نتایج جستجو برای: sulfur geochemistry

تعداد نتایج: 38983  

2009
Robert J. Speakman Michael D. Glascock

One hundred and nineteen samples of clay (n = 42), rock and sand temper (n = 7), and pottery (n = 70) from the various drainages in and around the North Carolina Sandhills were analyzed by instrumental neutron activation analysis (NAA) at the University of Missouri Research Reactor Center (MURR). Here we report the analytical methods and describe some of the chemical patterns identified in the ...

Journal: :Environment international 2005
Alfred A Duker E J M Carranza Martin Hale

Arsenic occurs naturally in the earth's crust and is widely distributed in the environment. Natural mineralization and activities of microorganisms enhance arsenic mobilization in the environment but human intervention has exacerbated arsenic contamination. Although arsenic is useful for industrial, agricultural, medicinal and other purposes, it exerts a toxic effect in a variety of organisms, ...

2011
Ian D. Clark

1. Background 2. Elements, Nuclides, and Stable Isotopes 3. The Mass Spectrometer and Isotope Ratio Measurement 4. Isotope Fractionation 5. Temperature and Fractionation 6. Stable Isotopes in the Hydrologic Cycle 7. O in Minerals and Rocks 8. C and Carbon Cycling 9. N Cycling in Watersheds 10.S and the Sulfur Cycle 11. Chlorine and Bromine Isotopes 12. Light Lithophile Elements: δLi and δB Glos...

Journal: :Annual review of genetics 2004
Laura R Croal Jeffrey A Gralnick Davin Malasarn Dianne K Newman

Bacteria are remarkable in their metabolic diversity due to their ability to harvest energy from myriad oxidation and reduction reactions. In some cases, their metabolisms involve redox transformations of metal(loid)s, which lead to the precipitation, transformation, or dissolution of minerals. Microorganism/mineral interactions not only affect the geochemistry of modern environments, but may a...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2008
narmin bahrami adeh mitra mohtadi haghighi nahid mohammad hosseini

mixtures of mineral aggregate and modified sulfur, wherein the modified sulfur functions as a binder, are termed sulfur concretes or sulfur mortars depending on the form of the mineral aggregate. molten sulfur reacted with olefinic additive, at 130-140 ºc, and then mixed with preheated filler and aggregates. sulfur mortar samples were prepared by mixing 32 % molten sulfur, 10 % filler and 58 % ...

Journal: :Frontiers in Earth Science 2021

We present pore fluid geochemistry, including major ion and trace metal concentrations the isotopic composition of calcium sulfate, from uppermost meter sediments Gulf Aqaba (Northeast Red Sea) Iberian Margin (North Atlantic Ocean). In both locations, we observe strong correlations among calcium, magnesium, strontium, sulfate as well sulfur alkalinity, suggestive active changes in redox state p...

Journal: :Geosciences 2021

Major trace element analyses, including pyrite chemistry of pyritic mudstones shallow-marine Singa Formation Pennsylvanian–Early Permian age have been carried out to assess gold potential, the source sulfur and organic matter. Regionally, spatially correlates with Bohorok (Sumatra, Indonesia), Kaeng Krachang group (Thailand), Lebyin (Burma or Myanmar). In Southeast Asia, this formation is impor...

Farahnaz Eghbali Mohammad Reza Ehsani,

Tabas mines in Iran have coal sources which are suitable for use in metallurgy industries as coking coal. But the high sulfur content of this coal imposes severe limitations on its utilization as the sulfur oxide gases evolved from the combustion of high sulfur coals result in acid rains and corrosion of equipments. In this work, attempts have been made to reduce sulfur from high sulfur coa...

2014
M. Neveu S. J. Desch

Explosive extrusion of cold material from the interior of icy bodies, or cryovolcanism, has been observed on Enceladus and, perhaps, Europa, Triton, and Ceres. It may explain the observed evidence for a young surface on Charon (Pluto’s surface is masked by frosts). Here, we evaluate prerequisites for cryovolcanism on dwarf planet-class Kuiper belt objects (KBOs). We first review the likely spat...

2008
M. H. Farpoor H. R. Krouse

Article history: Stable isotope geochemistry Received 15 March 2008 Received in revised form 29 May 2008 Accepted 4 June 2008 Available online 30 June 2008

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