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Showing 1 to 20 of 36 for “"Barite"”.
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Geology of the Zacarias gold-silver-barite deposit, Goiás State, Brazil, The
Includes bibliographical references (pages 97-105).
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The origin of the bedded Arkansas barite deposits (with special reference to the genetic value of sedimentary features in the ore)
… mineralogic relationships existing between the barite and related sediments in the Stanley Shale in Arkansas and also to establish geometric, mineralogic, petrographic, and geochemical criteria for the interpretation of the origin of the barite and associated minerals. In addition, comparisons …
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Geology and geochemistry of the Bully Hill area of the East Shasta district, Shasta County, California.
… + weakly chalcopyrite-diseased sphalerite ± barite; (2b) deposition of coarsely-crystalline pyrite + heavily chalcopyrite-diseased sphalerite; (3a) void-filling and replacement by galena + chalcopyrite + tetrahedrite-tennantite; (3b) replacement by chalcopyrite; and (4) replacement by barite. …
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Geodynamic Evolution of the Aegean Back-arc and its Implication for Associated Precious and Base Metal Mineralization
… of galena (PbS) and ore-associated hydrothermal barite (BaSO4). New galena Pb isotope data complemented by Pb isotope data of galena from the literature exhibit a range of isotopic ratios, with a resolvable geologic pattern. Galena from deposits in the north-central Cyclades has low 206Pb/204Pb …
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Stratigraphic control and distal hydrothermal footprint of the Ursa Zn-Pb-Ag prospect, Selwyn Basin, Yukon Territory, Canada
… of the weakly altered, reduced, calcareous, and barite-bearing sedimentary units hosting the Ursa prospect. The most widespread and conspicuous hydrothermal phases include pyrite, sphalerite, and pyrite replacing earlier barite. The weakly altered rocks contain siderite and witherite. The results …
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Strength of drilling fluid filter cakes
… strength and a decrease in cake porosity as the barite volume fraction in the fluid increased. For these model fluids, the cake strength also increased as the particle size and cake porosity decreased whilst calcium carbonate cakes were stronger than the barite equivalents. Cake strength may have …
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The geochemistry of carbonate-hosted Pb-Zn-Ag mineralization in the Lavrion District, Attica, Greece: fluid inclusion, stable isotope, and rare earth element studies
… in the paragenetic sequence with fluorite and barite. Fluid inclusion studies of sphalerite, fluorite, calcite, and quartz in carbonate-replacement deposits suggest that they were deposited in thermal pulses (132°-365°C) from CO2-poor, low- to moderately-saline (1 to 20 wt% NaCl equiv) …
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Les iguanodons de Bernissart: leur évolution diagénétique et les processus de dégradation
… in the cavities during burial (pyrite, barite, sphalerite, celestine, iron oxi-hydroxides, authigenic apatite, calcium sulfate and to a lesser extent vivianite). Pyrite is the most abundant authigenic mineral in the Iguanodon fossil bones. It occurs in different morphologies (crystals, …
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Depositional and Diagenetic History of the Permian Unayzah A Reservoir, South Haradh, Saudi Arabia with Implications for Deep Gas Exploration and Development
… during the early mesogenetic stage followed by barite, quartz and carbonate cementation. Oil degradation at temperatures between 150o and 225oC produced acidic pore fluids that caused dissolution of earlier formed carbonates to generate secondary intragranular, moldic and micro pores. Thin, …
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A thermochemical study of the ore deposits of the Milliken mine, New Lead Belt, Missouri
… have been identified in the ores, including barite and Pb-aragonite, bot h of which have not previously been recognized in the district.</p> <p>Paragenetically, the ores are very complex, with four major, distinct periods of mineralization plus numerous periods of dissolution. The paragenesis …
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The Distribution of Dissolved Barium Along the U.S. Geotraces North Atlantic Transect: Impact of Biogeochemical Processes, Circulation and Phase Association
… where further enrichment of barium could enhance barite precipitation. The results demonstrated primary productivity can compensate for iron limitations during adsorption of dissolved barium to ferric oxyhydroxide through an increase in pH. There was evidence of a hydrothermal Ba input from the …
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Petrology of Mineralized and Non-Mineralized Samples from the Railroad District within the Carlin Trend, Elko, NV
… samples have stilpnomelane, Fe-richpyrite, barite, and andalusite porphyroblasts. Gold concentrations within mineralizedsamples range from 2-5 wt. % in the Chainman Formationand 2-8 wt. % in the faultbreccias. An apparent bimodal distribution of Au was found which reflects the mediadensity …
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EASTERN EQUATORIAL PACIFIC PRODUCTIVITY VIA TWO GEOCHEMICAL PROXIES
… This research examines the phosphorous and barite geochemisty of four EEP sites while also comparing the sites’ glacial and interglacial productivity variations to the geochemistry and productivity results of an independent central equatorial pacific site. Phosphorus and other elemental data …
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ΜΕΤΑΛΛΟΓΕΝΕΣΗ ΣΥΜΠΑΓΩΝ ΘΕΙΟΥΧΩΝ ΜΕΤΑΛΛΕΥΜΑΤΩΝ ΚΑΙ ΠΕΤΡΟΛΟΓΙΑ ΤΗΣ ΕΞΩΤΕΡΙΚΗΣ ΜΕΤΑΜΟΡΦΙΚΗΣ ΤΕΚΤΟΝΙΚΗΣ ΖΩΝΗΣ ΤΩΝ ΕΛΛΗΝΙΔΩΝ (Ν.Α. ΠΕΛΟΠΟΝΝΗΣΟΣ)
… ORIGIN. THE SECOND GROUP INCLUDES GALENA AND BARITE IN CARBONATE ROCKS. THE FIRST GROUP CAN BE FURTHER SUBDIVIDED INTO TWO MORPHOLOGICAL TYPES: THE FIRST INCLUDES DISSEMINATED CU WITH MINOR FE SULFIDE ASSEMBLAGES IN PORPHYRITIC VOLCANIC ROCKS, WHEREAS THE SECONDTYPE INCLUDES PB-ZN-FE- CU …
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Gold-silver mineralization at the London-Virginia Mine, Buckingham County, Virginia
… in hydrothermal silica, goethite, amounts of barite, gold. The deposit limonite, and pyrite with minor calcite, base metal sulfides and is believed to have formed as a result of exhalative processes analogous to those currently active in the Atlantis II Deep of the Red Sea. Silica-rich, …
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Experimental and Analytical Investigation of Particle Dynamics in Newtonian and non-Newtonian Fluids in a Taylor-Couette Cell
… of clay and other heavy particles like barite with a density of 4.2 g/cm<sup>3</sup>, often exhibit higher yield stresses and distinct shear-thinning profiles compared to the model fluids used. This work investigated the settling of five different materials, including alumina (density of …
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Barium isotope cycling in the marine environment: Pathways of fractionation and implications for paleoceanographic applications
… particulate phase of marine barium, the mineral barite (BaSO₄) through its inception in the water column, during deposition, and ultimately into the rock record. To that end, I characterize the depth, spatial region, and general controls on particulate Ba formation in the South Pacific Ocean …
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Barium isotope cycling in the marine environment: pathways of fractionation and implications for paleoceanographic applications
… particulate phase of marine barium, the mineral barite (BaSO4) through its inception in the water column, during deposition, and ultimately into the rock record. To that end, I characterize the depth, spatial region, and general controls on particulate Ba formation in the South Pacific Ocean …
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Pattern formation in geochemical systems.
… bifurcation is observed. Oscillatory zoning in barite-celestite system is simulated to quantitatively describe the results of the previously reported nucleation and growth experiments. The zoning is thought to be formed by autocatalytic growth from an aqueous solution. In addition to the …
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Ultrasound propagation in colloidal dispersions
… obtain agreement. Attenuation as a function of barite concentration in Newtonian liquids was investigated and the ultrasonic particle radius was found to be systematically larger than expected. This is attributed to particle rugosity. Measurements of a[alpha] and c using non-gelling aqueous …
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