白云鄂博碳酸岩墙的稀土和微量元素地球化学及对其成因的启示  

Geochemistry of REE and other trace elements of the carbonatite dykes at Bayan Obo: implication for its formation.

作　　者：王凯怡[1] 范宏瑞[1] 谢奕汉[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《岩石学报》2002年第3期340-348,共9页Acta Petrologica Sinica

基　　金：国家自然科学基金 (批准号 :49972 0 3 6);国家科技攀登项目 ( 95 -预 -2 5 -0 1)资助

摘　　要：根据矿物组成白云鄂博矿区的碳酸岩岩墙可分为白云石型、白云石 -方解石共存型和方解石型三种类型。 REE和微量元素地球化学表明 ,这三类碳酸岩岩墙为碳酸岩浆演化不同阶段的产物 ,白云石型和白云石 -方解石共存型对应于早期岩浆阶段 ,其 (L a/ Nd) n、(L a/ Y) n 和 (L a/ Yb) n 比值随稀土总量的增加而增大 ;方解石型则对应于碳酸岩浆演化的晚期热液阶段 ,其稀土总量明显富集 ,但其 (L a/ Nd) n、(L a/ Y ) n 和 (L a/ Yb) n 比值随稀土总量的增加却有减小的趋势 。According to mineralogical composition carbonatite dykes at Bayan Obo REE-Fe-Nb deposit, Inner Mongolia, can be divided into three types: the dolomite type, the dolomite-calcite type and the calcite type. Based on the REE and trace element geochemistry of three types of the carbonatite dykes, they may correspond with the different evolutionary stages of the carbonatite magmatism. The dolomite and dolomite-calcite types correspond to the early stage of the carbonatite magmatism, with increasing REE contents the ratios of (La/Nd)(n), (La/Y)(n) and (La/Yb)(n) increasing. Whereas the calcite type highly enriched in total REE contents corresponds to the late hydrothermal stage of carbonatite magmatism, with increasing REE contents the ratios of (La/Nd)(n), (La/Y)(n) and (La/Yb)(n) are decreasing. This is also concordant with the major REE mineralization stage of the Bayan Obo deposit.

关 键 词：碳酸岩岩墙 岩浆成因 热液成因 元素地球化学 白云鄂博矿区 稀土元元素 

分 类 号：P588.15[天文地球—岩石学] P595[天文地球—地质学]