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Showing 1 to 20 of 75 for “"anhydrite"”.
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The stability of gypsum and anhydrite in the geologic environment
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Geology, 1954.
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Numerical Modeling of the Hydrothermal System at East Pacific Rise (EPR) 9 Degrees 50' N Including Anhydrite Precipitation
… uncertain. To better understand the effects of anhydrite precipitation on hydrothermal flow paths, we conduct 2-D numerical simulations of hydrothermal circulation at a mid-ocean ridge using a NaCl-H2O numerical code. The simulations focus on East Pacific Rise hydrothermal system at 950N due to …
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THORIUM SPECIATION IN SYNTHETIC ANHYDRITE, PLACER ILMENITE CONCENTRATE, AND TITANIA SLAG: IMPLICATIONS FOR THORIUM GEOCHEMICAL BEHAVIOR, SEQUESTRATION, AND BENEFICIATION
… were simulated to synthesize thorium-bearing anhydrite. Synchrotron ThLIII-edge X-ray absorption spectroscopy (XAS) reveals that lattice-bound Th in anhydrite, via the substitution Th4++1O2–iCa2+-1 with an interstitial O2– ion, can account for at least 1780 ppm Th in anhydrite produced in …
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A mechanical well log study of the popular interval of the Mississippian Madison Formation in North Dakota
… for petroleum production. Limestone, dolomite, anhydrite and salt were differentiated using mechanical well logs.</p> <p>The complex facies of the Madison are subdivided into para-time rock units (the Poplar interval is one) on the basis of extensive thin anhydrite beds which are considered …
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The petroleum geology of the Midale subinterval in north central North Dakota
… logs and core samples from 10 wells.</p> <p>The anhydrite and dolomite units of the Rival subinterval, which underlie the Midale, and the Ratcliffe interval, which over lies the Midale, reflect the restricted conditions characteristic of a penesaline stage in a major evaporite cycle. The …
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Petrography of the Midale subinterval in the Bottineau and Renville counties area, North Dakota
… and oolitic limestones, and primary anhydrite. Dolomitization of the limestones in varying stages is common and the dolomitized limestones are usually fine grained. Course crystals of secondary anhydrite are common as vug and fracture filling and as a replacement of the …
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Depositional Facies and Petrophysical Characterization of the Leonardian Carbonate (Lower Clear Fork), Tex-Mex, S.E. Field, Central Basin Platform, West Texas
… a mixed succession of dolomite interbedded with anhydrite, minor clay minerals, and siliciclastics. The high heterolithic nature of the reservoir makes efficient recovery of hydrocarbons difficult. This situation requires an understanding of the variability in depositional facies in terms of …
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IDENTIFYING SALT SUTURE ZONES AND LITHOLOGICAL CHANGES OF THE LOUANN SALT IN THE GULF OF MEXICO BASIN, LA. U.S.A.
… salt primarily consists of halite, with minor anhydrite, gypsum, and sylvite, indicating continuous precipitation. Geochemical analysis identifies localized anhydrite zones, suggesting fluctuating brine chemistry, while quartz and clay minerals point to siliciclastic influx. The study reveals …
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Evaluating the Potential of Scaling due to Calcium Compounds in Hydrometallurgical Processes
… of CaSO4 hydrates (gypsum, hemihydrate and anhydrite) depend on solution conditions, i.e., temperature, pH and concentration of ions present. The transformation between CaSO4 hydrates is one of the common causes of scale formation. A systematic study was carried out to investigate the effect …
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Petroleum potential of the Tilston interval (Mississippian) of central North Dakota
… (subtidal, shoal, tidal flat and supratidal anhydrite), and two geographically restricted facies (lagoonal and elastic) and represents a regressive sequence. </p><p> Tilston deposition began with the subtidal facies, deposited on a broad, shallow shelf. As the sea regressed this was followed …
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Petrographic, geochemical, and textural analyses of interbedded gypsum and Cu-ore deposits in the Upper Miocene Boleo Formation, Baja California Sur, México
… and secondary gypsum, together with residual anhydrite, provides evidence for burial followed by uplift, while the position of stylolites within the core indicates shallow burial depths. During uplift, meteoric fluids infiltrated fractures, resulting in clay alteration, precipitation of oxide …
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Diagenetic controls of reservoir quality in the Mississippian Wayne Beds in the Williston Basin, Bottineau County, North Dakota
… origin. Permeability reduction by pore-bridging anhydrite cements post-date the pore-occluding dolomites. Wayne beds contain much less pore-bridging anhydrite beneath paleohighs where the overlying Glenburn evaporites were removed due to erosion than beneath paleolows where the Glenburn is still …
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Basalt alteration and its consequences
… sulfur cycle; specifically with respect to anhydrite, which precipitates directly from seawater upon heating. I explore how past variations in ocean chemistry may have affected both the amount and the depth of anhydrite precipitation and speculate on the ultimate fate of this precipitated …
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Depositional environments and diagenesis of the Ratcliffe interval, Madison group (Mississippian), Williston Basin, North Dakota
… mudstone, 5) quartz siltstone packstone, and 6) anhydrite-dolomite mudstone. These facies were deposited in a regressive setting.</p> <p>The initial deposition consisted mainly of marine limestones. The environment gradually became more restricted and deposition of large amounts of anhydrite and …
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A Parameterized Approach to Partitioning Between Focused and Diffuse Heat Output and Modeling Hydrothermal Recharge at The East Pacific Rise 9°50´N
… microseismicity in the oceanic crust I find that anhydrite precipitation is likely to result in rapid sealing of pore space in the recharge zone. This would lead to rapid decay of hydrothermal venting, which is contrary to observations. Then I consider two-dimensional numerical models of …
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Carbon and sulfur isotopic constraints on Ediacaran biogeochemical processes, Huqf supergroups, Sultanate of Oman
… forms (carbonate-associated sulfate: CAS, and anhydrite), providing an opportunity to investigate isotopic offsets reported between these seawater sulfate proxies. The results indicate that changing basin restriction can significantly alter the isotopic composition of gypsum/anhydrite and …
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Depositional environments, ichnology and diagenesis of the upper Frobisher-Alida beds of the Elkhorn Ranch and Roughrider fields of western North Dakota
… packstone-wackestone; 6) nodular and bedded anhydrite (LT-6). Lithofacies generally follow a depositional sequence of thick units of sublittoral carbonates, followed by a thin sequence of littoral carbonates, and culminating in a thick unit of sublittoral evaporites. Sublittoral rocks …
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Geochemical tracers of processes affecting the formation of seafloor hydrothermal fluids and deposits in the Manus back-arc basin
… volatile input in back-arc hydrothermal systems. Anhydrite in deposits record the same range of REE patterns, suggesting that REE distributions preserved in anhydrite can be used as indicators of past magmatic acid volatile input. Vent fluid heavy metal and metalloid concentrations also exhibit …
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Microfacies analysis of the lower paleocene beda formation in Western Concession 59 and Block 59F, Sirte Basin, Libya /
… wackestones, and packstones with dolomites and anhydrite. Rock textures, faunal assemblages and sedimentary structures suggest shallow, clear, warm waters and low to moderate energy conditions within the depositional shelf environment. The Beda Formation represents a shallowing-upward sequence …
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