| 中国大连地区发现含稀土和贵金属矿物组合的新元古界变泥岩 |
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| 引用本文： | 宋天锐,石玉若.中国大连地区发现含稀土和贵金属矿物组合的新元古界变泥岩[J].沉积学报,2012,30(4):603-618. |
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| 作者姓名： | 宋天锐 石玉若 |
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| 作者单位： | 中国地质科学院地质研究所,北京,100037 |
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| 基金项目： | 国家自然科学基金项目，国家自然科学基金委员会的资助，基本科研业务费(No.J1115)的资助
致谢本文的研究工作得到国家自然科学基金委员会的资助，以及基本科研业务费(No.J1115)的资助;并感谢大连金石滩景区管理委员会在研究工作中给予的帮助 |
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| 摘 要： | 论述一种非常窂见的轻微变质的新元界变泥岩，其中含有碎屑的和自生-成岩的独居石和磷钇矿颗粒以及自然金、锇-铱、铱、锌金属等；还有锆石、金红石，磷灰石、钛铁矿、赤铁矿等重矿物，并伴生少量黄铜矿、斑铜矿、方铅矿等硫化矿物。该变泥岩产于大连金石滩，属于新元古界震旦系十三里台组，是由红色叠层石灰岩和绿色变泥岩互层组成。按照岩石的结构、构造和沉积相标志分析，其沉积环境属于碳酸盐近岸礁滩平原地带的局限盆地，其封闭区域内还原和氧化的化学环境交替出现，细小的碎屑独居石、磷钇矿颗粒以及自然金、锇-铱、铱、锌金属等伴生出现，创造了有利于稀土元素矿物分解和再沉积，在同生沉积和成岩阶段中形成了自生独居石（“人形的”、“鸟形的”）和磷钇矿（“猫形的“）。然而贵金属矿物都是碎屑成因的，至于黄铜矿、斑铜矿方铅矿以及锌金属微细脉有可能与后期的流体矿化活动有关。本文认为华北地台的元古宙地层含有较丰富的稀土元素和贵金属，是新元古界变泥岩中所含稀土元素矿物和贵金属的原始来源地。此外，还讨论了独居石和磷钇矿的SHRIMP测年问题。
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| 关 键 词： | ,新元古界,独居石、磷钇矿,贵金属,变泥岩,SHRIMP测年 |
Discovery of A Neo-Proterozoic Pelite Bed Containing REE and Noble Metal Mineral Assemblages from the Dalian Area,China |
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| SONG Tian-rui,SHI Yu-ruo.Discovery of A Neo-Proterozoic Pelite Bed Containing REE and Noble Metal Mineral Assemblages from the Dalian Area,China[J].Acta Sedimentologica Sinica,2012,30(4):603-618. |
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| Authors: | SONG Tian-rui SHI Yu-ruo |
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| Institution: | (Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037) |
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| Abstract: | Neo-Proterozoic Sinian System of the Dalian District where is the only one outcrop area in North China,is recognized as a geo-nappe from South China Sinian System.The Sinian strata in the tourist scenic area of Golden Stone Beach area are composed of 7 formations(in ascending ward): the Yingchengzi(Z2y),the Shisanlitai(Z2s),the Majiatun(Z2m),the Cuijiatun(Z2c),the Zhoujiaweizi(Z2z),the Wangjiatan(Z2w),and the Xingmingchun(Z2x). REE minerals and noble metals bearing pelite is included in the Shisanlitai Formation which consists of rose colored stromatolite carbonate beds therefore the tourist scenic spot be named "Rose Garden" in the Goldstone Beach Scenic District.There are several greenish pelite beds where monazite and other REE minerals are found in the Shisanlitai Formation.Two beds among them are relative thicker than other,and more metal minerals are discovered. According to the change of ratio of FeO/Fe2O3 in strata,the main body rock of pink stromatolite limestone occurred in an oxidizing environment,however the greenish pelite in a reducing environment of a locally restrict area.Besides,a comparison of light rare earth elements(LREE) with North American Shale(NASC) shows that greenish pelite contains more LREEs but pink stromatolite limestone consists of less these elements than NASC.Further distinguished by three end-member diagram(La+Ce+Nd,Sm+Gd+Dy,and Yb+Y),the sediments deposited location of distance from marine beach shows that the greenish pelite beds should be near continent,but the pink stromatolite limestone be far away from continent. This paper issues a very rare slight metamorphosed Neo-Proterozoic pelite,which includes clastic and authigenic-diagenetic monazite,xenotime grains,as well as native gold,Ir-Os,Ir metal grains,zircon,rutile,apatite,ilmenite,hematite etc.heavy mineral associations,and some rock forming minerals.The pelite beds belong to Neo-Proterozoic Sinian System,the Shisanlitai Formation,which are composed of the interbedded reddish stromatolite limestone and greenish pelite intercalations.The sedimentary environmental textural facies indicators shows that there were a carbonate shore reef regions near the continent in the Shisanlitai Stage,which involves some like-lagoon restrictive small basins under the reduction and oxidation alternation chemical condition and creates the favorable micro-environment for REE molecular exchanging to the authigenic-diagenetic monazite("man-shaped","bird-shaped") and xenotime("cat-shaped") in the syngenetic deposition and diagenetic stages.The noble metal grains are mainly clastic origin,but Au,Zn,Cu and Pb are related with ore-made fluid.North China platform with the abundant REE elements and the noble metals is the original source of the Neo-Proterozoic REE minerals-noble metals bearing pelite. |
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| Keywords: | Neo-Proterozoic authigenic-diagenetic REE minerals noble metals pelite Dalian |
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