热液中二氧化硅与成矿元素锡络合作用的实验标定   总被引：2，自引：0，他引：2  

樊文苓  陈紫新  王声远  田弋夫 《矿物岩石地球化学通报》1997,(3)

热液中二氧化硅与成矿元素锡络合作用的实验标定＊樊文苓陈紫新王声远田弋夫（中国科学院矿床地球化学开放研究实验室，贵阳５５０００２）关键词锡石溶解度二氧化硅的络合作用迁移形式前人对锡在流体中迁移形式的实验研究和热力学计算表明，锡（Ⅱ）的多种氯络合物是高温...  相似文献   

四川呷村黑矿型矿床硅质岩的硅、氧同位素组成及其与现代海底硅质烟囱比较研究   总被引：14，自引：0，他引：14  

侯增谦  吴世迎  T.Urabe 《地质论评》1996,42(6)

本文首次报道了川西呷村黑矿型矿床硅质岩的硅、氧同位素组成,其δ~(18)O为12.8‰-18.3‰纵,形成温度约99-120℃,δ~(30)Si为0.0‰-1.5‰,与Mariana和GalaPagos热液硅质烟囱的δ~(30)Si值范围基本相当,揭示两者具相似的形成机制。硅质岩和硅质烟囱δ~(30)Si最大值与相伴火山岩δ~(30)Si值一致,反映硅质来自被热液淋滤交代的火山岩系。根据SiO_2溶解度-温度关系提出,来自海底之下1-2km处的水-岩反应带、温度高于320℃的初始流体,通过绝热上升或传导冷  相似文献   

Silica depleted melting of pelites. Petrogenetic grid and application to the Susqueda Aureole, Spain   总被引：2，自引：0，他引：2  

M. Riesco  K. Stüwe  J. Reche  F. J. Martinez 《Journal of Metamorphic Geology》2004,22(5):475-494

Metapelitic rocks in the low pressure contact metamorphic aureole around the Susqueda igneous complex, Spain show a number of features that make them an ideal testing ground for the modelling of silica‐undersaturated melting. Rocks in the aureole experienced localized depletion in silica by the segregation of quartz veins during a pre‐anatectic, regional cordierite‐andalusite grade metamorphic event. These rocks were then intruded by gabbroic to dioritic rocks of the Susqueda igneous complex that formed a migmatitic contact metamorphic aureole in the country rocks. This migmatisation event caused quartz‐saturated hornfels and restite formation in rocks that had experienced no quartz vein segregation in the previous regional metamorphic event, but silica‐undersaturated melting in those rocks that were previously depleted in silica. Silica‐undersaturated melting is investigated using a new petrogenetic P–T projection and equilibrium pseudosections calculated in the KFMASH and NCKFMASH systems, respectively. The grid considers quartz absent equilibria and a range of phases that form typically in silica‐undersaturated bulk compositions, for example corundum. It is shown that the quartz‐rich precursors in the Susqueda contact aureole produced about 10% melt during contact metamorphism. However, most of this melt was extracted leaving behind rocks with restitic bulk compositions and minor leucosome segregation. It is suggested that the melt mixed with the host igneous rocks causing an apparent magmatic zoning from diorite in the centre of the complex to tonalite at the margins. In contrast, the quartz‐poor precursors (from which the quartz veins segregated) melted in the silica‐undersaturated field producing a range of assemblages including peritectic corundum and spinel. Melting of the silica‐undersaturated rocks produced only negligible melt and no subsequent melt loss.  相似文献   

Sorption Characteristics of Rare Earth Element Eu^3＋ onto Silica-Water Interfaces Studied by Fluorescence Spectroscopy     

Yin Xiulan China Institute of Geo-environmental Monitoring  Beijing  China Hu Ping Faculty of Earth Sciences  China University of Geosciences  Wuhan  China  Northeastern Illinois University  Chicago  IL  USA Li Dien Division of Earth  Environmental Sciences  Los Alamos National Laboratory  Los Alamos  NM  USA 《中国地质大学学报(英文版)》2004,15(4):355-360

The sorption of Eu species onto nano-size silica-water interfaces was investigated using fluorescence spectroscopy for Ph ranges of 1-8.5 and an initial Eu concentration (Ceu) of 2×10-4 M. The sorption rate of Eu was initially low, but significantly increased at Ph>4. The sorption density of Eu species on a silica surface was ～1.58×10-7 mol/m2 when the dissolved Eu species were completely sorbed onto silica-water interfaces at Ph=～5.8. The sorbed Eu species at Ph<6 is aquo Eu3 , which is sorbed onto silica-water interfaces as an outer-sphere complex at Ph<5, but may be sorbed as an inner-sphere bidentate complex at 5相似文献   

Sorption of Eu~(3+) onto nano-size silica-water interfaces     

HU Ping    YIN Xiulan  ZHAO Linghu & LI Dien . Department of Earth Sciences  China University of Geosciences  Wuhan  China  . Northeastern Illinois University  Chicago  IL  USA  . China Institute of Geo-Environmental Monitoring  Beijing  China  . Division of Chemistry  Los Alamos National Laboratory  Los Alamos  NM  USA 《中国科学D辑(英文版)》2005,48(11)

A large amount of nuclear wastes has been pro-duced due to nuclear weapon development and nuclear electricity generation. One possible resolution for the disposal of the nuclear wastes is to seal them in an underground repository, which requires detailed knowledge on the mobility, chemical behavior and immobilization of radionuclides in underground water. In addition, toxic heavy metals are extensively present in ground and underground water, how to immobilize and remedy these toxic heavy meta…  相似文献   

HOLOCENE CLIMATE VARIABILITY IN THE DENMARK STRAIT REGION - A LAND-SEA CORRELATION OF NEW AND EXISTING CLIMATE PROXY RECORDS     

CAMILLA S. ANDRESEN  SVANTE BJORCK 《Geografiska Annaler: Series A, Physical Geography》2005,87(1):159-174

ABSTRACT. Two well dated Holocene sediment records bordering the Denmark Strait region have been used to reconstruct past climate variability. The content of biogenic silica, classic and organic material and moss in a lacustrine record from Lake N14 has been used to infer past variability in precipitation and temperature in southern Greenland. Sedimentologic and petrologic composition of sand in a shelf sediment record from the Djúpáll trough is used to infer past variability in the northwestern storm activity on northwestern Iceland, which probably also affected the inflow of polar waters from the East Greenland Current. Our evaluation of these records with a number of previous studies from the region documents Holocene climatic optimum conditions peaking between 8000 and 6500 calendar years before present (cal yr BP). Mid-Holocene climate deterioration set in around 5000 cal yr BP followed by a further marked setback around 3500 cal yr BP. A stacking of climate variability on a centennial timescale from previous studies in the area shows a fairly good correspondence to the timing of marked cold and warm events as evidenced from the Lake N14 and the Djúpáll trough records. Cooler periods are explained as the response to marked incursions of ice-laden polar water from the Arctic Ocean to the Denmark Strait region. Cool northerly and northwesterly winds along the East Greenland coast in relation to frequent strong atmospheric low pressure in the Barents Sea, coupled with strong high pressure over Greenland, would have favoured southward export of polar waters. A comparison with the proxy records of nuclide production (¹⁴C and ¹⁰Be) suggests that solar activity may have had some influence on the atmospheric pressure distribution in the Denmark Strait region.  相似文献   

Evidence for a shock-metamorphic breccia within a buried impact crater,Lake Raeside,Yilgarn Craton,Western Australia     

A. Glikson  A. Hickman  R. Crossley 《Australian Journal of Earth Sciences》2016,63(1):99-109

Mineral exploration drilling 60 km west of Leonora in 2008 intersected >95 m of poorly consolidated granitoid-dominated breccia at the base of a Cenozoic paleochannel beneath Lake Raeside. The breccia, initially interpreted as a kimberlite, is composed of poorly consolidated fragments of granitic gneiss, felsite and metamorphosed mafic rock within a matrix of fine to medium-grained breccia. Microscopic examination revealed quartz grains displaying well-developed planar deformation features (PDFs) dominated by the ω? {1013} planar set, diaplectic silica glass and diaplectic plagioclase glass. These features constitute the diagnostic hallmarks of shock metamorphism owing to high-velocity impact of a large meteorite or asteroid. The PDFs in quartz grains of the breccia are distinctly different from metamorphic deformation lamellae produced tectonically or in diatremes. Airborne total magnetic intensity data suggest an outline of an 11 km-diameter crater, consistent with the significant thickness of the shock-metamorphosed breccia at >95 m, suggestive of the existence of a large impact structure.  相似文献   

新疆三塘湖盆地马朗凹陷中二叠统芦草沟组泥页岩层系SiO2赋存状态与成因     

刘国恒  黄志龙  郭小波  刘再振  高潇玉  陈常超  张成林  王昕 《地质学报》2016,90(6):1220-1235

为了弄清新疆三塘湖盆地马朗凹陷芦草沟组泥页岩层系中SiO_2对储集层物性、脆性等特性的影响,通过全岩和黏土矿物X衍射、岩石力学性质、阴极发光、扫描电镜及电子能谱等实验手段对其中SiO_2的赋存状态进行了研究,初步探讨了SiO_2不同形态赋存的机理,并在此基础上探究了石英含量对储层的影响。研究表明:凝灰岩、泥页岩和粉砂质泥岩中二氧化硅多以非晶态形式存在。二氧化硅在凝灰岩中多呈不规则球粒状,而在泥页岩和粉砂质页岩中无固定形态。凝灰质泥岩、凝灰质白云岩和白云岩中二氧化硅呈现一定的晶体形态。在凝灰质泥岩中,二氧化硅以自生石英形态聚集呈条带状,在凝灰质白云岩中则以自生石英形态发育于孤立的孔、洞之中,而白云岩中二氧化硅只能生长成Opal-A/Opal-CT阶段。凝灰质成分及其脱玻化作用为自生石英的生长提供了二氧化硅和生长空间,是控制SiO_2赋存状态的根本因素。此外,储集层孔隙度、渗透率和抗压强度都与石英含量呈一定正相关性,泊松比则与其呈负相关性。  相似文献   

南极普里兹湾表层沉积物微量元素分布特征及其物源指示意义   总被引：1，自引：0，他引：1  

孙维萍  扈传昱  韩正兵  翁焕新  陈际雨  潘建明 《沉积学报》2016,34(2):308-314

利用电感耦合等离子体质谱仪测定了中国南极科考21~27航次期间获取的普里兹湾表层沉积物中Cu、Pb、Zn、Cd、Cr、Co、Al、Fe、Mn的含量,分析了普里兹湾微量元素的分布特征,结合沉积物粒度分布、生物硅含量,并利用富集系数和主成分分析的方法,探讨了微量元素的物源指示意义。研究结果表明:普里兹湾沉积物中的微量元素含量与南大洋其他海域具有很好的可比性。Cu、Zn、Cr、Co、Fe、Mn含量在陆坡深海区明显高于冰架边缘区和陆架区;Al、Pb含量在冰架边缘区较高;而Cd含量在陆架区相对较高。人类活动对普里兹湾沉积物中的微量元素没有明显的影响,南极大陆岩石风化产物和海洋生物源性沉降是其主要来源。冰架边缘区及陆架破折处P2-9站位的微量元素主要为岩源性输入。陆架区、陆坡深海区的微量元素Cu、Zn、Cr、Co、Fe、Mn明显受到生源性物质输入的影响。而普里兹湾沉积物中Cd则主要来源于硅藻的吸收利用及硅质软泥的富集。  相似文献   

Reply to Sandgren and Smol: further discussion on chrysophyte cyst taxonomy     

Heikki Simola 《Journal of Paleolimnology》1993,9(1):63-68

  相似文献