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Formation Conditions (formation + condition)
Selected AbstractsMineral Paragenesis and Fluid Inclusions of Some Pluton-hosted Vein-type Copper Deposits in the Coastal Cordillera, Northern ChileRESOURCE GEOLOGY, Issue 1 2003Dania Trista Abstract. Formation conditions of some vein-type copper deposits of the Tocopilla district (Deseada, San Jose, Santa Rosa) and the Gatico district (Yohanita, Toldo-Velarde, Argentina) in the Coastal Cordillera of northern Chile were inferred from mineral paragenesis and fluid inclusion data, and were compared with those of neighboring stratiform copper deposits. The vein-type copper deposits are hosted in Late Jurassic dioritic to quartz-dioritic plutons intruding extensively an andesite-dominant volcanic pile of the Jurassic La Negra Formation. Primary mineralization is characterized by chalcopyrite + magnetite + pyrite + bornite, and supergene alteration of these minerals produced anilite, covellite, atacamite and chrysocolla. The hypogene mineral assemblage indicates relatively high sulfur fugacity and weakly oxidized conditions, distinct from the stratiform copper deposits formed under low sulfur fugacity and moderately oxidized conditions. Furthermore, the fluid inclusion data of the vein-type deposits indicate high temperature (401,560d,C) and high salinity (39,68 wt% NaCl equiv.) ranges in contrast to the stratiform deposits, suggesting that this type of deposits formed by magma-associated hypersaline ore fluids. [source] Equations of state for basin geofluids: algorithm review and intercomparison for brinesGEOFLUIDS (ELECTRONIC), Issue 4 2002J. J. Adams ABSTRACT Physical properties of formation waters in sedimentary basins can vary by more than 25% for density and by one order of magnitude for viscosity. Density differences may enhance or retard flow driven by other mechanisms and can initiate buoyancy-driven flow. For a given driving force, the flow rate and injectivity depend on viscosity and permeability. Thus, variations in the density and viscosity of formation waters may have or had a significant effect on the flow pattern in a sedimentary basin, with consequences for various basin processes. Therefore, it is critical to correctly estimate water properties at formation conditions for proper representation and interpretation of present flow systems, and for numerical simulations of basin evolution, hydrocarbon migration, ore genesis, and fate of injected fluids in sedimentary basins. Algorithms published over the years to calculate water density and viscosity as a function of temperature, pressure and salinity are based on empirical fitting of laboratory-measured properties of predominantly NaCl solutions, but also field brines. A review and comparison of various algorithms are presented here, both in terms of applicability range and estimates of density and viscosity. The paucity of measured formation-water properties at in situ conditions hinders a definitive conclusion regarding the validity of any of these algorithms. However, the comparison indicates the versatility of the various algorithms in various ranges of conditions found in sedimentary basins. The applicability of these algorithms to the density of formation waters in the Alberta Basin is also examined using a high-quality database of 4854 water analyses. Consideration is also given to the percentage of cations that are heavier than Na in the waters. [source] Investigating the jet stretch in the wet spinning of PAN fiberJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Xiaomei Zeng Abstract The jet stretch of wet-spun PAN fiber and its effects on the cross-section shape and properties of fibers were investigated for the PAN-DMSO-H2O system. Evidently, the spinning parameters, such as dope temperature, bath concentration, and bath temperature, influenced the jet stretch. Also, under uniform conditions, the postdrawing ratio changed as well as that of jet stretch. When coagulation temperature was 35°C simultaneously with bath concentration of 70%, jet stretch impacted obviously the cross-section shapes of PAN fiber, but had little effect when the temperature was below 10°C or above 70°C. As the jet stretch ratio increased, the crystallinity, crystal size, sonic orientation, and mechanical properties of the as-spun fiber changed rapidly to a major value for jet stretch ratio of 0.9 where the cross section of as-spun fiber was circular. With further increasing of jet stretch ratio, the properties changed slightly but the fiber shape was not circular. The results indicated that appropriate jet stretch, under milder formation conditions in wet-spinning, could result in the higher postdrawing ratio and circular profile of PAN fiber, which were helpful to produce round PAN precursor with minor titer and perfect properties for carbon fiber. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Age and early metamorphic history of the Sanbagawa belt: Lu,Hf and P,T constraints from the Western Iratsu eclogiteJOURNAL OF METAMORPHIC GEOLOGY, Issue 5 2009S. ENDO Abstract Two distinct age estimates for eclogite-facies metamorphism in the Sanbagawa belt have been proposed: (i) c. 120,110 Ma based on a zircon SHRIMP age for the Western Iratsu unit and (ii) c. 88,89 Ma based on a garnet,omphacite Lu,Hf isochron age from the Seba and Kotsu eclogite units. Despite the contrasting estimates of formation ages, petrological studies suggest the formation conditions of the Western Iratsu unit are indistinguishable from those of the other two units,all ,20 kbar and 600,650 °C. Studies of the associated geological structures suggest the Seba and Western Iratsu units are parts of a larger semi-continuous eclogite unit. A combination of geochronological and petrological studies for the Western Iratsu eclogite offers a resolution to this discrepancy in age estimates. New Lu,Hf dating for the Western Iratsu eclogite yields an age of 115.9 ± 0.5 Ma that is compatible with the zircon SHRIMP age. However, petrological studies show that there was significant garnet growth in the Western Iratsu eclogite before eclogite facies metamorphism, and the early core growth is associated with a strong concentration of Lu. Pre-eclogite facies garnet (Grt1) includes epidote,amphibolite facies parageneses equilibrated at 550,650 °C and ,10 kbar, and this is overgrown by prograde eclogite facies garnet (Grt2). The Lu,Hf age of c. 116 Ma is strongly skewed to the isotopic composition of Grt1 and is interpreted to reflect the age of the pre-eclogite phase. The considerable time gap (c. 27 Myr) between the two Lu,Hf ages suggests they may be related to separate tectonic events or distinct phases in the evolution of the Sanbagawa subduction zone. [source] Drug substances presented as sulfonic acid salts: overview of utility, safety and regulationJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2009David P. Elder Abstract Objectives Controlling genotoxic impurities represents a significant challenge to both industry and regulators. The potential for formation of genotoxic short-chain alkyl esters of sulfonic acids during synthesis of sulfonic acid salts is a long-standing regulatory concern. This review provides a general overview of the utility of sulfonic acids as salt-forming moieties and discusses strategies for effectively minimizing the potential for alkyl sulfonate formation during the synthesis and processing of sulfonate salt active pharmaceutical ingredients. The potential implications of the recent establishment of a substantial human threshold dose for ethyl methanesulfonate for the safety assessment of alkyl sulfonates in general are also discussed. Key findings The formation of alkyl sulfonates requires highly acidic conditions, possibly combined with long reaction times and/or elevated temperatures, to generate significant amounts, and these conditions are most unlikely to be present in the synthesis of active pharmaceutical ingredient sulfonate salts. It is possible to design salt formation conditions, using a short-chain alcohol as solvent, to manufacture sulfonate salts that are essentially free of alkyl sulfonate impurities. Processes using non-acidic conditions such as ethanol recrystallization or wet granulation should not raise any concerns of alkyl sulfonate formation. Summary An understanding of the mechanism of formation of alkyl sulfonates is critical in order to avoid restricting or over-controlling sulfonic acid salts, which have many technical advantages as pharmaceutical counterions. Recent regulatory acceptance of a human threshold limit dose of 2 mg/kg per day for ethyl methanesulfonate, indicating that its toxicological risks have previously been considerably overestimated, could signal the beginning of the end over safety concerns on alkyl sulfonate residues, thus removing a major constraint from the exploitation of sulfonic acid counterions. [source] Determination of the metal ordering in meteoritic (Fe,Ni)3P crystalsJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2005O. Moretzki Synchrotron radiation diffraction studies of meteoritic (Fe,Ni)3P crystals have been performed to reveal the ordering of the elements Fe and Ni on the three metal sites M1, M2 and M3 of the unit cell. The , synthesis technique, which is a two-wavelength method using anomalous dispersion effects, was applied. For (Fe,Ni) phosphide crystals with different Fe:Ni ratios extracted from different meteorites, it was found that Ni occupies the M3 site and also partially the M2 site, avoiding the M1 position, whereas the M1 site is preferentially occupied by Fe. In connection with earlier results known from the literature, this metal distribution seems to be characteristic of this compound, and is independent of thermodynamic formation conditions. [source] Formation of TiC core-graphitic mantle grains from CO gasMETEORITICS & PLANETARY SCIENCE, Issue 5 2006Yuki KIMURA 1996). Carbonaceous materials can be formed from C2H2 and its derivatives, as well as from CO gas. In this paper, we will demonstrate that large-cage-structure carbon particles can be produced from CO gas by the Boudouard reaction. Since the sublimation temperature for such fullerenes is low, the large cages can be deposited onto previously nucleated TiC and produce TiC core-graphitic mantle spherules. New constraints for the formation conditions and the time scale for the formation of TiC core-graphitic mantle spherules are suggested by the results of this study. In particular, TiC core-graphitic mantle grains that are found in primitive meteorites that have never experienced hydration could be mantled by fullerenes or carbon nanotubes rather than by graphite. In situ observations of these grains in primitive anhydrous meteoritic matrix could confirm or refute this prediction and would demonstrate that the graphitic mantle on such grains is a metamorphic feature due to interaction of the presolar fullerenes with water within the meteorite matrix. [source] Iron oxidation state in impact glass from the K/T boundary at Beloc, Haiti, by high-resolution XANES spectroscopyMETEORITICS & PLANETARY SCIENCE, Issue 11 2005Gabriele Giuli The samples have been analyzed by Fe K-edge high-resolution X-ray absorption near edge structure (XANES) spectroscopy to obtain data on both the Fe oxidation state and the coordination number. The pre-edge peak of our high-resolution XANES spectra display noticeable variations indicative of significant changes in the Fe oxidation state spanning a wide range from about 20 to 75 mol% trivalent Fe. All data plot along the same trend, falling between two mixing lines joining a point calculated as the mean of a group of tektites studied so far (consisting of four- and five-coordinated Fe2+) to [4]Fe3+ and [5]Fe3+, respectively. Thus, the XANES spectra can be interpreted as a mixture of [4]Fe2+, [5]Fe2+, [4]Fe3+, and [5]Fe3+. There is no evidence for six-fold coordinated Fe; however, its presence in small amounts cannot be excluded from XANES data alone. Our observations can be explained by two possible scenarios: either these impact glasses formed under very reducing conditions and, because of their small size, were easily oxidized in air while still molten, or they formed under a variety of different oxygen fugacities resulting in different Fe oxidation states. In the first case, the oxidation state and coordination number would imply similar formation conditions as splash-form tektites, followed by progressive oxidation. [source] The influence of fiber formation conditions on the structure and properties of nanocomposite alginate fibers containing tricalcium phosphate or montmorillonitePOLYMER COMPOSITES, Issue 8 2010Maciej Bogu The authors devised conditions for the formation of nanocomposite calcium alginate fibers containing tricalcium phosphate (TCP) or montmorillonite (MMT). The rheological, sorptive, and strength properties of these fibers, as well as their porous and supramolecular structures were subjected to analysis. It has been concluded that the presence of nanoadditives in the material of alginate fibers decreases their susceptibility to distortion in the drawing stage. The obtained fibers are characterized by an even distribution of the nanoadditive on the fiber surface. POLYM. COMPOS., 31:1321,1331, 2010. © 2009 Society of Plastics Engineers [source] Multiple-Element Matching Reservoir Formation and Quantitative Prediction of Favorable Areas in Superimposed BasinsACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2010WANG Huaijie Abstract: Superimposed basins in West China have experienced multi-stage tectonic events and multicycle hydrocarbon reservoir formation, and complex hydrocarbon reservoirs have been discovered widely in basins of this kind. Most of the complex hydrocarbon reservoirs are characterized by relocation, scale re-construction, component variation and phase state transformation, and their distributions are very difficult to predict. Research shows that regional caprock (C), high-quality sedimentary facies (Deposits, D), paleohighs (Mountain, M) and source rock (S) are four geologic elements contributing to complex hydrocarbon reservoir formation and distribution of western superimposed basins. Longitudinal sequential combinations of the four elements control the strata of hydrocarbon reservoir formation, and planar superimpositions and combinations control the range of hydrocarbon reservoir and their simultaneous joint effects in geohistory determine the time of hydrocarbon reservoir formation. Multiple-element matching reservoir formation presents a basic mode of reservoir formation in superimposed basins, and we recommend it is expressed as T-CDMS. Based on the multiple-element matching reservoir formation mode, a comprehensive reservoir formation index (Tcdms) is developed in this paper to characterize reservoir formation conditions, and a method is presented to predict reservoir formation range and probability of occurrence in superimposed basins. Through application of new theory, methods and technology, the favorable reservoir formation range and probability of occurrence in the Ordovician target zone in Tarim Basin in four different reservoir formation periods are predicted. Results show that central Tarim, Yinmaili and Lunnan are the three most favorable regions where Ordovician oil and gas fields may have formed. The coincidence of prediction results with currently discovered hydrocarbon reservoirs reaches 97%. This reflects the effectiveness and reliability of the new theory, methods and technology. [source] The Genetic Mechanism and Model of Deep-Basin Gas Accumulation and Methods for Predicting the Favorable AreasACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2003WANG Tao Abstract, As a kind of abnormal natural gas formed with special mechanism, the deep-basin gas, accumulated in the lower parts of a basin or syncline and trapped by a tight reservoir, has such characteristics as gas-water inversion, abnormal pressure, continuous distribution and tremendous reserves. Being a geological product of the evolution of petroliferous basins by the end of the middle-late stages, the formation of a deep-basin gas accumulation must meet four conditions, i.e., continuous and sufficient gas supply, tight reservoirs in continuous distribution, good sealing caps and stable structures. The areas, where the expansion force of natural gas is smaller than the sum of the capillary force and the hydrostatic pressure within tight reservoirs, are favorable for forming deep-basin gas pools. The range delineated by the above two forces corresponds to that of the deep-basin gas trap. Within the scope of the deep-basin gas trap, the balance relationship between the amounts of ingoing and overflowing gases determines the gas-bearing area of the deep-basin gas pool. The gas volume in regions with high porosity and high permeability is worth exploring under current technical conditions and it is equivalent to the practical resources (about 10%-20% of the deep-basin gas). Based on studies of deep-basin gas formation conditions, the theory of force balance and the equation of material balance, the favorable areas and gas-containing ranges, as well as possible gas-rich regions are preliminarily predicted in the deep-basin gas pools in the Upper Paleozoic He-8 segment of the Ordos basin. [source] | |||||||||||||