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Showing 1 to 20 of 39 for “"silicification"”.
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The Experimental Silicification of Bacillus subtilis
… dissolved Fe, and dissolved Al upon silicification processes. Results from initial experiments demonstrated that Bacillus subtilis a common soil bacterium, persists in better condition in the presence of Fe and that silica interacts with cellular surfaces in the presence and absence …
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The Experimental Silicification of Bacillus subtilis
… dissolved Fe, and dissolved Al upon silicification processes. Results from initial experiments demonstrated that Bacillus subtilis a common soil bacterium, persists in better condition in the presence of Fe and that silica interacts with cellular surfaces in the presence and absence …
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Exploring the silicification of microbes and understanding their role in the fossil record
… peritidal environments were fossilized by silicification, but the environmental and biological factors that shaped these structures and enabled this type of preservation are not well understood. Recent work has shown that coccoidal cyanobacteria can become fossilized because they can …
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Silicification across the Betze-Post Carlin-type gold deposit: Clues to ore fluid properties and sources, Northern Carlin Trend, Nevada
Ore fluid properties and sources at the Betze-Post deposit, the largest Carlin-type gold system in the world (∼49 million ounces Au), are not well understood. To improve knowledge of ore fluids, the geochemical, textural, and fluid inclusion characteristics of ore, late-ore, and post-ore quartz …
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Paragenesis of Lacustrine Microbialites in the Upper Wilkins Peak Member, Green River Formation, Wyoming
… with diagenetic dolomite and abundant secondary silicification. Later, dolomite replaces both calcite and quartz. Pores are commonly filled with 20 μm euhedral dolomite cements and in some samples with 10 μm crystals of quartz replacing dolomite. The diagenetic sequence for microbialites below …
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Argillic Alteration Associated With the Amethyst Vein System, Creede Mining District, Colorado (Illite, Smectite)
… the Creede mining district, southwest Colorado. Silicification and argillization are the two dominant facies of hydrothermal alteration associated with the deposit. Most silicification occurs in the intermediate and deep levels of the system and most argillized rock occurs high in the system.
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SILICON ISOTOPE AND PETROGRAPHIC INVESTIGATIONS OF SILICIFIED CARBONATE ROCKS: IMPLICATIONS FOR IMPROVED PARAGENETIC SEQUENCING AND PROXIES FOR PALEOZOIC OCEAN CHEMISTRY
… confirming petrographic evidences of early silicification of the voids compared to microquartz comprising the septal walls. Application of the isotopic data from silicified coral fossils were used to estimate pre-diatom ocean water silicon isotopic compositions, and indicate the need for …
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Paragenesis, fluid origin, and thermal history of a low-sulfidation epithermal gold-silver system
… with pyrite, found in zones of intense silicification, and precipitated due to sulfidation of rhyolitic host rock during the earliest stages of hydrothermal activity. The remaining gold occurs freely in breccia matrix quartz and was deposited after silicification as a result of cooling …
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Determining the physico-chemical conditions on the early earth : Barberton scientific drilling project, South Africa
… characterized. In addition, alteration and silicification associated with distinct emerald green, fuchsite-(Crmica)- carbonate-quartz alteration zones is commonly found beneath chert horizons in the mafic-ultramafic rocks of the Onverwacht Group of the BGB. The origin of this silicification …
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Biologically Inspired Design of Protein-Silica Hybrid Nanoparticles for Drug Delivery Applications
… system along three avenues: 1) proof-of-concept silicification (i.e. the formation and deposition of silica upon organic materials) of ELP micellar templates, 2) encapsulation and pH-triggered release of small, hydrophobic chemotherapeutics, and 3) selective silicification of templates to …
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Recognising cryptic alteration surrounding the Mount Isa Copper Deposits: Implications for controls on fluid flow, and mineral exploration
… The silica-dolomite is characterised by silicification and brecciation of shales, recrystallisation of dolomite, and intense ¹⁸O-depletion, from δ¹⁸O ≈ 22‰ VSMOW in the least altered rocks to δ¹⁸O ≈ 10‰ in the most altered zone. These zones are spatially associated with structural …
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The Ecological Drivers and Consequences of Grass Silicon Accumulation
… the primary drivers of variation in plant silicification, focusing specifically on variation in grassland ecosystems. I developed novel methods to quantify plant silicon (Appendix F), which I then applied to studies at the individual, landscape, and global scale. At the individual plant …
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Depositional environments and diagenesis of the Mississippian Bottineau interval (Lodgepole) in North Dakota
… included stylolitization, solution, fracturing, silicification, hematite replacement, dolomitization, and anhydritization. Stylolitization and fracturing began after complete lithification, as did silicification which produced chert nodules in the restricted shelf facies. This was followed by …
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A Comparative Study of Silicified Rock Reservoir in Shunnan 4 well of Tarim Basin with Hydrothermal Chert Reservoir of Parkland Gas Field in Western Canada Sedimentary Basin
… The most important diagenetic features to the silicification are identified including replacement quartz, quartz cement (characterized by 4 textures: equant quartz, bladed quartz, overgrowth and quartz cement in later fractures) and three types of calcite cement (CC1-CC3). Geochemical analysis …
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Petrology and geochemistry of the Killdeer carbonates
… limestone, (2) dolomitization of limestone, (3) silicification of carbonates and tuffites, and (4) minor silicification, deposition of secondary calcite, formation of zeolites.</p> <p>The essential ions for the formation of the carbonate rocks were transported to the depositional basin by an …
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Geochemical fingerprinting of carbonate wall rock alteration at major base metal sulphide deposits in the Otavi Mountain Land, Namibia
… recrystallisation, calcitisation and carbonate silicification. Optical cathodoluminescence imaging, electron probe micro analysis, X-ray fluorescence spectrometry, X-ray diffraction, high performance ion chromatography, proton probe micro analysis, stable isotope techniques, and fluid inclusion …
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Integrated approach to solving reservoir problems and evaluations using sequence stratigraphy, geological structures and diagenesis in Orange Basin, South Africa
… cementation/micritization, dissolution, silicification/overgrowth of quartz, and fracturing. The Eh-pH shows that the cements in the area of the basin under investigation were precipitated under weak acidic and slightly alkaline conditions. The δ18O isotope values range from -1.648 to …
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