Geology Commons^™

An Integrated Study Of The South-Central Part Of The Springerville Volcanic Field; The Final Piece, Marissa Mnich

Masters Theses 1911 - February 2014

The Springerville Volcanic Field (SVF) is a monogenetic volcanic field located in east-central Arizona and is the southernmost of several late Pliocene to Holocene volcanic fields along the margin of the Colorado Plateau. It encompasses an area of over 3000 km² and consists of over 450 vents, most of which are cinder cones, which produced mainly basaltic flows, between 2.1 and 0.3 Ma. About 85% of the SVF was previously mapped in detail by Condit, Crumpler and Aubele (1999). In the summers of 2010 and 2011, mapping was completed in the remaining portion of the field known as the …

Holocene Paleo-Environmental Variability Reconstructed From A Lake Sediment Record From Southeast Greenland, Gregory A. De Wet

Masters Theses 1911 - February 2014

Arctic climate variability over the Holocene has been both extensive and, at times, abrupt. Current understanding of these changes is still quite limited with few high-resolution paleoclimate records available for this period. In order to place observed and predicted 21^st century climate change in perspective, reliable and highly resolved paleo-reconstructions of Arctic climate are essential. Using an 8.5 m sediment core from Nanerersarpik Lake, this project will characterize climate changes during the Holocene, including the deglacial transition, the rapid changes that are known to have occurred around 8,200 years ago, the transition from Holocene thermal maximum (HTM) to the …

7700 Years Of Holocene Climatic Variability In Sermilik Valley, Southeast Greenland Inferred From Lake Sediments, Samuel H. Davin

Masters Theses 1911 - February 2014

During the latter half of the 20^th century until present day there has been an unprecedented rise in global annual mean temperatures accompanied by rising sea levels and a decrease in Northern Hemisphere snow cover, which if it continues will lead to widespread disruption of climate patterns, ecosystems, and present-day landscapes. It is therefore of critical importance to establish an expanded network of paleoclimate records across the globe in order to better assesses how the global climate system has changed in the past, that we may create a metric by which to address modern change. Herein is presented a7,700 …

Deciphering The Age And Significance Of The Cora Lake Shear Zone: Athabasca Granulite Terrane, Northern Saskatchewan, Sean P. Regan

Masters Theses 1911 - February 2014

Interpreting the tectonic significance of high strain zones requires detailed knowledge of the P-T-t-D history of rocks on either side and of tectonized rocks within the shear zone. In-situ monazite geochronology is particularly useful because it generates a time-integrated framework of metamorphism and fabric development. This can be achieved by correlating monazite compositional domains with the growth and consumption of major phases. Furthermore, monazite can be a fabric forming mineral, and can be directly linked to structural fabrics and kinematics. The Cora Lake shear zone (CLsz) represents a major lithotectonic discontinuity within the deep crustal Athabasca Granulite terrain, and preserves …

Biomarker And Sedimentological Investigations Of Mis 8 Through Mis 12 From Lake El'gygytgyn, Ne Arctic Russia, Jeremy H. Wei

Masters Theses 1911 - February 2014

Abstract

Multiple proxy analysis of lake sediment records are crucial for understanding changes in environmental and climate conditions over historical and geological time. Most recently, the use of biomarker proxies coupled with sedimentological investigations provides a new approach for gaining insight into the lake processes that capture information about past climate change. This approach is applied here to better understand the paleoclimate record from Lake El’gygytgyn in Western Beringia. Multiple organic geochemical compound concentrations were measure as proxies for both aquatic and terrestrial biological productivity. Measurements of n-alkane (plant leaf waxes) as well as concentrations of the compounds arborinol …

How Does Hydropeaking Alter The Hydrology Of A River Reach? A Combined Water Budget, Modeling, And Field Observation Study. Deerfield River, Massachusetts, Brian C. Yellen

Masters Theses 1911 - February 2014

Hydroelectric releases on the Deerfield River in northwestern Massachusetts affect surface water-groundwater interactions there by daily reversing the head gradient between river and groundwater. Artificially elevated stage drives river water into the riparian aquifer. Water budget analysis indicates that roughly 10% of this bank-stored water is permanently lost from the river system in a 19.5 km reach, likely as a result of transpiration by bank vegetation.

Field observations as well as two-dimensional modeling results show that water losses are not uniform throughout the study reach. Riparian aquifer transmissivity in river sub-reaches largely determines the magnitude of surface water-groundwater exchange as …

Evolution Of Volatile Content Of The Parent Magma Of The 1875 Eruption Of Askja Volcano, Iceland, Heather A. Clark

Masters Theses 1911 - February 2014

The bulk of the eruption of Askja in north central Iceland on March 28-29 1875 consisted of a plinian eruption that lasted 6-7 hours, produced 0.2 km³ of ash and rhyolitic pumice, and created a surge and partially welded ash/pumice fall deposit that crops out on the shore of the modern caldera lake (Sparks et al. 1981). We evaluate the volatile budget of the magma during the eruption and focus on water concentration in glass fragments and shards, glass adjacent to crystals, and melt inclusions (MIs). Sparks et al. (1981) estimated the gas exit velocity at the vent was …

A Paleoclimate Modeling Experiment To Calculate The Soil Carbon Respiration Flux For The Paleocene-Eocene Thermal Maximum, David M. Tracy

Masters Theses 1911 - February 2014

The Paleocene-Eocene Thermal Maximum (PETM) (55 million years ago) stands as the largest in a series of extreme warming (hyperthermal) climatic events, which are analogous to the modern day increase in greenhouse gas concentrations. Orbitally triggered (Lourens et al., 2005, Galeotti et al., 2010), the PETM is marked by a large (-3‰) carbon isotope excursion (CIE). Hypothesized to be methane driven, Zeebe et al., (2009) noted that a methane based release would only account for 3.5°C of warming. An isotopically heavier carbon, such as that of soil and C3 plants, has the potential to account for the …

Characterization Of Damage Zones Associated With Laboratory Produced Natural Hydraulic Fractures, Erin Bradley

Masters Theses 1911 - February 2014

Both joint sets and fault-related fractures serve as important conduits for fluid flow. In the former case, they can strongly influence both permeability and permeability anisotropy, with implications for production of water, hydrocarbons and contaminant transport. The latter can affect issues of fluid flow, such as whether a given fault seals or leaks, and fault mechanics. These fractures are commonly interpreted as Natural Hydraulic Fractures (NHFs), i.e., mode 1 fractures produced when pore fluid pressure exceeds the tensile strength of the rock. Various mathematical models have been a rich source of hypotheses to explain the formation and propagation of NHFs, …

Fractures Of The Dammam Dome Carbonate Outcrops: Their Characterization, Development, And Implications For Subsurface Reservoirs, Mohammed M. Al-Fahmi

Masters Theses 1911 - February 2014

The exposed Tertiary carbonates of the Dammam Dome present an opportunity to study fractures in outcrops within the oil-producing region of Eastern Saudi Arabia. The study focuses on: 1) the characterization of fractures, 2) interpretation of their fracturing mechanism, and 3) the implications for the deep carbonate reservoirs of the Dammam Dome. The characterization of the outcrop fractures is integrated with structural analysis of the near-surface horizons mapped from reflection seismic and well data. Fractures are observed within all exposed carbonate units, but predominantly within the widely exposed Middle Rus unit. The fractures are opening-mode, bed-bound joints that form orthogonal …

A High-Resolution Temperature Record From Lakes Of The Lofoten Islands, Northwestern Norway Based On A New Uk37 Temperature Calibration From In Situ Measurements, Xiaohui Huang

Masters Theses 1911 - February 2014

Water filters and sediment trap samples were collected weekly from late May to early September 2009 from four lakes of the Lofoten archipelago, northwestern Norway, and were used to explore the applicability of the alkenone unsaturation index (UK37) for temperature reconstruction in limnic systems in the area. For the first time, we observed the occurrence of long-chain alkenones (LCAs) within the water columns of lakes in this region. Water filters from two of the four studied lakes contained measurable concentrations of alkenones that were restricted to spring turnover and disappeared with the onset of summer stratification. These results indicate that …

Jarosite Formation At The Davis Mine, Rowe, Massachusetts, Karen S. Miller

Masters Theses 1911 - February 2014

This study investigates jarosite formation and stability patterns at the abandoned Davis Pyrite Mine in Rowe, Massachusetts. Jarosite, an iron-sulfate hydroxide, is found in acid mine drainage (AMD) environments, in acid sulfate soils, and on Mars. Jarosite and the iron oxides goethite and hematite are present at the site. Soil samples from the site were examined by XRD, SEM, and EDS. Five mineralogical areas were found, based on mineral abundance patterns. Jarosite exists in four of these areas. Two jarosite morphologies were identified. “Variable” jarosite, with partly-dissolved crystals of about 0.5 to 5 micrometers diameter, exists in spoil pile samples. …

A Speleothem-Based High Resolution Reconstruction Of Climate In Southeastern Brazil Over The Past 4,100 Years, Brandon L. Taylor

Masters Theses 1911 - February 2014

Isotopic investigations of speleothem CR1 from Cristal Cave in southeastern Brazil have established a high-resolution record of climate change extending 4,100 years prior to sample collection in 2007. A total of 14 subsamples were collected from CR1 for U/Th age determination. ICP-MS analysis yielded very precise ages with analytical errors (2σ) averaging ± 13 years. An initial growth rate of .062 mm y-1 for the first 2860 years is followed by a rate of .08 mm y-1 for the remaining growth period allowing for sampling of δ18O at sub-decadal resolution. Stable isotope analyses show a large range of δ18O values …

The Distribution, Composition, And Formation Of Sahara Desert Microbialites From The Base Of The Meski Plateau, Outside Erfoud, Morocco, Sean Faulkner

Masters Theses 1911 - February 2014

Seven distinctly different museum-quality concretionary morphotypes of elongate, spheroidal, banded, botryoidal, columnar, rosette, and speleothem in regolith at two small sites at the base of the Meski Plateau near Erfoud, Morocco are described. Although most are isolated hand samples, the largest concretions are meter-sized blocks. Not one sample resembles any surrounding outcrop or bedrock. The barite rosettes formed first via periodic mixing of Ba2+/SO42- saturated solutions. They provided nuclei for cyclical precipitation-based concentric concretion development. The speleothem formed via precipitation from a carbonate-saturated solution in a large void within porous sandstone. The sand concretions formed when calcite precipitated around grains …

Exploring Isotopic Signatures Of Lake El'gygytgyn Sediments For Evidence Of Anoxia And Methane Cycling Over The Past 50,000 Years, Addie R. Holland

Masters Theses 1911 - February 2014

Compound specific isotope analysis of lake sediments is a powerful tool in deciphering evidence of changing climatic and paleoenvironmental conditions through time. Isotopic analysis of Lake El’gygytgyn pilot sediment cores, PG1351 and LZ1029, have contributed increased insight into paleoenvironmental interpretations regarding conditions of permanent ice cover and water column anoxia at the lake over the past 250 kyr. Bulk sediment δ15N was measured as a proxy for denitrification and a possible indicator for water column anoxia intensity. However, it appears that insufficient quantities of water column nitrate to fuel denitrification make its correlation with anoxia intensity ineffective. In pilot core …

Understanding The Depth And Nature Of Flow Systems In The Nashoba Terrane, Eastern Massachusetts, U.S.A., John P. Diggins

Masters Theses 1911 - February 2014

Igneous and metamorphic rock units have long been considered marginal aquifers yet they are a significant source for potable drinking water in many areas worldwide. Additionally, use of these systems is on the rise due to many factors including, contamination and overuse of surficial systems, as well as expanding population and drought. The Nashoba Terrane is a fault-bounded block of high-grade, steeply dipping metavolcanic and metasedimentary rock located in eastern Massachusetts, U.S.A. The Nashoba is northeast trending, extending from Oxford, MA to the Gulf of Maine south of Newburyport, MA. Seventeen previously drilled wells throughout the Nashoba were selected for …

Three-Dimensionally Preserved Arthropods From The Cambrian (Furongian) Of Quebec And Wisconsin: Systematics, Phylogeny, Ichnology, And Taphonomy, Joseph H. Collette

Masters Theses 1911 - February 2014

Three new types of arthropod from Cambrian intertidal lithofacies of the Elk Mound Group and Lodi Member of Wisconsin, and the Potsdam Group of Quebec are described. These arthropods are preserved ventrally in three dimensions – allowing detailed characterization of morphology. Arenocaris inflata, from the Furongian Elk Mound Group and St. Lawrence Formation, is the earliest occurrence of a phyllocarid. Mosineia macnaughtoni, a large (>10 cm long) euthycarcinoid arthropod, also occurs in Elk Mound strata. Mictomerus melochevillensis represents a new family of early euthycarcinoids, and is a large (8–10+ cm long) arthropod with eleven pairs of homopodous, uniramous limbs. …

Using The Oxidation State Of Iron Plagioclase To Evaluate Magma Oxygen Fugacity: A Micro-Xanes Study, Don Lac

Masters Theses 1911 - February 2014

No abstract provided.

Environmental Reconstructions From Laminated Lake Sediments, Lake C3, Ellesmere Island, Canadian High Arctic, Kathryn S. Zalzal

Masters Theses 1911 - February 2014

Sediments in Lake C3, Ellesmere Island, Canada, contain annual laminations, providing a record of sediment accumulation for 1900+ years. Marine sediments are also present at base of cores, recording lake isolation following isostatic rebound of the Taconite Inlet region in the mid-Holocene. Beyond weak correlations with snowfall and summer temperature and precipitation, varve thickness comparisons with instrumental data were largely unsuccessful, likely due to turbidite-induced erosion. However, summer climate conditions are of key importance in varve thicknesses at many Arctic sites and we expect this to be true at Lake C3. Trends in the thickness record also correspond in approximate …

Effects Of Anthropogenic Stage Fluctuations On Surface Water/Ground Water Interactions Along The Deerfield River, Massachusetts., Brandon J. Fleming

Masters Theses 1911 - February 2014

Understanding the connection of surface waters to ground-water systems is important when evaluating potential water resources. In the past surface waters and ground-water have been viewed as two different sources of water but more commonly now they are viewed as one connected resource (Winter et al, 1998). The nature of connection between surface and ground-waters varies depending on climatic and geologic settings, as well as anthropogenic influences such as ground-water pumping and manipulation of river flows by dams. This thesis takes advantage of daily stage changes in the Deerfield River to investigate surface water interactions with ground-water in Charlemont, MA. …

Petrology, Structural Geology, And Significance Of Mn-Andalusite From The Lower Ortega Quartzite, Tusas Mts., Nm, Usa, Nancy A. Price

Masters Theses 1911 - February 2014

The Proterozoic syn-orogenic supra-crustal package exposed in the Tusas Mountain Range in northern New Mexico includes the anomalously thick, clean, ultramature Ortega Formation quartzite (Bauer and Williams, 1989). A unique Mn-bearing horizon spans the basal contact of the quartzite and contains Mn-andalusite, quartz, hematite, rutile, zircon, monazite, phyllosilicates, and locally kyanite and gahnite in intermittent aluminous, hematite-bearing layers, on the surface of cross-beds, concentrated in high strain zones, and on cleavage planes. Large-scale Mn zoning in Mn-andalusite results from a decrease in Mn content away from localized Mn highs (XMn of up to 0.76) that commonly correspond with the location …