Tectonics and Structure Commons^™

Modeling The Greenland-Iceland-Faroe Ridge Using Integrated Geophysical Analysis, Zachary Clowdus

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

The Greenland-Iceland-Faroe Ridge (GIFR) is an area of significant geologic interest with anomalously thick crust related to enhanced melt generation from the interaction between the Mid-Atlantic Ridge and the Iceland hotspot. To the northeast of Iceland lies the Jan Mayen Microcontinent (JMMC), which is a continental fragment separated from Greenland during the opening of the Northern Atlantic. The overall extent of the JMMC, especially its southern boundary, remains poorly constrained. The crust beneath the GIFR is believed to be primarily of oceanic affinity. However, a recent discovery of felsic lavas in Iceland led to an alternative hypothesis that implies the …

Seismological Applications To Crustal Deformation And Explosion Discrimination, Olumide Adedeji

Earth and Planetary Sciences ETDs

There are many outstanding questions in seismology and plate tectonics that remain unresolved due to the complexity of seismic wave propagation, fault system evolution, and sedimentary-tectonic interactions. In this dissertation, I analyze seismic and acoustic data to improve event discrimination, understand strain partitioning along a transpressive plate boundary, and investigate the influence of tectonic deformation on sedimentary processes. Using seismic arrays, I assess the detectability of Ground Coupled Airwaves (GCA) generated by shallow borehole explosions and earthquakes, demonstrating that GCA detections are highly dependent on source type, environmental conditions and sensor distribution. Along the Queen Charlotte Plate Boundary, I analyze …

Differential River Incision Due To Quaternary Faulting On The Río Jemez-Salado System At The Million-Year Timescale, Cameron Reed

Earth and Planetary Sciences ETDs

Analysis of long-term average bedrock incision rates along the Río Salado-Jemez system using fluvial terraces can be used to test and quantify the hypothesis that differential river incision reflects Quaternary fault slip during ongoing uplift of the Jemez and Nacimiento Mountains. Terrace flights were correlated from the Arroyo Peñasco to the Río Salado near the southern nose of the Nacimiento and along the Río Jemez. Using highest/oldest river terraces, resulting bedrock incision values average out glacial/interglacial cycles and are interpreted to reflect differential uplift. For previously mapped and correlated terraces, we applied lidar datasets to refine strath heights. We also …

Assessing Seismic Hazard In Western Kentucky And At The Paducah Gaseous Diffusion Plant: An Overview Of The Issues, Mitigation Strategies, And The Research Conducted By The Kentucky Geological Survey, Zhenming Wang, Seth Carpenter

Bulletin--KGS

The exposure of homes, infrastructure, and critical facilities in western Kentucky, including the Paducah Gaseous Diffusion Plant (PGDP), to potential strong seismic shaking from the New Madrid Seismic Zone (NMSZ) has been a major impetus for decades of effort to characterize seismic hazards by the Kentucky Geological Survey (KGS). The purpose of this report is to provide 1) a summary of the earthquake hazards that affect Kentucky and KGS’s ongoing earthquake research, including seismic monitoring, 2) background on the types of seismic hazards in general and how they are quantified in seismic hazard assessments, including strengths and weaknesses of the …

Limits Of Tectonic Reactivation On Mars Using Earth Analogue Analysis And Numerical Modeling, Jonathan Rich

Theses and Dissertations

Recent geodynamic modeling studies suggest that the geometry of structural landforms in the Ouachita Mountains (OM) has been influenced by the reactivation of a weak scar in the mantle-lithosphere during intracontinental orogenesis. As deformation on one-plate planets such as Mars can be considered intracontinental, and impact cratering deeply scarred the Martian lithosphere, we hypothesize that structural geometries on Mars may also reflect heterogenous networks of lithospheric scarring. To investigate this hypothesis, we model the pre-erosional fold structure of the Maumelle Chaotic Zone in the OM to compare fault and fold geometries with that of the seismically-imaged mantle-lithosphere scar. We then …

Tectonic Evolution Of The Northern Margin Of North America, Karol Faehnrich

Dartmouth College Ph.D Dissertations

The northern margin of North America records a protracted history of Neoproterozoic–early Paleozoic rifting and passive margin development, followed by the middle Paleozoic accretion of continental fragments. Contrasting tectonic models have been proposed for the history of continent separation, the role of strike-slip displacement during terrane accretion, and the Mesozoic opening of the Arctic Ocean. Here, I explore several of these models by investigating Neoproterozoic–early Paleozoic sedimentary and volcanic rocks across the northern margin of North American, as well as the main faulted boundaries between displaced terranes and autochthonous rocks of North America. First, I present a new tectonic model …

Syn- To Post-Orogenic Evolution Of Collisional Mountain Systems: Investigating The Potential For Crustal Flow Using Thermochronology And Numerical Models, Brandon Spencer

Theses and Dissertations--Earth and Environmental Sciences

This dissertation is composed of three distinct manuscripts which collectively investigate processes that contribute to the late evolution of collisional mountain systems —specifically, the ancient Appalachian-Caledonian system. In the first paper, ⁴⁰Ar/³⁹Ar thermochronological data are used to constrain the timing of exhumation of the Scandian orogenic wedge of northern Scotland. Muscovite and amphibole samples yield dates of ca. 420-411 Ma, consistent with cooling after peak orogenesis. During this cooling phase, dates from both systems in individual thrust sheets show an increase in cooling rate in the later stage of exhumation; in the orogenic core, the cooling rate …

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, …

Integrated Studies Of Intracontinental Deformation In The Interior Western Usa, Cretaceous To Recent, Jacob Oliver Thacker

Earth and Planetary Sciences ETDs

The advent of plate tectonic theory satisfactorily explained a number of deformation belts around the world. However intracontinental deformation (deformation inboard of a plate margin) remains poorly understood in plate tectonic models. In order to further our understanding of intracontinental tectonics and its effects, this dissertation examines paleotectonic and neotectonic settings within the interior western USA.

Chapter 1 focuses on late Miocene–Recent deformation inboard of the San Andreas plate margin fault and its role on the integration history of the lower Colorado River. The neotectonic analysis included geometric and kinematic fault data collected in key geologic units to characterize the …

Testing Interpretations Of The Displacement Magnitude Of The Teton Fault And Uplift Of The Teton Range, Wyoming With Integrated Flexural-Kinematic And Thermal Modeling, Autumn Helfrich

Theses and Dissertations--Earth and Environmental Sciences

The Teton fault is a range-front normal fault in northwestern Wyoming. Previous estimates of the maximum displacement (D_max) on the Teton fault cover a wide range (2 - 11 km). Discrepancies also exist regarding the slip onset timing, which spans 2 - 13 Ma. To address these discrepancies, the exhumation history of the Teton Range is here investigated using forward flexural-kinematic (Move) and thermal-kinematic (Pecube) models that can be compared with previously reported apatite fission track (AFT) and apatite (U-Th)/He (AHe) ages from Mount Moran, which has been previously hypothesized to represent the …

Applying Garnet And Zircon Ree Linkages To Determine Timing Of P-T Conditions And Tectonic Implications For Uhp Eclogites And Hp Granulites, Dulan Uhp Terrane, China, Wesley Weisberg

All Master's Theses

The Dulan ultrahigh-pressure (UHP) terrane in western China hosts rocks that record continental collision, however; the timing of peak P-T conditions in UHP eclogites and HP granulites, and the tectonic significance of their spatial relationship within the Dulan UHP terrane are not well understood. This study, (1) evaluates rare earth element (REE) equilibrium between garnet and zircon, to assess coeval growth; (2) links timing (from zircon) to the P-T history (from garnet) to constrain the P-T-t path of the Dulan UHP terrane and interpret implications for zircon growth; (3) refines P-T conditions for HP granulite; and (4) evaluates the tectonic …

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 …

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 …}

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 …

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 Cross Sections And Subsurface Maps Of The Atoka Formation In The Northern Arkoma Basin, Western And Northwestern Arkansas, David Nance

Graduate Theses and Dissertations

The Arkoma Basin is one of several peripheral foreland basins situated on the front of the Ouachita orogenic fold and thrust belt. The transition from the foredeep to the Ozark Plateaus is a short one in terms of latitude. The Atoka Formation in Arkansas comprises the bulk of the sediments in the Arkoma Basin. Three divisions of the Atoka Formation have been informally assigned as the Upper, Middle, and Lower based on differences in sedimentary response to tectonic processes that occurred during the formation and subsidence of the Arkoma Basin. In the Arkansas portion of the Arkoma Basin, the lower …

Spatial And Temporal Characterization Of The Petrified Springs Fault, Central Walker Lane, Nevada: Documenting Middle Miocene Dextral Slip, Andrew Hoxey

All Master's Theses

The Central Walker Lane, NV is an active dextral shear zone superimposed on the western boundary of the Basin and Range extensional province. Approximately 25% of dextral shear along the Pacific-North American plate boundary accommodated in the Walker Lane, a NW-striking, intracontinental dextral fault system in eastern California- western Nevada. In the Central Walker Lane, shear is accommodated on five major NW- striking faults, one of which is the Petrified Springs fault, with poorly constrained slip magnitudes, slip rates, and initiation ages. We completed new detailed geologic mapping, combined with structural studies, and ⁴⁰Ar/³⁹Ar geochronology document offset …

The Dynamic Relationship Between The Bear River, Quaternary Basaltic Center, Normal Faults, And The Resulting Rearrangement Of Rivers In The Northeast Edge Of The Great Basin, Southeast Idaho, Brady Utley

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The objective of this research project in Gem Valley graben, southeast Idaho is to identify the location, age and history of the Quaternary diversion of the Bear River into paleo-Lake Thatcher, and then into the Lake Bonneville basin from the Columbia River basin. Mapping, geochemical analysis, cross-cutting relationships, and five new age determinations, together with prior published research, shed new light on the complex history of interaction between the volcanic rocks, rivers, lakes, and faults in Gem Valley. Research goals were to test the hypothesis that local faulting and volcanism drove the diversion of the Bear River and controlled the …

Investigations On The Mesozoic Geologic And Tectonic History Of The Jackson Mountains, Northwest Nevada, Thomas Anthony Colby

Boise State University Theses and Dissertations

New geologic mapping, high-precision U-Pb zircon geochronology, and isotope geochemistry provide insight into the early Mesozoic paleogeography and magmatic, stratigraphic, and structural evolution of the Jackson Mountains in the Black Rock Desert region of northwest Nevada. The magmatic history of the Jackson Mountains records Late Triassic to Early Jurassic (~215-195 Ma) marine deposition of the Boulder Creek Beds adjacent to the arc followed by the Early Jurassic (~193-189 Ma) eruption and emplacement of the Happy Creek Igneous Complex and associated plutons of the Early Mesozoic Intrusive Suite. Pb, Sr, and Nd isotopic data from Early Jurassic intrusive rocks of the …

Strain Analysis Across The Margins Of The Elkahatchee And Coley Creek Plutons, Alabama Eastern Blue Ridge: Implications For The Alexander City Fault, Kenneth Joel Roop-Eckart

Theses and Dissertations

The Ashland-Wedowee-Emuckfaw belt of the eastern Blue Ridge of Alabama and Georgia consists of metamorphosed Neoproterozoic-Ordovician continental margin and Ordovician back-arc sedimentary/volcanic sequences intruded by Ordovician-Mississippian granitic plutons. Two of these plutons, the Elkahatchee Quartz Diorite and Coley Creek orthogneiss exhibit zones of high strain, evidenced by mylonitic fabrics, ductile deformation of feldspar grains, grain size reduction, and changes in mica content at their margins. Geologic mapping in the vicinity of the Coley Creek pluton shows no evidence for a ductile shear zone beyond its margins and thus, is unlikely to be associated with a major fault. More likely, this …

Crustal And Upper-Mantle Structure Beneath Ice-Covered Regions In Antarctica From S-Wave Receiver Functions And Implications For Heat Flow, C. Ramirez, Andrew A. Nyblade, S. E. Hansen, Douglas A. Wiens, Sridhar Anandakrishnan, Richard C. Aster, Audrey D. Huerta, Partick Shore, Terry Wilson

Geological Sciences Faculty Scholarship

S-wave receiver functions (SRFs) are used to investigate crustal and upper-mantle structure beneath several ice-covered areas of Antarctica. Moho S-to-P (Sp) arrivals are observed at ~6–8 s in SRF stacks for stations in the Gamburtsev Mountains (GAM) and Vostok Highlands (VHIG), ~5–6 s for stations in the Transantarctic Mountains (TAM) and the Wilkes Basin (WILK), and ~3–4 s for stations in the West Antarctic Rift System (WARS) and the Marie Byrd Land Dome (MBLD). A grid search is used to model the Moho Sp conversion time with Rayleigh wave phase velocities from 18 to 30 s period to estimate crustal …

Upper Mantle Structure Of Central And West Antarctica From Array Analysis Of Rayleigh Wave Phase Velocities, David S. Heeszel, Douglas A. Wiens, Sridhar Anandakrishnan, Richard C. Aster, Ian W.D. Dalziel, Audrey D. Huerta, Andrew A. Nyblade, Terry J. Wilson, J. Paul Winberry

Geological Sciences Faculty Scholarship

The seismic velocity structure of Antarctica is important, both as a constraint on the tectonic history of the continent and for understanding solid Earth interactions with the ice sheet. We use Rayleigh wave array analysis methods applied to teleseismic data from recent temporary broadband seismograph deployments to image the upper mantle structure of central and West Antarctica. Phase velocity maps are determined using a two–plane wave tomography method and are inverted for shear velocity using a Monte Carlo approach to estimate three-dimensional velocity structure. Results illuminate the structural dichotomy between the East Antarctic Craton and West Antarctica, with West Antarctica …

Spatial Scaling Of Crustal And Lithospheric Deformation In The Western United States, Cody W. Bomberger

Graduate Student Theses, Dissertations, & Professional Papers

Deformation of continental lithosphere can extend great distances laterally from tectonic plate boundaries. This extent has been used to argue for a variety of constitutive laws for continental materials, based on the underlying principles in continuum mechanics that identify a relationship between characteristic spatial scale and material properties. Although the relationship between observed deformation and material models is always non-unique, quantifying one or more characteristic scales of deformation in a region can rule out some models of how the lithosphere deforms. In the western United States active deformation occurs at the plate boundary between North America and either the Pacific …

Hidden Intrabasin Extension: Evidence For Dike-Fault Interaction From Magnetic, Gravity, And Seismic Reflection Data In Surprise Valley, Northeastern California, Noah D. Athens, Jonathan M.G. Glen, Simon L. Klemperer, Anne E. Egger, Valentina C. Fontiveros

All Faculty Scholarship for the College of the Sciences

The relative contributions of tectonic and magmatic processes to continental rifting are highly variable. Magnetic, gravity, and seismic reflection data from Surprise Valley, California, in the northwest Basin and Range, reveal an intrabasin, fault-controlled, ~10-m-thick dike at a depth of ~150 m, providing an excellent example of the interplay between faulting and dike intrusion. The dike, likely a composite structure representing multiple successive intrusions, is inferred from modeling a positive magnetic anomaly that extends ~35 km and parallels the basin-bounding Surprise Valley normal fault on the west side of the valley. A two-dimensional high-resolution seismic reflection profile acquired across the …

Qualitative Comparison Of Offset Surfaces Between The Central And Eastern Garlock Fault, Thomas M. Crane

Electronic Theses, Projects, and Dissertations

The Garlock Fault consists of three distinct segments, known as western, central, and eastern, together reaching approximately 260 km from the San Andreas Fault to the southern end of Death Valley. Although published slip rates are available along the western and central Garlock Fault segments, little is currently known of the Garlock Fault earthquake history or slip rate farther east. Using LiDAR and satellite imagery, the central and eastern Garlock Fault segments were analyzed for visibly offset, fault-adjacent, geomorphic surfaces that may potentially be used for estimating slip rate. Qualitative methods of assessing preserved alluvial surface maturity were adapted and …

Sedimentology Of The Upper Scotland Formation (Eocene), Barbados, Krishna Mahabir, Nazrul I. Khandaker, Jay P. Persaud, Stanley Schleifer

Publications and Research

Representative samples collected from the Lower Scotland Formation (Eocene) outcropping in northeastern Barbados were investigated in conjunction with overall facies distribution and stratigraphic and sedimentological characteristics to interpret depositional environment and provenance of the fine-grained clastics. The Lower Scotland Formation is, for the most part, a fine-grained clastic-dominated sequence with occasional thin intercalations of gypsum, ironstone, and kaolinite. Distinctive deep-water-facies have been well-documented in dark gray shale units containing load cast, flutes, grooves and prods. In addition, turbiditic brown sandstone with a sharp erosive base and pelagic caps also characterize the base of the formation. Notable marine fauna observed include …

Significance Of The Deformation History Within The Hinge Zone Of The Pennsylvania Salient, Appalachian Mountains, Mary Beth Gray, Peter B. Sak, Zeshan Ismat

Faculty Journal Articles

Two competing models exist for the formation of the Pennsylvania salient, a widely studied area of pronounced curvature in the Appalachian mountain belt. The viability of these models can be tested by compiling and analyzing the patterns of structures within the general hinge zone of the Pennsylvania salient. One end-member model suggests a NW-directed maximum shortening direction and no rotation through time in the culmination. An alternative model requires a two-phase development of the culmination involving NNW-directed maximum shortening overprinted by WNW-directed maximum shortening. Structural analysis at 22 locations throughout the Valley and Ridge and southern Appalachian Plateau Provinces of …

Pennsylvanian To Cretaceous Folds And Thrusts In South-Central Nevada: Evidence From The Timpahute Range, Angela Giovanna Russo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Understanding Permian and Mesozoic contractional structures from southern California to northern Nevada requires correlation through south-central Nevada. After the Devonian-Mississippian Antler orogeny through the Permian-Triassic Sonoma orogeny and then up to the Sevier orogeny, south-central Nevada was thought to have remained tectonically inactive. However, Pennsylvanian through Jurassic age deformation is documented to the south in Death Valley and to the north. Identifying geometries, spatial relationships, and relative timing of deformations in the Timpahute Range, south-central Nevada, is an essential piece to completing the overall understanding of Nevada geology. The purpose of this study is to identify and analyze deformational structures …

Application Of (U-Th)/He And 40ar/39ar Thermochronology To The Age Of Thrust Faulting In The Sevier Orogenic Belt, Michael Giallorenzo

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Sevier fold-thrust belt of the Cordilleran orogen in the western United States is a well-studied geologic province, yet our understanding of the history of thrust faulting is still far from complete. Thermochronological methods are applied to major thrust systems from two distinct sections of the Sevier fold-thrust belt (SFTB): the Wheeler Pass thrust in the Mojave Desert section of the southern SFTB, and the Willard thrust in the Idaho-Utah-Wyoming section of the SFTB. The new thermochronological data greatly improve our understanding of the structural evolution of this extensive geologic province.

The zircon (U-Th)/He (ZHe) system records thrust-induced uplift and …

Tectonosedimentologic Significance Of The Upper Cretaceous Foreland Basin Siliciclastics: Western Interior, Usa, Nazrul I. Khandaker

Publications and Research

The Upper Cretaceous Frontier Formation exposed along the western margin of the western interior foreland basin is composed of clastic sediments that were deposited during the initial late Cretaceous transgressive-regressive phases of the Western Interior Seaway across Wyoming (Figure 1). Current study is aimed at providing attendees with the best practices associated with tectonic, lithofacies and sedimentologic interpretation of foreland basin sequences and emphasizing the need for utilizing field, structural, geochemical, and compositional data for reconstructing a viable scenario connected with foreland basin sedimentary packages. An attempt will be made to compare documented sedimentological findings with foreland basins located in …