Thesis (M.S.)--Ohio University, November, 2006. / Title from PDF t.p. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 74-82).

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Η παρούσα εργασία πραγματεύεται την τεκτονική ανάλυση δύο μεγασκοπικών επωθήσεων στο βόρειο τμήμα της νήσου Κεφαλονιάς. Για την ανάλυση αυτών πάρθηκαν μετρήσεις με γεωλογική πυξίδα οι οποίες προβλήθηκαν σε στερεογραφικά δίκτυα για εξαγωγή συμπερασμάτων. Βάσει των μετρήσεων αυτών κατασκευάστηκαν δύο γεωλογικές τομές εγκάρσια στις επωθήσεις με σκοπό την απεικόνιση της λειτουργίας αυτών. Τονίζεται ότι τα παραπάνω παρουσιάζουν ορθή ερμηνεία μόνο σε συσχέτιση με υπαίθριες παρατηρήσεις. / The present work is a tectonic analysis of two major thrusts in the northern part of Kefalonia island. Measures were taken in the area with a geologic compass and then plotted in Schmidt diagramms. Presented are also two geologic cross sections perpendicular to the two thrusts.

Η γεωλογική εργασία αυτή έχει σκοπό τη χαρτογράφηση του Βορείου τμήματος, της νήσου Άνδρου μέσα από την αναγνώριση δομών. Ακόμη μέσα από την αναγνώριση των φάσεων παραμόρφωσης, αναλύονται τα εξελικτικά στάδια αυτής. Τέλος χρησιμοποιήθηκε το stereo 32 για την απεικόνιση δικτύων, όπου μέσα από αυτά οδηγηθήκαμε σε συμπεράσματα όσον αφορά τις διευθύνσεις στρωμάτων. / This geological paper has aim the mapping of Northern department,of the island Andros through the recognition of structures. Besides through the recognition of phases of deformity, are analyzed the evolutionary stages of the derfomity. Finally it was used stereo 32 for the depiction of networks, where through them we were led to conclusions with regard to the addresses of layers.

abstract: Understanding the structural evolution of planetary surfaces provides key insights to their physical properties and processes. On the Moon, large-scale tectonism was thought to have ended over a billion years ago. However, new Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) high resolution images show the Moon’s surface in unprecedented detail and show many previously unidentified tectonic landforms, forcing a re-assessment of our views of lunar tectonism. I mapped lobate scarps, wrinkle ridges, and graben across Mare Frigoris – selected as a type area due to its excellent imaging conditions, abundance of tectonic landforms, and range of inferred structural controls. The distribution, morphology, and crosscutting relationships of these newly identified populations of tectonic landforms imply a more complex and longer-lasting history of deformation that continues to today. I also performed additional numerical modeling of lobate scarp structures that indicates the upper kilometer of the lunar surface has experienced 3.5-18.6 MPa of differential stress in the recent past, likely due to global compression from radial thermal contraction. Central pit craters on Mars are another instance of intriguing structures that probe subsurface physical properties. These kilometer-scale pits are nested in the centers of many impact craters on Mars as well as on icy satellites. They are inferred to form in the presence of a water-ice rich substrate; however, the process(es) responsible for their formation is still debated. Previous models invoke origins by either explosive excavation of potentially water-bearing crustal material, or by subsurface drainage of meltwater and/or collapse. I assessed radial trends in grain size around central pits using thermal inertias calculated from Thermal Emission Imaging System (THEMIS) thermal infrared images. Average grain size decreases with radial distance from pit rims – consistent with pit-derived ejecta but not expected for collapse models. I present a melt-contact model that might enable a delayed explosion, in which a central uplift brings ice-bearing substrate into contact with impact melt to generate steam explosions and excavate central pits during the impact modification stage. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2016

abstract: The collision of India and Eurasia constructed the Himalayan Mountains. Questions remain regarding how subsequent exhumation by climatic and tectonic processes shaped the landscape throughout the Late Cenozoic to create the complex architecture observed today. The Mount Everest region underwent tectonic denudation by extension and bestrides one of the world’s most significant rain shadows. Also, glacial and fluvial processes eroded the Everest massif over shorter timescales. In this work, I review new bedrock and detrital thermochronological and geochronological data and both one- and two-dimensional thermal-mechanical modeling that provides insights on the age range and rates of tectonic and erosional processes in this region. A strand of the South Tibetan detachment system (STDS), a series of prominent normal-sense structures that dip to the north and strike along the Himalayan spine, is exposed in the Rongbuk valley near Everest. Using thermochronometric techniques, thermal-kinematic modeling, and published (U-Th)/Pb geochronology, I show exhumation rates were high (~3-4 mm/a) from at least 20 to 13 Ma because of slip on the STDS. Subsequently, exhumation rates dropped drastically to ≤ 0.5 mm/a and remain low today. However, thermochronometric datasets and thermal-kinematic modeling results from Nepal south of Everest reveal a sharp transition in cooling ages and exhumation rates across a major knickpoint in the river profile, corresponding to the modern-day Himalayan rainfall transition. To the north of this transition, exhumation histories are similar to those in Tibet. Conversely, < 3 km south of the transition, exhumation rates were relatively low until the Pliocene, when they increased to ~4 mm/a before slowing at ~3 Ma. Such contrasting exhumation histories over a short distance suggest that bedrock exhumation rates correlate with modern precipitation patterns in deep time, however, there are competing interpretations regarding this correlation. My work also provides insights regarding how processes of glacial erosion act in a glacio-fluvial valley north of Everest. Integrated laser ablation U/Pb and (U-Th)/He dating of detrital zircon from fluvial and moraine sediments reveal sourcing from distinctive areas of the catchment. In general, the glacial advances eroded material from lower elevations, while the glacial outwash system carries material from higher elevations. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2017

We present crustal velocities for 29 continuously recording GPS stations from the southern central Andes across the Puna, Eastern Cordillera, and Santa Barbara system for the period between the 27 February 2010 Maule and 1 April 2014 Iquique earthquakes in a South American frame. The velocity field exhibits a systematic decrease in magnitude from similar to 35mm/yr near the trench to <1mm/yr within the craton. We forward model loading on the Nazca-South America (NZ-SA) subduction interface using back slip on elastic dislocations to approximate a fully locked interface from 10 to 50km depth. We generate an ensemble of models by iterating over the percentage of NZ-SA convergence accommodated at the subduction interface. Velocity residuals calculated for each model demonstrate that locking on the NZ-SA interface is insufficient to reproduce the observed velocities. We model deformation associated with a back-arc decollement using an edge dislocation, estimating model parameters from the velocity residuals for each forward model of the subduction interface ensemble using a Bayesian approach. We realize our best fit to the thrust-perpendicular velocity field with 705% of NZ-SA convergence accommodated at the subduction interface and a slip rate of 9.10.9mm/yr on the fold-thrust belt decollement. We also estimate a locking depth of 149km, which places the downdip extent of the locked zone 13520km from the thrust front. The thrust-parallel component of velocity is fit by a constant shear strain rate of -19x10(-9)yr-(1), equivalent to clockwise rigid block rotation of the back arc at a rate of 1.1 degrees/Myr.

Uranium-lead (U-Pb) geochronology and Hafnium (Hf) isotope geochemistry of detrital zircons of the Harmony Formation of north central Nevada provide new insights into the tectonic evolution of the Late Paleozoic western Laurentian margin. Using laser-ablation inductively coupled plasma mass spectrometry, 10 arenite samples were analyzed for U-Pb ages, and 8 of these samples were further analyzed for Hf isotope ratios. Three of the sampled units have similar U-Pb age peaks and Hf isotope ratios, including a 1.0-1.4Ga peak with epsilon Hf values of +12 to -3 and a 2.5-2.7Ga peak with epsilon Hf values of +7 to -5. The remaining seven samples differ significantly from these three, but are similar to one another; having age peaks of 1.7-1.9Ga with epsilon Hf of +10 to -20 and age peaks of 2.3-2.7Ga with epsilon Hf of +6 to -8. The data confirm the subdivision of the Harmony Formation into two petrofacies: quartzose (Harmony A) and feldspathic (Harmony B). The three samples with 1.0-1.4 and 2.5-2.7Ga peaks are the Harmony A, which originated in the central Laurentian craton. The other seven samples are the Harmony B, which originated in eastern Alberta-western Saskatchewan, north of the Harmony A source. We propose that all Harmony Formation strata were deposited near eastern Alberta and subsequently tectonically interleaved with Roberts Mountains allochthon strata. We interpret that the entire package was tectonically transported south along the western Laurentian margin and then emplaced eastward onto the craton during the Late Devonian-Early Mississippian Antler orogeny.

Quaternary landform features and their associated sedimentary assemblages (river terraces and alluvial fans) often provide important records of long-term landscape evolution. The reconstruction of global terrace sequences has enabled the identification of numerous external and internal forcing mechanisms which operate within the Quaternary landscape system. The relative effects of these forcing mechanisms are highly variable over a range of spatial and temporal scales. In this research, a combined study approach is adopted in order to ascertain the significance of external (e.g. tectonics, climate) and/or internal (e.g. lithological thresholds) forcing mechanisms upon patterns of Quaternary landscape development within the Tabernas Basin, SE Spain. The results of extensive field investigation have developed a four-tiered landform stratigraphy (i.e. basin wide terrace levels) for the Tabernas Basin. Chronological constraints for the Quaternary stratigraphy were obtained from Optically Stimulated Luminescence dating. Age estimations develop a pattern of climatically driven terrace aggradations during glacial phases throughout the Middle to Late Pleistocene. This pattern fits well with regional models of enhanced terrace formation during glacial phases after the Middle Pleistocene. The Quaternary stratigraphy of the Tabernas Basin was investigated by methods of geospatial interpolation and numerical modelling. The results of conceptual and quantitative modelling approaches highlight the dominance of non-uniform rates of base-level change driven by variable rates of tectonic uplift throughout the Mid-Late Pleistocene. Enhanced uplift in the west of the basin associates well with regional patterns, with tectonically driven base-level changes focused in the eastern Alpujarran Corridor. Internal landscape thresholds were important in the Holocene development of the Tabernas basin. Increased rates of incision in the final stages of basin development were likely attributed to the effects of lithological controls coupled with anthropogenic activity in the basin catchment.