نتایج جستجو برای: hydrothermal alterations
تعداد نتایج: 127690 فیلتر نتایج به سال:
Hydrothermal processes on Enceladus Saturn’s moon Enceladus has a subsurface ocean covered by a layer of ice. Some liquid escapes into space through cracks in the ice, which is the source of one of Saturn’s rings. In October 2015, the Cassini spacecraft flew directly through the plume of escaping material and sampled its chemical composition. Waite et al. found that the plume contains molecular...
One-dimensional nanostructures exhibit interesting electronic and optical properties due to their low dimensionality leading to quantum confinement effects. ZnO has received lot of attention as a nanostructured material because of unique properties rendering it suitable for various applications. Amongst the different methods of synthesis of ZnO nanostructures, the hydrothermal method is attract...
Low-temperature aqueous chemical growth methods have shown great potential in the synthesis of ZnO nanostructures. Hexamethylenetetramine (HMTA) is the most common chemical substance used in the hydrothermal synthesis. In this study zinc oxide nanoparticles were prepared via hydrothermal growth using zinc acetate dihydrate and sodium hydroxide, as precursors instead of HMTA, as it is commercial...
[1] Hydrothermal venting along the global mid‐ocean ridge system plays a major role in cycling elements and energy between the Earth’s interior and surface. We use the distribution of helium isotopes along an oceanic transect at 67°S to identify previously unobserved hydrothermal activity in the Pacific sector of the Southern Ocean. Combining the geochemical information provided by the helium i...
The Sullivan deposit of British Columbia, Canada represents an ancient submarine hydrothermal system that formed a giant Pb-Zn-Ag massive sulfide deposit. Tourmaline is abundant in the deposit and acts as a good tracer that may reveal the nature of the original hydrothermal fluids and ore-forming processes, due to its refractory characteristics. Concentrations of Zr, Hf, Nb, Ta, U and Th in tou...
Introduction: Impact events locally increase the temperature of a planetary crust, initiating hydrother-mal activity if water or ice is present. Impact-induced hydrothermal activity is responsible for mineralogical-ly and morphologically modifying many terrestrial craters [e.g., 1], and has been suggested for Martian craters [2, 3]. Present-day subsurface ice has been inferred at high latitudes...
[1] An active seafloor hydrothermal system subjects the background sediments of the Grimsey Graben (Tjörnes Fracture Zone) to alteration that produces dissolution of the primary volcaniclastic matrix and replacement/precipitation of sulfides, sulfates, oxides, oxyhydroxides, carbonates and phyllosilicates. Three types of hydrothermal alteration of the sediment are defined on the basis of the do...
introduction the shahrestanak mn deposit is located in southern qom province, 12 km southwest of the city of kahak. based on geological-structural divisions of iran, the deposit belongs to central volcanic belt or urumieh-dokhtar zone. the venarch deposit is one the most important known manganese deposits in iran. the sharestanak and venarch deposits are spatially and temporally related to each...
Knowledge of metal complexes in natural hydrothermal fluids is fundamental to our understanding of ore formation as well as other processes involving interactions between aqueous solutions and solids such as metamorphism. Our present understanding of the structure of metal complexes in natural hydrothermal fluids is incomplete due to the paucity of solubility and spectroscopic studies on geolog...
polycrystalline mfi zeolite membranes were prepared on α-alumina tubular support by hydrothermal treatments at 413 k. the synthesized zeolite membranes were characterized by xrd, sem and single gas permeation. the influence of hydrothermal treatment steps and the calcination time on the zeolite layer formation were investigated. mfi zeolite membrane prepared by four subsequent hydrothermal trea...
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