Tectonics and Structure Commons^™

Potential Field Modeling Across The Neodymium Line Defining The Paleoproterozoic-Mesoproterozoic Boundary Of The Southeastern Margin Of Laurentia, Rachel Lauren Durham

Theses and Dissertations--Earth and Environmental Sciences

A zone of high magnetization along the SE margin of Paleoproterozoic Laurentia in the United States is indicated by magnetic anomaly data. The SE edge corresponds to the geochemical Neodymium mantle derivation model age (T_DM) boundary and the entire anomaly overlies the Paleoproterozoic Mazatzal Province. Two-dimensional gravity and magnetic models across the Nd boundary are created with Moho constrained from receiver functions with gravity, sedimentary thickness and the base of the crustal magnetization. Upper crustal magnetization does not show strong variation across this boundary and much of the strong magnetization appears to lie in the middle crust. Using …

Surface Offset And Slip Rates For The Winter Rim Fault System In The Summer Lake Basin, Oregon, Jennifer Hall

All Master's Theses

The 66-km-long Winter Rim Fault (WRF) system, located in the northwestern Basin and Range Province, encompasses several Holocene fault scarps within the Summer Lake basin that include the WRF system, a normal fault divided into three segments: Slide Mountain (SMF), Winter Ridge, and Ana River (ARF), and the newly-mapped Thousand Springs fault (TSF). The current least-compressive stress field is oriented ~264° (Crider, 2001). The USGS estimates a slip rate of 0.43 mm/yr, earthquake magnitudes of 6.5-7.19, and recurrence interval of 3.1 ka (Crone et al., 2009). However, these estimates are only based upon ARF and the unfavorably slip-oriented SMF. With …

Pressure Dependence Of Polycrystalline Magnesite And Dolomite, Cole Blasko

Williams Honors College, Honors Research Projects

Intermediate depth (170-400 km) deep focus earthquakes are observed in subducting slabs, but unlike shallow (50-170 km) and deep (400-660 km) deep focus earthquakes, the mechanism(s) responsible for them are not clear. Two common alteration products observed in peridotites, magnesite and dolomite, are stable along the pressure-temperature path of a subducting slab. Low pressure experiments indicate that these minerals are weaker than olivine, but there are no data about the pressure dependence of the strength of magnesite or dolomite. Magnesite and dolomite cylinders (1mm by 1mm) were deformed in stacked series to 25-30% strain using the deformation-DIA (DDIA) at Argonne …

Mechanisms Of Shear Zone Localization And Raman Thermobarometry In Spinel Peridotites From The Alpine Fault, New Zealand, Emily J. Lubicich

Dissertations and Theses

A suite of xenoliths from two localities on South Island, New Zealand, exhibit rare microstructures and provide information on deformation during the early stages of development of the Alpine Fault. The first set of samples has evidence of dislocation creep with subgrains, recrystallized grains, undulose extinction and a lattice preferred orientation. These samples also show evidence of post deformation static grain growth with polygonal grains, 120° triple junctions, and euhedral grains within larger grains of the same phase. Samples from the second locality also show evidence of dislocation creep but with minimal static grain growth. This set also has a …

Archived Rock Samples From Jane Selverstone's Research Collection, Jane Selverstone

Earth and Planetary Sciences Faculty and Staff Publications

This Excel spreadsheet lists all of the rock samples from Jane Selverstone's research collection that have been archived into the Earth and Planetary Sciences Collections at the University of New Mexico. All samples are listed by original (published) sample number and by an affiliated International GeoSample Number. Samples are grouped by research project, and doi information is given for all publications resulting from work on each project. Rock samples include various combinations of hand specimens, powders, thin sections, and billets from which thin sections were prepared. Information is included to identify the drawers within which each sample can be found …

Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub

Electronic Theses and Dissertations

The Delaware Basin of West Texas and southeastern New Mexico is the major western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karsting. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during the summer of 2015 documented abundant karst landforms in close proximity to a major thoroughfare, RM 652, in Culberson County, Texas. 2D …

Record Of Massive Upwellings From The Pacific Large Low Shear Velocity Province, Pilar Madrigal, Esteban Gazel, Kennet E. Flores, Michael Bizimis, Brian Jicha

Publications and Research

Global tomography and numerical models suggest that mantle plume occurrences are closely linked to the margins of large low-shear velocity provinces (LLSVPs)1–4. In these marginal zones the ascent of material from the core-mantle boundary connects deep mantle dynamics with surface processes through mantle plume activity, forming large igneous provinces (LIPs) and some of the modern hotspot volcanoes5,6. Petrological7 and geodynamic8 evidence suggest a link between the formation of oceanic plateaus and the interactions of mantle plumes and mid-ocean ridges (MORs). Even though the causality relationship between both processes is still unclear (either rifting is initiated by plume impact or it …

Future Changes In Mean And Extreme Monsoon Precipitation In The Middle And Lower Yangtze River Basin, China, In The Cmip5 Models, Yanjuan Wu, Shuang-Ye Wu, Jiahong Wen, Felipe Tagle, Ming Xu, Jianguo Tan

Department of Earth, Environment and Sustainability Faculty Publications

In this study, the potential future changes of mean and extreme precipitation in the middle and lower Yangtze River basin (MLYRB), eastern China, are assessed using the models of phase 5 of the Coupled Model Intercomparison Project (CMIP5). Historical model simulations are first compared with observations in order to evaluate model performance. In general, the models simulate the precipitation mean and frequency better than the precipitation intensity and extremes, but still have difficulty capturing precipitation patterns over complex terrains. They tend to overestimate precipitation mean, frequency, and intensity while underestimating the extremes. After correcting for model biases, the spatial variation …

Plate Boundary Observatory And Related Networks: Gps Data Analysis Methods And Geodetic Products, Thomas A. Herring, Timothy I. Melbourne, Mark H. Murray, Michael A. Floyd, Walter M. Szeliga, Robert W. King, David A. Phillips, Christine M. Puskas, Marcelo Santillan, Lei Wang

All Faculty Scholarship for the College of the Sciences

The Geodesy Advancing Geosciences and EarthScope (GAGE) Facility Global Positioning System (GPS) Data Analysis Centers produce position time series, velocities, and other parameters for approximately 2000 continuously operating GPS receivers spanning a quadrant of Earth’s surface encompassing the high Arctic, North America, and Caribbean. The purpose of this review is to document the methodology for generating station positions and their evolution over time and to describe the requisite trade-offs involved with combination of results. GAGE GPS analysis involves formal merging within a Kalman filter of two independent, loosely constrained solutions: one is based on precise point positioning produced with the …

Birth And Evolution Of The Rio Grande Fluvial System In The Last 8 Ma:Progressive Downward Integration And Interplay Between Tectonics, Volcanism, Climate, And River Evolution, Marisa N. Repasch

Earth and Planetary Sciences ETDs

The Rio Grande-Rio Chama (RG-RC) fluvial system has evolved dramatically over the last 8 Ma, undergoing channel migrations, drainage capture and integration events, volcanic damming, and carving and refilling of paleocanyons. Volcanism concurrent with the development of the river system provides a unique opportunity to apply multiple geochronometers to the study of its incision and drainage evolution. This paper reports 19 new ⁴⁰Ar/³⁹Ar basalt ages and 19 detrital mineral samples (zircon and sanidine) collected from RG-RC alluvium overlain by dated basalt flows in the context of a compilation of published ⁴⁰Ar/³⁹Ar basalt ages. The …

Possible Recent Warming Hiatus On The Northwestern Tibetan Plateau Derived From Ice Core Records, Wenling An, Shugui Hou, Wangbin Zhang, Shuang-Ye Wu, Hao Xu, Hongxi Pang, Yetang Wang, Yaping Liu

Department of Earth, Environment and Sustainability Faculty Publications

Many studies have reported enhanced warming trend on the Tibetan Plateau (TP), even during the warming hiatus period. However, most of these studies are based on instrumental data largely collected from the eastern TP, whereas the temperature trend over the extensive northwestern TP remains uncertain due to few meteorological stations. Here we combined the stable isotopic δ¹⁸O record of an ice core recovered in 2012 from the Chongce glacier with the δ¹⁸O records of two other ice cores (i.e., Muztagata and Zangser Kangri) in the same region to establish a regional temperature series for the northwestern …

Geologic, Geochemical, And Geophysical Characterization Of The Gold Deposits Of The Horseshoe Bend Mining District, Idaho: Building A Four Dimensional Model For Ore Exploration, Joshua Ekhoff

Boise State University Theses and Dissertations

The Eocene aged Trans-Challis Fault System of central Idaho provides the tectonic and magmatic framework for a series of Au-Ag and Cu-Mo ore deposits. From its northernmost extension near Butte, Montana to its southwestern terminus in the Boise Basin of south-central Idaho the Trans-Challis Fault System is associated with some of the richest precious metal deposits found in Idaho. However, the southernmost tip of the Trans-Challis Fault System, composed of the Horseshoe Bend and Pearl mining districts, remains understudied, receiving little economic or academic attention. As a result, how the Pearl to Horseshoe Bend mining districts fit within the established …

Protracted Thrusting Followed By Late Rapid Cooling Of The Greater Himalayan Sequence, Annapurna Himalaya, Central Nepal: Insights From Titanite Petrochronology, Jesse Bennett Walters

Boise State University Theses and Dissertations

Temperature-time (T-t) paths derived from coupled Zr-in-titanite thermometry and U-Pb geochronology are useful for examining middle-crustal tectonic processes. T-t data collected from the titanite-bearing calcsilicates of the upper Greater Himalayan Sequence (GHS) along the Marsyandi River, Annapurna Himalaya, illustrate a significantly different metamorphic history than previously recorded in central Nepal. Combined with traditional thermobarometry, textural relationships, and field mapping, titanite T-t data reveal a protracted history of mid-crustal tectonics. Peak Zr-in-titanite temperatures are 750-850 °C at 10-14 kbar. T-t paths are divided into two groups, which are separated by the Chame Shear Zone (CSZ). Group I (upper) rocks show cooling …

2015 Gsa International Distinguished Lecturer Tours Key Locations In Central And South America, Lisa L. Ely

Geological Sciences Faculty Scholarship

As the International Lecturer from North America, I visited 11 destinations in Ecuador, Peru, Chile, Costa Rica, Mexico, and Puerto Rico. The tour was designed to include locations where the topic of my presentation, “Following in the Footsteps of Darwin:
Combining Geological and Historical Evidence to Assess Earthquakes and Tsunami Hazards,” would have direct relevance.

Discipline-Based Planetary Education Research And Computational Fluid Dynamics Analysis Of Mars, Filis Coba

Physics Theses & Dissertations

This thesis originates from the testing and implementation of an IRB-approved interactive animation designed to help students understand what causes The Reasons For The Seasons (RFTS) on Earth. Results from the testing indicated a small improvement in student understanding after exposure to the animation. Next, using the 3-D mapping tool Google Earth, students explored seasons and other planetary features on Mercury, Venus, the Moon and Mars through IRB-approved interactive tours which were developed and tested for astronomy education. Results from the tests indicated that there were statistically significant learning gains (p-value < 0.05) after students interacted with the tours compared to those who did not. The development of the tours inspired a geophysics study of the possibility of former plate motion (or plate tectonics) on Mars. A 2-D finite element convection model for the mantle of Mars was designed and solved using COMSOL Multiphysics 5.1, to investigate whether or not thermal gradients in a Mars-sized planet could cause vigorous upper mantle convection, consistent with plate tectonic processes. Results from this project indicated that stable convection could occur in the interior of a Mars-like planet assuming the presence of sufficiently high thermal gradients at about 0.8 times the mantle temperature of Earth. The convective patterns resembled hot upwelling and cool downwelling which may be similar to subduction-like features. Furthermore, increasing the temperature of the hot boundaries resulted in faster, more rigorous convective motions and a hotter average temperature.

Structure And Geochronology Of The White Fork Pluton, Southern Sierra Nevada, Ian Richard Mahaffey

Natural Resources Management and Environmental Sciences

The Sierra Nevada batholith represents an archetypal continental arc, although the style of deformation throughout the history of the arc is only poorly understood, in part due to the voluminous nature of Late Cretaceous magmatism that has overprinted earlier structures. The purpose of this study is to gain a better understanding of pre-Late Cretaceous deformation in the Sierra Nevada batholith through a structural and geochronological study of the Jurassic White Fork pluton. A Jurassic age for the White Fork pluton is indicated by its inclusion of numerous 148 Ma Independence dikes, and geochronology on the White Fork pluton is limited …

Quartz Crystal Preferred Orientation And Recrystallization Patterns From Naturally Deformed Rocks Under Constriction, Riley Quine

Materials Engineering

This study analyzes crystal preferred orientation (CPO) patterns within constrictional quartz-rich gneisses. Quartz deformation and CPO patterns are an area of interest because quartz is one of the most prevalent minerals in earth's crust. Understanding the typical way that quartz crystals reorient under different states of strain can provide geologists with an additional tool for understanding paleo-strain. Temperature and strain geometry are two dominant factors that control the orientation of quartz crystals within a rock. Temperature determines which slip planes are active and slip planes typically reorient so that they are perpendicular to maximum stress. Previous workers have suggested that …

The Influence Of The Great Falls Tectonic Zone On The Thrust Sheet Geometry Of The Southern Sawtooth Range, Montana, Usa, Caroline M. Burberry, J. M. Palu

Department of Earth and Atmospheric Sciences: Faculty Publications

The reactivation potential of pre-existing deep-seated structures influences deformation structures produced in subsequent compression. This contribution investigates thrust geometries produced in surface thrust sheets of the Sawtooth Range, Montana, USA, deforming over a previously faulted sedimentary section. Surface thrust fault patterns were picked using existing maps and remote sensing. Thrust location and regional transport direction was also verified in the field. These observations were used to design a series of analogue models, involving deformation of a brittle cover sequence over a lower section with varying numbers of vertical faults. A final model tested the effect of decoupling the upper cover …

The Spatial Distribution And Origins Of Sandstone Monoliths In The Swauk Watershed, Kittitas County, Wa, Rebeca Becerra, Daniel O'Dell

Symposium Of University Research and Creative Expression (SOURCE)

Large groups of gigantic sandstone and conglomerate monoliths populate the Swauk Watershed of northern Kittitas County. These monoliths rest on side slopes in the watershed and distinctively project from their surroundings. The origins of these features are unknown. We studied these monoliths in the field by mapping their spatial distribution, describing their morphology and composition, and measuring their orientation and sizes in order to determine their origins. We used Google Earth and topographic maps to locate the monoliths and map their distribution. Interpretations were based from field work data and past research. Our field results show commonalities between the features …

An Investigation Of Hydrogeologic, Stratigraphic, And Structural Controls On Acer Grandidentatum Communities In A Karst Landscape, Owl Mountain Province, Fort Hood Military Installation, Texas, Melinda S. Faulkner

Electronic Theses and Dissertations

The Owl Mountain Province is located within the Fort Hood Military Installation, an approximately 880 km2 installation established in the 1940s in Bell and Coryell counties, Texas, which has undergone extensive land use changes associated with military training, maintaining much of the vegetation in early succession. This study investigates thelithologic, stratigraphic, and structural controls on the hydrologic, hydrogeologic, and geomorphologic evolution of the Owl Mountain Province as expressed by mesic vegetation communities, including Pleistocene relicts Acer grandidentatum, within karst terrains. These systems exhibit complexly overprinted speleogenetic evolutions within a dynamic groundwater regime resulting from regional climate shifts throughout the …