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中国大型煤-锗矿床成矿模式研究进展:以云南临沧和内蒙古乌兰图嘎煤-锗矿床为例
Progress of research on mineralization mode of large coal-Ge deposits in China:Coal-Ge deposit in Wulantuga of Inner Mongolia and Lincang of Yunan
【摘要】 锗元素是研究得最多也是开发利用最好的煤中可利用伴生元素。在自然界中所有的煤都含有锗,但是能富集成锗矿床的只是极少数,多数煤中锗含量甚微。中国目前已发现的具有开采价值的煤-锗矿床有两个,分别是位于云南西部的新生代盆地的临沧煤-锗矿床和内蒙古的中生代盆地的乌兰图嘎煤-锗矿床。但这两个煤锗矿床地质因素各有不同,文中对其不同点进行了比较。中国云南省煤中含锗的情况最为丰富多样,其研究程度较高,处于成熟开发阶段。云南省西部含有富锗煤的新生代盆地的基底都是可提供丰富锗源的花岗岩。盆地内煤中锗分布不均一与两类花岗岩提供的锗源有一定关系。内蒙古胜利煤田内富锗煤矿床正处于开发阶段。矿产地西部附近出露二长花岗岩和闪长岩为主要的锗源供给。胜利煤田和伊敏煤田煤中锗的赋存状态和地质条件与临沧的差异较大。二连盆地群与煤油气相关的地质研究成果较为丰富,如果进一步开展普查找矿工作,将有可能发现新的矿点。
【Abstract】 Germanium is the most researched and best-developed available associated element in coal.All of coal in the nature has Ge,while a tiny minority can accumulate commercially and most has little Ge.The average mass fractions of Ge in coal in China,USA,Australia,UK and former Soviet Union are 3.6×10-6,5.7×10-6,2.9×10-6,4.4×10-6,and 1.5×10-6,respectively.n×100×10-6 is high anomaly in Ge content.Two commercially-exploited coal-Ge deposits have been found in China,namely,Cenozoic basin in western Yunnan Province and Mesozoic basin in Inner Mongolia Autonomous Region.But the geological factors of two basins are different.In the article,we mainly compare two basins unique features respectively.The situation of Ge in coal in Yunnan Province is abundant and in the stage of mature development.The known reserve is high to 800 tons in Bangmai Basin in Lincang County,which belongs to extra-large Ge deposit.The approximate area is 16.4km2 of Bangmai Basin,which is a small-scale Neogene faulted basin.The Ge distributions in each coal seams are not extremely even.Ge in coal generally occurs at the bottom of coal seams in the formation and at the margins of basins in planar surface.The basement of these Neozoic basins in western Yunnan Province can supply granite which is rich in Ge.The average Ge value in binary granite distributed in western Bangmai Basin is 3.5×10-6,and biotite granite in the east is 1.7×10-6,which uneven distribution is related with the different Ge sources supplied by two types of granite.Ge,which was released from source rocks,went into the solution,and flowed into coal-bearing basins through favourable palaeo-hydrologic geological conditions.The coal-Ge deposit in Shenli coalfield in Inner Mongolia is in the stage of development.Monzonitic granite and diorite outcrop in western mineral land have high Ge value above 15×10-6 after sampling and testing.A bulk of active germanium was released from these rocks by oxygenolysis and decomposition,dissolved in the form of germanium acid solution and migrated into coal basins.Ge abundance increases in upper coal seams because Ge dissolved in hydrothermal fluid in thermometamorphic process and migrated upward.And it decreases near surface because of subsurface water leaching and migration downward.The result generated by the two migrations is that the Ge enriched zone formed between lower bituminous coal and low metamorphic coal near surface(volatile separated rate is above 37%),in which the average Ge value is 15×10-6 and the maximumvalue is high to 450×10-6.The Ge enrichment and geological factors in Shengli and Yimin coal fields,Inner Mongolia have great difference with those in Lincang County,Yunnan Province.It may be found new mineral occurrences in further general investigation and exploration in Erlian Basin Group which has semigraben basin,graben basin,faulted-depressed basin and contains affluent coal,oil and natural gas.The geological research outcomes related with coal and petroleum are abundant,which is a perfect basis for advanced research on coal-Ge deposits in basin groups.
【Key words】 germanium; coal-Ge deposit; metallogenic model; occurrence;
- 【文献出处】 地学前缘 ,Earth Science Frontiers , 编辑部邮箱 ,2016年03期
- 【分类号】P618.11;P618.75
- 【被引频次】32
- 【下载频次】725