Physical Sciences and Mathematics Commons^™

Collisional Reactivation Of Rift Margin Fracture Zones, Taiwan And The Taconic Allochthon, David C. Mirakian

Master's Theses

Chapter I. Transverse Topographic Development due to the Reactivation of a Partially-Subducted Fracture Zone: The Southwest Hsüehshan Range, Central Taiwan

Abstract — The southwest flank of the Hsüehshan Range is defined by a topographic break which cuts across regionally mapped structures in central Taiwan. The mountain front trends ~345°, slightly oblique to the Sanyi-Puli seismic zone which has been previously interpreted as a reactivated continental margin fracture zone. Structural data collected along the length of the topographic break reveal two populations of cross-cutting faults with distinct fault-zone materials and a series of southwest-plunging folds. Paleostress axes were reconstructed using the …

A Continuous Late Holocene Record Of Paleoclimate Change From Grinnell Lake Sediment Cores, Glacier National Park, Montana, Jonathan G. Griffith

Honors Theses

Grinnell Lake is a glacially-fed alpine lake in the northern Rocky Mountains of Montana. Limnological parameters and radiocarbon ages from a ~1.17 -meter-long sediment core from Grinnell Lake provide a ~1,200 year-long climate record. The objective of this thesis is to develop a multi-proxy record of glaciation by distinguishing periods of positive and negative mass balance chronologically. Two overlapping sediment cores (1P-1B-1 and 1C-2B-1) were described, photographed, and sampled at 0.5 cm, 1 cm, and 5 cm intervals and analyzed for % organic carbon, % inorganic carbon, mineral composition, bulk density, biogenic silica, and clastic sediment flux. Glacial fluctuations were …

Detrital Zircon Fission Track Ages Of The Paleocene Orca Group Of Eastern Prince William Sound Near Cordova Alaska, Tyler M. Izykowski

Honors Theses

The Prince William terrane is a major component of the Mesozoic-Tertiary accretionary complex of the North American Cordillera that is well exposed for ~2200 km in southern Alaska and is inferred to be one of the thickest accretionary complexes in the world. Detrital zircons from Prince William terrane record the thermal evolution and exhumation history of the accretionary wedge. Samples of the Paleocene-Eocene Orca Group of the Prince William terrane were analyzed using detrital zircon fission track techniques to understand the thermochronology of the region near Cordova. Six sandstones from the Orca Group and one sample of the Sheep Bay …

Geochemical And Petrographic Analysis Of Gore Mountain Garnets, Adirondacks Ny, Elizabeth R. Morgan

Honors Theses

The mine at Gore Mountain is famous for its giant garnets and long history of garnet abrasive production. This location, Warrensburg (Wall St.), and others were examined to attempt to better understand the petrogenesis of these remarkable rocks. Our studies have emphasized the geochemistry of bulk rocks and rock and mineral separates (122 analyses), thin section petrology, and thermodynamic modeling of mineral assemblages. At Gore Mtn. the ore has the assemblage hornblende-plagioclase-garnet-OPX-biotite, and formed over a ~2 m thick transition zone from a layered olivine corona gabbro, metamorphosed at granulite facies. Petrographically the delicate corona structures and fine-grained garnets were …

Mesozoic Burial, Mesozoic And Cenozoic Exhumation Of The Funeral Mountains Core Complex, Death Valley, Southeastern California, Mengesha Assefa Beyene

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Funeral Mountains of Death Valley National Park, CA, provide an opportunity to date metamorphism resulting from crustal shortening and subsequent episodic extensional events in the Sevier hinterland. It was not clear whether crustal shortening and thus peak temperature metamorphism in the hinterland of the Sevier-Laramide orogenic wedge have occurred whether in Late Jurassic, Early Cretaceous , Late Cretaceous or somewhere between. Particularly ambiguous is the timing of crustal shortening in the deep levels of the hinterland of the Sevier belt, now manifest in the metamorphic core complexes, and how and when these middle-to-lower crustal rocks were exhumed. A 6-point …

Lineament Mapping For Groundwater Exploration Using Remotely Sensed Imagery In A Karst Terrain : Rio Tanama And Rio De Arecibo Basins In The Northern Karst Of Puerto Rico, Carla A. Alonso-Contes

Dissertations, Master's Theses and Master's Reports - Open

Remote sensing and advanced digital image processing techniques were developed and tested for delineating karst features important for the subterranean hydrology in the Tanamá River and Rio Grande de Arecibo catchments located in the North Coast Tertiary Basin of Puerto Rico, where groundwater contributes to base flow for surface water bodies which in itself is the main supply of drinking water. This aquifer region is a karst platform of carbonate rocks and clastic beds, thought to comprise a confined aquifer beneath and an unconfined aquifer. Products derived from ASTER, Landsat (ETM+ and TM), a NED DEM (30 m), and a …

Geochemistry, Geothermobarometry And Geochronology Of High-Pressure Granulites And Implications For The Exhumation History Of Ultrahigh-Pressure Terranes: Dulan, Western China, Benjamin David Joseph Christensen

All Master's Theses

The Dulan ultrahigh-pressure (UHP) rocks of the North Qaidam terrane, Western China, represent continental crust that has been subducted ~100 km during continental collision. Adjacent granulites representing burial to ~50 km could either be overprinted eclogites or a separate high-pressure-high-temperature (HP-HT) granulite unit. Overprinted eclogites and HP-HT granulites imply different P-T-t paths for UHP rocks. Metamorphic conditions for the granulites are 750–880 °C and 14–17 kbar. Zircon U-Pb geochronology, REE patterns and Ti-in-zircon thermometry indicate an increase in temperature from ~800 °C (449 Ma) to ~900 °C (418 Ma). This temperature increase could explain the presence of granulite leucosomes and …

Relationships Between Snake River Paleofloods, Occupational Patterns And Archaeological Preservation At Redbird Beach Archaeological Site In Lower Hells Canyon, Idaho, Tabitha Trosper

All Master's Theses

The Snake River basin drains 282,000 km² of the northwestern U.S. and is the largest tributary to the Columbia River. Redbird Beach, an archaeological site located in the lower Hells Canyon reach of the Snake River, contains extensive vertical exposures of archaeological materials interbedded with Snake River flood sediments. Redbird Beach formed in the lee of the Redbird Creek debris fan, is composed of interfingering deposits from large floods on the Snake River and locally-derived alluvial sediments from Redbird Creek. Through stratigraphic analyses of slackwater deposits, this study compares the temporal and spatial patterns of human occupation at Redbird …