23 research outputs found

    Genetic relationship between silver-lead-zinc mineralization in the Wutong deposit, Guangxi Province and Mesozoic granitic magmatism in the Nanling belt, southeast China

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    More than 50% of the world's total reserves of tungsten are in China and most tungsten deposits are located in the Nanling range in southeast China. This study explores the potential genetic relationship between tungsten-tin (W-Sn) mineralization and shallower Ag-Pb-Zn deposits in the Nanling range based on data from the Wutong deposit, Guangxi Province. The lead, oxygen, carbon, sulfur, and strontium isotopic compositions of minerals at Wutong indicate that a single crustal-derived fluid was responsible for mineralization. Wutong likely formed at relatively low temperatures (∌200-300°C) and low pressures, as indicated by the similarity between homogenization temperatures of fluid inclusions and those estimated from S isotopic compositions of minerals. The hĂŒbnerite age (92.3-104.4Ma) indicates that the Wutong mineralization is likely related to nearby Late Yanshanian (Cretaceous) S-type granites derived from Proterozoic crust. This mineralization event coincides with the last W-Sn mineralization event and the Cretaceous peak of mineralization in the Nanling range

    Fluid inclusion evidence for impact-related hydrothermal fluid and hydrocarbon migration in Creataceous sediments of the ICDP-Chicxulub drill core Yax-1

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    Fluid inclusions studies in quartz and calcite in samples from the ICDP-Chicxulub drill core Yaxcopoil-1 (Yax-1) have revealed compelling evidence for impact-induced hydrothermal alteration. Fluid circulation through the melt breccia and the underlying sedimentary rocks was not homogeneous in time and space. The formation of euhedral quartz crystals in vugs hosted by Cretaceous limestones is related to the migration of hot (>200 degrees C), highly saline, metal-rich, hydrocarbon-bearing brines. Hydrocarbons present in some inclusions in quartz are assumed to derive from cracking of pre-impact organic matter. The center of the crater is assumed to be the source of the hot quartz-forming brines. Fluid inclusions in abundant newly-formed calcite indicate lower cyrstallization temperatures (75100 degrees C). Calcite crystallization is likely related to a later stage of hydrothermal alteration. Calcite precipitated from saline fluids, most probably from formation water. Carbon and oxygen isotope compositions and REE distributions in calcites and carbonate host rocks suggest that the calcite-forming fluids have achieved close equilibrium conditions with the Cretaceous limestones. The precipitation of calcite may be related to the convection of local pore fluids, possibly triggered by impact-induced conductive heating of the sediments.The Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

    Anti-A and anti-B titers in platelets for transfusion across ABO : evaluation of a routine analyze and implementation of a screening method

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    Trombocyter Àr suspenderade i plasma som innehÄller antikroppar mot de blodgruppsantigen som saknas pÄ erytrocyterna. För att minimera risken för en hemolytisk reaktion bestÀms titern av anti-A och anti-B. Gelkortsteknik anvÀnds för att detektera antikropp-antigensreaktioner och baseras pÄ agglutinationer i en gel. Syftet med studien var att undersöka titern av anti-A och anti-B i trombocytenheter, samt att utvÀrdera en rutinanalys och utveckla en screeningmetod. I studien analyserades enheter av blodgrupp O och A. De kontrollerades mot anti-A och/eller anti-B bÄde för IgG och IgM antikroppar. En screeningmetod utvecklades för att kunna screena O-enheterna och en grÀns pÄ 1:100 respektive 1:250 undersöktes. Resultatet kunde pÄvisa en stor skillnad i titer mellan O-och A-enheter. Titern skiljer sig signifikant beroende pÄ om titern bestÀms i plasma eller frÄn den fÀrdiga (utspÀdda) enheten. En screeningmetod pÄ 1:100 pÄvisade att 86 % av enheterna hade bedömts som hög titer och en screeningmetod pÄ 1:250 visade att andelen sjönk till 31 %. Geltekniken Àr en kÀnslig metod och Àr beroende av kompetent personal vid avlÀsning. En del studier visar liknande resultat men andelen enheter med hög titer varierar och likasÄ metoder och titergrÀns. Detta pÄvisar svÄrigheterna i att bestÀmma en kritisk titer och att förutse risker hos patienten. Andra faktorer tros ocksÄ kunna pÄverka riskerna. Införande av en screeningmetod pÄ 1:250 kan öka antalet enheter som kan transfunderas över ABO-barriÀren.Platelets are suspended in plasma containing antibodies to the blood group antigen missing on the erythrocytes. To minimize the risk of hemolytic reaction, the titrers of anti-A and anti-B are determined. The gel test is used to detect antibody-and antigen responses and is based on agglutinations in gel. The purpose was to investigate the titers of anti-A and/or anti-B in platelets. A routine analysis was evaluated and a screening method was implemented. In the study, units of blood group O and A were analyzed. They were checked against anti-A and anti-B for both IgG and IgM antibodies. A screening method was developed to screen the O-units and a limit of 1:100 and 1:250 was used. The results showed great difference in titers between O and A units. The titers differ significantly depending on whether the titers are determined in plasma or from the finished (diluted) unit. A screening method at 1:100 showed that 86 % of the units was rated as high titer while a screening method of 1:250 showed that this was reduced to 31 %. Gel technology is a sensitive method and is dependent on competent staff when reading the agglutinations. Some studies show similar results, but the proportion of high titer units, methods and critical titers varies. It proves the difficulty in determining a critical titer and predicting risks for the patient. Other factors are also believed to influence the risks. Implementation of a 1:250 screening method is believed to increase the number of units that can be transfused over the ABO barrier

    Genetic relationship between silver-lead-zinc mineralization in the Wutong deposit, Guangxi Province and Mesozoic granitic magmatism in the Nanling belt, southeast China

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    More than 50 % of the world's total reserves of tungsten are in China and most tungsten deposits are located in the Nanling range in southeast China. This study explores the potential genetic relationship between tungsten–tin (W–Sn) mineralization and shallower Ag–Pb–Zn deposits in the Nanling range based on data from the Wutong deposit, Guangxi Province. The lead, oxygen, carbon, sulfur, and strontium isotopic compositions of minerals at Wutong indicate that a single crustal-derived fluid was responsible for mineralization. Wutong likely formed at relatively low temperatures (∌200–300 °C) and low pressures, as indicated by the similarity between homogenization temperatures of fluid inclusions and those estimated from S isotopic compositions of minerals. The hĂŒbnerite age (92.3–104.4 Ma) indicates that the Wutong mineralization is likely related to nearby Late Yanshanian (Cretaceous) S-type granites derived from Proterozoic crust. This mineralization event coincides with the last W–Sn mineralization event and the Cretaceous peak of mineralization in the Nanling range.ISSN:0026-4598ISSN:1432-186
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