西昆仑笔架山铷矿地质特征及找矿方向

Geological Characteristics and Prospecting Direction of Bijiashan Rubidium Deposit in West Kunlun

铷是重要的稀有金属和战略性新兴矿产。我国铷矿主要类型为花岗岩型和花岗伟晶岩型。近期新疆地质调查院在西昆仑大红柳滩东笔架山发现一处花岗斑岩容矿铷矿床。据野外调查笔架山含铷岩体由二个侵入体组成,长1.9 km,宽0.85 km,比高约390 m。岩石薄片鉴定岩性为正长花岗斑岩,与区域地质调查成果资料一致。岩石具典型斑状结构,块状构造。岩石中斑晶含量高,以透长石为主。基质粒径较细,主要矿物为长石和石英,多呈它形粒状,发育次生白云母。基质中长石具较明显粘土化,具超浅成岩或次火山岩特征。据主量、微量元素分析,岩石中里特曼指数σ=2.34~2.55,为碱性岩,据Na_(2)O-K_(2)O图解属“A”型花岗岩类。通过对100余件化学样品分析,样品铷品位大于0.1%,获得Rb_(2)O平均品位0.13%~0.26%,伴生Li_(2)O品位0.07%~0.16%,显示该花岗斑岩具全岩铷矿化特征。据对地表含矿岩体控制,初步估算Rb_(2)O潜在资源量33.8×10^(4)t,伴生Li_(2)O潜在资源量17.0×10^(4)t,具超大型铷矿规模远景,西昆仑稀有金属矿找矿线索进一步扩大。

Among many rare metal resources,rubidium is an important rare metal and strategic emerging industrial mineral.There are two types of rubidium deposits in China:granite type and granite pegmatite type.Recently,Xinjiang Geological Survey Institute discovered an important granite porphyry host rubidium deposit in Bijiashan,Dahongliutan,West Kunlun,which has a very large scale prospect.According to field investigation,Bijiashan Rb bearing rock mass is composed of two intrusions,It is 1.9 km long,0.85 km wide and 390 m high.According to the thin section of the rock,it is identified as syenite granite porphyry,which is consistent with the regional geological survey results.The rock has typi-cal porphyritic texture and massive structure,with high content of phenocrysts and mainly sanite;the grain size of the matrix is fine,and the main minerals are feldspar and quartz,which are mostly xenomorphic granular,with some second-ary muscovite.The feldspar in the matrix is obviously clayed and has the characteristics of ultrahypabyssal rock or subvo-lcanic rock..Through the analysis of more than 100 chemical samples,the Rb grade of all the samples is more than 0.1%,the average grade of Rb_(2)O is 0.13%~0.26%,and the grade of associated Li_(2)O is 0.07%~0.16%,which shows that the granite porphyry has the characteristics of whole rock Rb mineralization.According to the control of ore bearing rock mass on the surface,it is preliminarily estimated that the potential resource of Rb_(2)O is 338000 tons,and the potential re-source of Li_(2)O is 170000 tons.It has the prospect of super large scale rubidium deposit and expands the prospecting clues of rare metal deposits in West Kunlun.