin Messmer

Electronic Theses and Dissertations

The Caddo Gap quadrangle is located on the southern margin of the Benton Uplift, the orogenic core of the Ouachita Mountains. Recent field mapping focused on delineating stratigraphic and structural relationships in the southern part of the quadrangle to improve existing reconnaissance-scale maps of the area. New structures were discovered that provide further information about the structural evolution of the Ouachita fold and thrust belt.

Field work included mapping the three informal members (Lower, Middle and Upper) of the Arkansas Novaculite. Major folds within the study area include the Nelson Mountain Anticline and two synclinal folds (“South Caddo Mountain” and …

Evolution And Controls Of Large Glacial Lakes In The Nepal Himalaya, Umesh K. Haritashya, Jeffrey S. Kargel, Dan H. Shugar, Gregory J. Leonard, Katherine Strattman, C. Scott Watson, David Shean, Stephan Harrison, Kyle T. Mandli, Dhananjay Regmi

Department of Earth, Environment and Sustainability Faculty Publications

Glacier recession driven by climate change produces glacial lakes, some of which are hazardous. Our study assesses the evolution of three of the most hazardous moraine-dammed proglacial lakes in the Nepal Himalaya—Imja, Lower Barun, and Thulagi. Imja Lake (up to 150 m deep; 78.4 x 10⁶ m³ volume; surveyed in October 2014) and Lower Barun Lake (205 m maximum observed depth; 112.3 x 10⁶ m³ volume; surveyed in October 2015) are much deeper than previously measured, and their readily drainable volumes are slowly growing. Their surface areas have been increasing at an accelerating pace from a …

Supplemental Data For 'Evolution And Controls Of Large Glacial Lakes In The Nepal Himalaya', Umesh K. Haritashya, Jeffrey S. Kargel, Dan H. Shugar, Gregory J. Leonard, Katherine Strattman, C. Scott Watson, David Shean, Stephan Harrison, Kyle T. Mandli, Dhananjay Regmi

Department of Earth, Environment and Sustainability Faculty Publications

Supplementary data for the article "Evolution and Controls of Large Glacial Lakes in the Nepal Himalaya"