新疆阿图什彻依布拉克锡多金属矿点地质特征

GEOLOGICAL CHARACTERISTICS OF QIEYIBULAKE TIN-POLYMETALLIC ORE SPOT IN ATUSHI CITY, XINJIANG

南天山是重要的锡锑多金属成矿带,目前已发现几处锡矿床(点)和大量锡化探异常,具有良好的成矿前景.彻依布拉克锡多金属矿点赋存于塔木岩体围岩的夕卡岩中.塔木碱长花岗岩侵入时代为晚二叠世,化学成分具有富Si、富碱,贫Mg、Al的特点,Ga/Al比值大,富轻稀土,具强Eu负异常,具有A型花岗岩的特点.矿体严格受夕卡岩带控制,呈似层状、透镜状,与夕卡岩产状一致,二者呈渐变过渡关系,矿体变化较大.矿石类型有:锡铁矿石、金(铜)矿石、锡矿石和锌铜矿石.成矿具有多阶段性,划分为夕卡岩阶段、硼酸盐阶段、硫化物阶段和表生阶段,其中硼酸盐阶段是锡成矿的主要阶段.岩浆活动为成矿提供了热源和主要物质来源.

Southern Tianshan Mountains in Xinjiang is an important tin-polymetallic metallogenic belt and a promising exploration area where several tin deposits (ore spots) and many geochemical anomalies were found by now. Qieyibulake tin-polymetallic ore spot occurs in skarn of contact zone of wall rock and Tamu pluton. Intrusive age of Tamu alkali feldspar granite is Upper Permian. Geochemically the Tamu pluton is rich in Si, alkali, REE, Li, Rb, Be, Nb, Zr, Th, W, Sn, Pb, Ga, poor in transitional element like Mg, Al, Cr, Co, Ni, V etc. and with high Ga/Al ratio. It is rich in light REE (LREE) with intensive europium depletion, and belongs to A-type granite. Orebody , showing bed-like and lenticular, are contolled by skarn belt and of the same attitude with skarn. Orebody vary greatly and gradually change to skam. Ore types include tin-iron ore, gold(copper)ore, tin ore and zinc-copper ore. The ore-forming process is characterized by multi-stages and four stages can be identified. They are skarn stage, borate stage, sulphide stage and supergene stage, among which borate stage is the main tin metallogenic stage. Magmatic activity provided heat and main original materials for mineralization.