Tectonics and Structure Commons^™

Glacier Slip And Seismicity Induced By Surface Melt, Peter L. Moore, J. Paul Winberry, Neal R. Iverson, Knut A. Christianson, Sridhar Anandakrishnan, Miriam Jackson, Mark E. Mathison, Denis Cohen

All Faculty Scholarship for the College of the Sciences

Many of the key processes governing fast glacier flow involve interaction between a glacier and its basal hydrological system, which is hidden from direct observation. Passive seismic monitoring has shown promise as a tool for remotely monitoring basal processes, but lack of glacier-bed access prevents clear understanding of the relationships between subglacial processes and corresponding seismic emissions. Here we describe direct measurements of basal hydrology, sliding, and broadband seismicity made in a unique subglacial facility in Norway during the onset of two summer melt seasons. In the most pronounced of these episodes, rapid delivery of surface meltwater to the bed …

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 …

An Apparent Angular Unconformity In Western Connecticut, Stanley Schleifer, Nazrul I. Khandaker, Adisa Charles, Hernando Martinez, Shirley Jackson, Chiemeka Ihebom

Publications and Research

The recent extension, to the north, of the U. S. Route 7 ‘superhighway’ in the town of Brookfield, Connecticut has involved the excavation of crystalline bedrock of lower Paleozoic to upper Proterozoic age in the area. The road cuts produced by this excavation have exposed some interesting features of structure and lithology. An outcrop, observed by the authors off the east side of route 7, at grid coordinates 41.482444 N, 73.415307 W is of particular interest. It appears, to the casual observer to be an angular unconformity. Maps and publications regarding this area of Western Connecticut support the likelihood of …

Late Holocene Tsunami Deposits At Salt Creek, Washington, Usa, Ian Hutchinson, Curt D. Peterson, Sarah L. Sterling

Anthropology Faculty Publications and Presentations

We interpret two thin sand layers in the estuarine marsh at Salt Creek, on the southern shore of the Strait of Juan de Fuca, as the products of tsunamis propagated by earthquakes at the Cascadia subduction zone. The sand layers extend for about 60 m along the left bank of the creek about 800 m from the mouth, and can be traced to the base of a nearby upland area. One layer is exposed in the creek bank about 400 m further upstream, but they are only patchily distributed in the rest of the central area of the marsh. Both …

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 …

Geometry And Evolution Of Fold Structures Within The High Folded Zone: Zagros Fold-Thrust Belt, Kurdistan Region, Iraq, Mjahid Zebari

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

Understanding the deformation style within the Zagros Fold-Thrust Belt is crucial for understanding the convergence between the colliding Arabian and Eurasian plates and nature of structures that trap hydrocarbons within the belt. The Zagros Fold-Thrust Belt has propagated ~250 km southwest-ward in Northern Iraq. In this study, deformation style of a number of fault-related folds within a part of the belt has been considered. The research intends to understand the geometry and formation mechanisms of these folds, via constructing models for the deformation geometry of folds and associated thrusts at depth using field data and seismic lines and detecting their …

Insights Into The Timing, Origin, And Deformation Of The Highland Mountains Gneiss Dome In Southwestern Montana, Usa, Lane Markes Boyer

Graduate Theses and Dissertations

The Highland Mountains of southwestern Montana offer a unique view of the Archean igneous and metamorphic rocks within the Great Falls tectonic zone (GFTZ). A Paleoproterozoic structural gneiss dome has been interpreted in the southern extent of the Highland Mountains. The ∼ 130km² of exhumed metamorphic rocks and gneiss dome exposed in the Highland Mountains are the primary focus of this research. The formation of the Highland Mountains gneiss dome is proposed to be directly related to a northwest-side down detachment (the Steels Pass shear zone) that formed during terrane collision along the GFTZ. The field investigation determined foliation …

Incision History Of Glenwood Canyon, Colorado, Usa, From The Uranium-Series Analyses Of Water-Table Speleothems, Victor J. Polyak, Harvey R. Duchene, Donald G. Davis, Arthur N. Palmer, Margaret V. Palmer, Yemane Asmerom

International Journal of Speleology

Uranium-series analyses of water-table-type speleothems from Glenwood Cavern and “cavelets” near the town of Glenwood Springs, Colorado, USA, yield incision rates of the Colorado River in Glenwood Canyon for the last ~1.4 My. The incision rates, calculated from dating cave mammillary and cave folia calcite situated 65 and 90 m above the Colorado River, are 174 ± 30 m/My for the last 0.46 My and 144 ± 30 m/My for the last 0.62 My, respectively. These are consistent with incision rates determined from nearby volcanic deposits. In contrast, δ²³⁴U model ages (1.39 ± 0.25 My; 1.36 ± 0.25 …

Microstructures And Quartz Lattice-Preferred Orientations In The Eclogite-Bearing Migmatitic Gneisses Of The D’Entrecasteaux Islands, Papua New Guinea, T. A. Little, B. R. Hacker, S. J. Brownlee, G. Seward

Environmental Science and Geology Faculty Research Publications

Lattice preferred orientations (LPO) of quartz in gneiss domes of the D’Entrecasteaux Islands, Woodlark Rift shed insight into exhumation of the world’s youngest (~5–7Ma) eclogite-bearing terrane at cm/yr rates. We focus on deformation that affected the terrane as it transited between lower crustal depths and the surface, including: (1) grain-scale deformation mechanisms; and (2) style of flow and mode of emplacement of the domes. Electron-backscatter diffraction was used to analyze microstructure and LPOs of 37 quartzofeldspathic gneiss samples that enclose meter-scale mafic blocks preserving original eclogite-facies assemblages. During exhumation of the ultrahigh-pressure (UHP) terrane, gneisses were retrogressed in the amphibolite …

A Study Of Knickpoint Formation: Geomorphic Analysis Of San Simeon Creek, Keith Moffatt

Natural Resources Management and Environmental Sciences

The highest point of orogeny in the Santa Lucia range occurs 50-60km from the nearest active faulting. This orogeny is believed to have occurred hear due to relatively weak Franciscan Mélange versus the granitic material at the fault boundary. This paper studies the development of a knickpoint in San Simeon creek to identify the role of relatively recent (graded time) tectonic activity in orogeny of the Santa Lucia range.
The 2003 earth quake is evidence of recent base level change with the occurrence of orogeny supporting the theory of continuous orogeny in recent and graded time scale. Although the knickpoint …

Detrital Zircon U/Pb Age Determination: Understanding The Provenance Of The Upper Cretaceous Shumagin Formation, Alaska, Carly F. Roe

Lawrence University Honors Projects

The tectonic evolution of the Chugach-Prince William Terrane (CPW), an accretionary complex along the southern Alaskan margin, has been the subject of much debate. There are two prevailing hypotheses for the location of the CPW at the time of its intrusion by the plutons of the Sanak-Baranof belt, and both require distinctly different source regions for the sediment of the CPW flysch. Therefore, a better understanding of the provenance of these sediments will help constrain the location of the CPW at the time of the deposition of its sediments. This study presents an analysis of new U/Pb detrital zircon, mineralogical …

Investigating The Paradigms Of Sikkim’S Built Environment, Bennet Song

Independent Study Project (ISP) Collection

The region of Sikkim is located on the Aplide-Himalayan global seismic belt, a seismically vulnerable area of the world. The 2011 M6.9 earthquake caused a severe disruption in the functions of both rural and urban Sikkim. In areas populated by humans, most of the visible damage and harm done in an earthquake is due to poorly designed and constructed buildings and infrastructure rather than the earthquake itself. The focus of this paper lies in study of the relationship between the predominant building types of rural vs. urban Sikkim. Ikra is a low cost vernacular building type found in Sikkim’s rural …

Alluvial Sediment Or Playas: What Is The Dominant Source Of Sand And Silt In Desert Soil Vesicular A Horizons, Southwest Usa, Mark R. Sweeney, Eric V. Mcdonald, Christohper E. Markley

All Faculty Scholarship for the College of the Sciences

Vesicular A (Av) soil horizons form beneath desert pavements from the accretion of aeolian sediment (dust) commonly thought to be derived primarily from desiccating pluvial lakes and playas, with contributions from ephemeral washes and alluvial fans. Particle size distributions of Av horizons are typically bimodal with primary modes of very fine silt and fine sand, suggesting that the horizon matrix is derived from multiple sources. Here we conduct detailed chemical and physical analysis of both Av horizon soil samples and potential sources of aeolian sediment to better constrain the relative contributions of dust associated with the development of Av horizons. …

2012 Haida Gwaii Quake: Insight Into Cascadia's Subduction Extent, Walter Szeliga

Geological Sciences Faculty Scholarship

The limits of Cascadia were first defined to contain nearly the entire margin of the Pacific Northwest, from Cape Mendocino through the Alaska Panhandle [Schuchert, 1910; Schuchert and Barrell, 1914]. Since that time, the boundary of Cascadia has shrunk to become essentially synonymous with the region where the Juan de Fuca plate subducts beneath the North American plate. As a consequence, seismic hazard assessments in the Pacific Northwest have conventionally focused on the potential for large megathrust earthquakes along the interface of the Juan de Fuca and North American plates.

Nucleation And Seismic Tremor Associated With The Glacial Earthquakes Of Whillans Ice Stream, Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Douglas A. Wiens, Richard B. Alley

All Faculty Scholarship for the College of the Sciences

The ability to monitor transient motion along faults is critical to improving our ability to understand many natural phenomena such as landslides and earthquakes. Here, we usedata from a GPS and seismometer network that were deployed to monitor the regularly repeating glacial earthquakes of Whillans Ice Stream, West Antarctica to show that a unique pattern of precursory slip precedes complete rupture along the bed of the ice stream. Additionally, we show that rupture can be independently tracked by increased levels of microseismic activity, including harmonic tremor, that are coincident with the onset of slip at any location, thus providing a …

Anchored Sheet Pile Wall Design In Expansive Soils, Ömer Bilgin, Eman Mansour

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Expansive soils cause damage to civil engineering structures in various parts of the world, because they swell when absorb water and shrink when dry out. Due to swelling pressures, retaining walls can be subjected to additional lateral pressures causing increased wall deformations and bending moments. Anchor forces can also increase, if the walls are anchored. When expansive soils are present behind retaining walls, swell pressures should also be considered during design in addition to the traditional lateral earth pressures. This study proposes a method to predict potential swell pressures acting on retaining walls for use in design of these walls. …

Pliocene Sinistral Slip Across The Adobe Hills, Eastern California-Western Nevada: Kinematics Of Fault Slip Transfer Across The Mina Deflection, Sarah Nagorsen-Rinke, Jeffrey Lee, Andrew Calvert

All Faculty Scholarship for the College of the Sciences

The Adobe Hills region (California and Nevada, USA) is a faulted volcanic field located within the western Mina deflection, a right-stepping zone of faults that connects the northern Eastern California shear zone (ECSZ) to the south with the Walker Lane belt (WLB) to the north. New detailed geologic mapping, structural studies, and ⁴⁰Ar/³⁹Ar geochronology in the Adobe Hills allow us to calculate fault slip rates and test predictions for the kinematics of fault slip transfer into the Mina deflection. The Adobe Hills are dominated by Pliocene tuffaceous sandstone, basaltic lavas that yield ⁴⁰Ar/³⁹Ar ages …

Strain Energy Release From The 2011 9.0 Mw Tōhoku Earthquake, Japan, Kenneth M. Cruikshank, Curt D. Peterson

Geology Faculty Publications and Presentations

The purpose of this paper is to compare the strain energy released due to elastic rebound of the crust from the tragic 2011 9.0 Mw Tōhoku earthquake in Japan with the observed radiated seismic energy. The strain energy was calculated by analyzing coseismic displacements of 1024 GPS stations of the Japanese GEONET network. The value of energy released from the analysis is 1.75 × 1017 J, which is of the same order of magnitude as the USGS-observed radiated seismic energy of 1.9 × 1017 Nm (J). The strain energy method is independent of seismic methods for determining the energy released …

Paleoseismologic Evidence For Holocene Activity On The Pinto Mountain Fault, Twentynine Palms, California, Ana Maria Cadena

All Master's Theses

Excavations across the Pinto Mountain fault in Twentynine Palms, California exposed faulted strata across a 32-m wide zone. Trench wall exposures revealed clear evidence for five ground-rupturing events during the Holocene, and two additional events in the late Pleistocene. Optically stimulated luminescence ages from alluvial sediments suggest that the most recent event occurred between 1.7-2.9 ka B.P. and the penultimate event between 2.7-4.2 ka B.P.. Prior to the penultimate event, there were five ground-rupturing earthquakes on the eastern Pinto Mountain fault between 3.5-13.6 ka B.P.. The average recurrence interval since 13.3-13.6 ka B.P. is 1510-1680 years, and 1200-1500 years in …