藏北班公湖—怒江缝合带中—西段康穷地区发现铬铁矿

The discovery of chromite in the Kangqiong area, middle-western segment of the Bangong Co-Nujiang River suture zone

班公湖—怒江缝合带中—西段康穷地区发育一套各端元出露比较齐全的蛇绿岩岩石组合,向东与八乌错、米素、赤日、孜如错、桑日一带的超基性岩共同构成了班公湖—怒江缝合带中—西段基性超基性岩带。2012年,于康穷地区变质橄榄岩岩体边部发现一处铬铁矿体,首次证实这一巨大的超基性岩带内存在铬铁矿。铬铁矿露头良好,地表见有2条矿体,在露头西侧还见有大片残坡积铬铁矿,残坡积之下的深部情况尚难确定。矿体以冶金级富铬矿石为主,Cr2O3含量最高可达59.11%,矿体围岩主要为方辉橄榄岩,见有少量纯橄榄岩。初步研究认为,康穷铬铁矿类型为豆荚状铬铁矿。该矿体的发现为班公湖—怒江缝合带中—西段铬铁矿的找矿工作提供了重要线索,对区域找矿具有重要的指示意义。

There occurs a complete assemblage of ophiolites in the Kangqiong area along middle-western Bangong Co-Nujiang River suture zone. It is about 40 kilometers from Dongco ophiolite, and associated with ultramafic rocks along Bawuco, Misu, Ziruco and Sangri areas in the east. All of these areas constitute a part of middle-western Bangong Co-Nujiang River mafic-ultramafic rock zone extending for about 300 kilometers. Chromite orebodies produced at the edge of metamorphic peridotite rock were found in 2012, and it is the first time to confirm that there occurs chromite in this huge mafic-ultramafic rock zone. The chromite has good outcrops and belongs to two orebodies, and there probably exists much chromite at the depth of the outcrops. The orebodies are dominated by metallurgical-grade chromium ore, the Cr2O3 content of ore samples is up to 59.11%, and the ore-bearing bodies consist mainly of FAI peridotite, together with a small amount of dunite. Preliminary studies suggest that the Kangqiong chromite is podiform chromite. The results achieved by the authors have an indicative significance for regional chromite exploration.