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Full-Text Articles in Physical Sciences and Mathematics

Shallow Slab Fluid Release Across And Along The Mariana Arc-Basin System: Insights From Geochemistry Of Serpentinized Peridotites From The Mariana Fore Arc, Ivan P. Savov, Jeffrey G. Ryan, Massimo D'Antonio, Patricia Fryer Sep 2007

Shallow Slab Fluid Release Across And Along The Mariana Arc-Basin System: Insights From Geochemistry Of Serpentinized Peridotites From The Mariana Fore Arc, Ivan P. Savov, Jeffrey G. Ryan, Massimo D'Antonio, Patricia Fryer

Geology Faculty Publications

Shallow slab devolatilization is not only witnessed through fluid expulsion at accretionary prisms, but is also evidenced by active serpentinite seamounts in the shallow fore-arc region of the Mariana convergent margin. Ocean Drilling Program (ODP) Leg 195 recovered serpentinized peridotites that present a unique opportunity to study the products of shallow level exchanges between the upper mantle and slab-derived fluids. Similar to samples recovered during ODP Leg 125, the protoliths of these fore-arc serpentinized peridotites are mantle harzburgites that have suffered large volume melt extraction (up to 25%) prior to interactions with fluids released from the downgoing Pacific Plate. Samples …


Outcrop Analog For Lower Paleozoic Hydrothermal Dolomite Reservoirs, Mohawk Valley, Ny, Brian E. Slater Jan 2007

Outcrop Analog For Lower Paleozoic Hydrothermal Dolomite Reservoirs, Mohawk Valley, Ny, Brian E. Slater

Geology Theses and Dissertations

Geochemical analysis and field relations of linear dolomite bodies occurring in outcrop in the Mohawk Valley of New York suggest that they have undergone significant fault-related hydrothermal alteration. The dolomite occurs in the Lower Ordovician Tribes Hill Formation, which is regionally an early Ordovician shaley limestone with patchy dolomitization. The outcrop has an en echelon fault, fracture, and fold pattern. A 3D ground penetrating radar survey of the quarry floor has helped to map out faults, fractures, anticlines, synclines and the extent of dolomitization. Most of the dolomitization occurs in fault-bounded synclines or “sags” flanked by anticlines. The dolomite structures …


The Impact Of Host Rock Geochemistry On Bacterial Community Structure In Oligotrophic Cave Environments, Hazel A. Barton, Nicholas M. Taylor, Michael P. Kreate, Austin C. Springer, Stuart A. Oehrle, Janet L. Bertog Jan 2007

The Impact Of Host Rock Geochemistry On Bacterial Community Structure In Oligotrophic Cave Environments, Hazel A. Barton, Nicholas M. Taylor, Michael P. Kreate, Austin C. Springer, Stuart A. Oehrle, Janet L. Bertog

International Journal of Speleology

Despite extremely starved conditions, caves contain surprisingly diverse microbial communities. Our research is geared toward understanding what ecosystems drivers are responsible for this high diversity. To asses the effect of rock fabric and mineralogy, we carried out a comparative geomicrobiology study within Carlsbad Cavern, New Mexico, USA. Samples were collected from two different geologic locations within the cave: WF1 in the Massive Member of the Capitan Formation and sF88 in the calcareous siltstones of the Yates Formation. We examined the organic content at each location using liquid chromatography mass spectroscopy and analyzed microbial community structure using molecular phylogenetic analyses. In …


Stream Sediment Geochemical Exploration For Gold In The Kazdağ Dome In The Biga Peninsula, Western Turkey, Hüseyi̇n Yilmaz Jan 2007

Stream Sediment Geochemical Exploration For Gold In The Kazdağ Dome In The Biga Peninsula, Western Turkey, Hüseyi̇n Yilmaz

Turkish Journal of Earth Sciences

The Tuztaşı Au-Ag mineralized system was discovered within the Kazdağ dome using BLEG (bulk leach extractable gold) and 180-µm stream sediment geochemical data collected across the Biga Peninsula in western Turkey. The deposit is located within the hinge of an antiform consisting mainly of high-grade metamorphic and mélange rocks that include the Altınoluk Pb-Zn-Cu-Ag-Au and Evciler Fe-Au-Cu deposits on the southern and on the northern flanks, respectively; no mineralization has been reported prior to this work which was first carried out in 1996 between Altınoluk and Evciler. The BLEG Ag/Au ratios at Tuztaşı (max 87) and Altınoluk (max 43) are …


The Dikili-Çandarlı Volcanics, Western Turkey: Magmatic Interactions As Recorded By Petrographic And Geochemical Features, Zeki̇ye Karacik, Yücel Yilmaz, Julian A. Pearce Jan 2007

The Dikili-Çandarlı Volcanics, Western Turkey: Magmatic Interactions As Recorded By Petrographic And Geochemical Features, Zeki̇ye Karacik, Yücel Yilmaz, Julian A. Pearce

Turkish Journal of Earth Sciences

Located in the northwestern part of the Aegean region, Dikili-Çandarlı volcanic suite contains products representative for the western Anatolian Miocene volcanism. They can be divided into two main groups: the Dikili and the Çandarlı groups. The Dikili group is Early-Middle Miocene in age and consists mainly of pyroclastic rocks, andesitic-dacitic lavas, lava breccia, lahar flows and associated sedimentary rocks. The lavas contain disequilibrium phenocrysts assemblages. The Çandarlı group consists of Upper Miocene-Pliocene lava and sediment associations. The volcanic rocks consist mainly of rhyolitic domes and basaltic trachyandesite-basaltic andesite lavas erupted along the NW-SE- and NE-SW-trending fault systems; the faults controlled …


Jurassic Volcanism In The Eastern Pontides: Is It Rift Related Or Subduction Related?, Cüneyt Şen Jan 2007

Jurassic Volcanism In The Eastern Pontides: Is It Rift Related Or Subduction Related?, Cüneyt Şen

Turkish Journal of Earth Sciences

The Jurassic volcanic rocks in the centre of the northern zone (south of Trabzon City) provide important constraints on the evolution of Pontides. The investigated volcanic rocks form a transitional series between tholeiitic and calc-alkaline, and is dominated by basalt, basaltic andesite and andesite. Geochemically, they are enriched in LILE and LREE contents and depleted in HFSE [(La/Yb)_N= 2.2 - 8.5; (Nb/La)_N= 0.1 - 0.77)] compared to mid-ocean ridge basalts and have radiogenic Nd isotope ratios of \epsilonNd(210 Ma)= -0.72 to 3.24. These trace element and isotope data suggest that these rocks were derived from low degrees of partial melting …


Aquifer-Scale Controls On The Distribution Of Nitrate And Ammonium In Ground Water Near La Pine, Oregon, Usa, Stephen R. Hinkle, J. K. Böhlke, John H. Duff, David S. Morgan, Rodney J. Weick Jan 2007

Aquifer-Scale Controls On The Distribution Of Nitrate And Ammonium In Ground Water Near La Pine, Oregon, Usa, Stephen R. Hinkle, J. K. Böhlke, John H. Duff, David S. Morgan, Rodney J. Weick

United States Geological Survey: Staff Publications

Geochemical and isotopic tools were applied at aquifer, transect, and subtransect scales to provide a framework for understanding sources, transport, and fate of dissolved inorganic N in a sandy aquifer near La Pine, Oregon. NO3 is a common contaminant in shallow ground water in this area, whereas high concentrations of NH4– N (up to 39 mg/L) are present in deep ground water. N concentrations, N/Cl ratios, tracer- based apparent ground-water ages, N isotope data, and hydraulic gradients indicate that septic tank effluent is the primary source of NO3. N isotope data, N/Cl and N/C relations, …


Fluid Flow In The Central North Slope Foreland Basin, Alaska, Anna Marie Bélanger Jan 2007

Fluid Flow In The Central North Slope Foreland Basin, Alaska, Anna Marie Bélanger

LSU Master's Theses

Previous studies of the areal variations in heat flow and spatial variations in formation water salinity and hydraulic head are consistent with the existence of a currently active, topographically-driven regional fluid flow regime in the National Petroleum Reserve Alaska (NPRA) portion of the western North Slope foreland basin. This conclusion is also supported by the results of numerical modeling of fluid flow and heat transport in the area. This work has now been extended to the east. The results of this study demonstrate that the Permian though Cenozoic age sediments of the central North Slope foreland basin have been significantly …