西藏喜马拉雅成矿带东段嘎波伟晶岩型锂矿的发现及其意义

Discovery of the Gabo granitic pegmatite-type lithium deposit in the Kulagangri Dome, eastern Himalayan metallogenic belt, and its prospecting implication

库拉岗日穹窿位于西藏喜马拉雅成矿带的东段,北邻拉隆穹窿。通过1∶5万矿产地质填图和稀疏地表工程控制,在库拉岗日穹窿东部的嘎波地区新评价一处伟晶岩型锂矿。含矿锂辉石伟晶岩脉整体上顺层出露在穹窿滑脱系大理岩中,单条脉长1~1 200 m不等、宽0.8~40 m不等,主要含锂矿物有锂辉石、锂电气石和锂云母等。目前通过5个地表工程控制识别出2条主要矿化带,其中Ⅰ号矿化带长约2 km,圈出主矿体2条(K_(1)、K_(2)),Ⅱ号矿化带长约700 m,圈出主矿体1条(K_(3))。K_(1)矿体长约1 200 m,厚5~40 m,平均约20 m。K_(2)和K_(3)矿体呈大透镜状产出,走向延伸>100~600 m,厚15~50 m,其中K_(2)矿体总厚度45.3 m, Li2O平均品位为1.11%、Rb2O平均品位为0.064%、BeO平均品位为0.047%。新发现的嘎波锂矿以锂为主,共生铍、铷,伴生铌、钽、铯、钨、锡等有益组分,初步分析有望达到大型规模,进一步找矿潜力巨大。嘎波锂矿的发现是喜马拉雅成矿带稀有金属找矿取得的又一重大突破,对深入认识喜马拉雅新生代构造-岩浆演化与稀有金属成矿作用,进一步丰富和完善青藏高原南部碰撞造山与成矿理论具有十分重要的指导意义。

The Kulagangri Dome is located at the eastern part of the Himalayan metallogenic belt. Based on the 1∶50 000 mineral geological mapping and sparse surface engineering, the Gabo pegmatite-type lithium deposit was firstly found at the eastern part of the Kulagangri Dome. Ore-bearing spodumene pegmatite dikes are generally hosted by the marble in the middle unit of the dome, with length ranging from 1 m to 1 200 m, and width ranging from 0.8 m to 40 m. The main lithium containing minerals in the spodumene pegmatite are spodumene, elbaite and lepidolite. At present, two main Li mineralization zones are controlled by 5 surface engineering. The mineralization zone I is about 2 km long, and includes 2 main orebodies(K_(1)and K_(2)). The mineralization zone Ⅱ is about 700 m long, and include one main orebody(K_(3)). The K_(1)orebody is about 1 200 m long and 5~40 m thick, with an average thickness of about 20 m. The K_(2)and K_(3)orebodies occur as the large lenticular shape, with strike extension >100~600 m and thickness 15~50 m. The total thickness of K_(2)orebody is 45.3 m. The average grade of Li2O,Rb2O and BeO is 1.11%, 0.064% and 0.047%, respectively. The newly discovered Gabo lithium deposit is dominated by Li, Be and Rb, associated with Nb, Ta, Cs, W and Sn. Based on the geological survey results, the Gabo lithium deposit is large in scale, and showing considerable potential for further prospecting in the area. The discovery of Gabo lithium deposit is another breakthrough in the exploration of rare metals in the Himalayan metallogenic belt, which is of great significant role in further understanding of the tectono-magmatic evolution and rare metal mineralization in the Cenozoic Himalaya, and further enriching the theory of collisional orogenesis and mineralization in the southern Qinghai-Tibet Plateau.