نتایج جستجو برای: pyrite
تعداد نتایج: 3387 فیلتر نتایج به سال:
Acid mine drainage (AMD) from abandoned coal mines continues to be one of the most significant environmental problems. Remediation of AMD requires an addition of lime source to decrease the acidity, and grouting the entire mine and encapsulating the pyrite by calcium-rich additives is often employed. Utilization of alkaline coal combustion by-products (CCBs) has gained acceptance in such remedi...
Citation Sun, Ruoshi et al. " Intrinsic stoichiometry and oxygen-induced p-type conductivity of pyrite FeS_{2}. " Physical Review B 84 Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. ...
Black shales in the geologic record have long been considered to reflect deposition under anoxic or even euxinic conditions. Although bottom-water anoxia favors deposition of black shales, certain biological indicators, such as benthic fossils and bioturbation, suggest that bottom-water conditions may not have been as persistently anoxic as commonly presumed. Examination of twelve marine carbon...
introduction pyrite is the most abundant sulfide mineral in low sulfidation ore deposits. experimental studies have shown that low-temperature ( 200°c) from hydrothermal or metamorphic fluids (butler and rickard, 2000). framboidal pyrite mostly occurs in sedimentary environments, though it could also form during metamorphism and hydrothermal alteration (scott et al., 2009). the pyrite formed te...
We assembled a microfluidic device that enables highresolution structural studies of nucleic acids. The device contains a mineral matrix capable of rapidly generating hydroxyl radicals to cleave the solvent accessible backbone of nucleic acids. Protection from radical cleavage (footprinting) can identify protein binding sites or the presence of tertiary structure. Here we report the fabrication...
Ambient pyrites of two distinct types were described from middle Precambrian rocks of the Lake Superior area. A new class of this phenomenon is here described from middle Precambrian chert from western Australia. The newly found ambient pyrites are quite minute and characteristically occur in groups forming a "starburst" pattern. All three types of ambient pyrite may be explained in terms of pr...
The supercritical water-pyrite interface has been studied by ab initio molecular dynamics simulation. Extreme conditions are relevant in the iron-sulfur world (ISW) theory where prebiotic chemical reactions are postulated to occur at the mineral-water interface. We have investigated the properties of this interface under such conditions. We have come to the conclusion that hot-pressurized water...
Almost three centuries have passed since Henckel’s monumental work on pyrite (Henckel, 1725, 1757). The new book by David Rickard, world authority on sulfide chemistry, geochemistry, geomicrobiology, biogeochemistry and ore geology, is a most welcome state-of-the-art report about this humble but fascinating mineral. As stated in the preface, the book targets a popular rather than an academic au...
The mineralogy of S-bearing phases, S-contents, and S-isotopic compositions of sediments and interstitial waters were determined for three cores drilled during Leg 129 in the western Pacific. Pelagic clays, chalks, and radiolarites generally contain 350-1200 ppm S, with essentially all S present as sulfate. Volcanogenic turbidite units contain about 400 ppm S, with about 10%-20% of total sulfur...
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