吐拉苏盆地高硫型浅成低温热液金矿化的识别

The Tulasu basin, located in the north part of the Yili Block, is the largest epithermal gold province of Xinjiang. The epithermal deposits were mainly formed between Carboniferous and Permian, earlier than those in the Circum-Pacific and Tethyan metallogenic belt. Genetically, they are mainly of low sulfidation type, whereas whether there are high sulfidation epithermal deposits is still hotly debated. The Jingxi-Yelmand large gold deposit was once regarded as high sulfidation epithermal deposit, but was debated by the occurrence of both advanced argillization and sericitization. To settle such dispute, detailed geological observation and alteration mapping would be employed, and the ore-controlling factors, the lateral and vertical distribution of alteration and mineralization, can be identified. Combined with fluid inclusion and isotopic studies, the genetic type of advanced argillization (hypogene vs steam-heated vs supergene), and its temporal and spatial relationship with sericitization can be constrained, so does the genetic of the deposit. The potential achievement cannot only improve our understanding of epithermal deposits in the Tulasu basin, but also is beneficial to the exploration and evaluation in this area.

吐拉苏盆地地处伊犁地块北缘，是新疆最大的浅成低温热液金矿富集区，以发育古生代浅成低温热液系统和特殊的保存条件为特色。目前认为其浅成低温热液矿床以低硫型为主。而京希-伊尔曼德金矿曾被认为高硫型矿化，但因同时报道有高级泥化和绢云母化受到质疑。本申请拟通过系统的野外地质观察和蚀变填图，研究控矿地质要素、矿体定位，围岩蚀变类型和水平、垂向分布特征，矿石矿物成分、组构及空间变化，成矿流体性质及成矿物质来源，探索高级泥化蚀变成因（深成成因、蒸汽加热成因或表生成因）及其与绢云母化的时空关系，厘定矿化作用类型，深化对吐拉苏盆地浅成低温热液成矿规律的认识，为找矿勘查提供导向。

吐拉苏盆地地处伊犁地块北缘，是新疆最大的浅成低温热液金矿富集区，以古生代浅成低温热液矿床的形成和保存为特色。已有研究认为其浅成低温热液矿床以低硫型为主，是否存在高硫型尚存争议。本项目重点依靠系统的矿区地质野外调查和室内显微镜观察，研究了控矿地质要素、矿体定位，围岩蚀变类型和水平、垂向分布特征，并探索依据重要的载金矿物–黄铁矿（白铁矿）的形态和成分特征推测成矿时的物理化学条件，揭示了成矿机理。发现阿希、小于赞属低硫型，京希-伊尔曼德为高硫型，库茹尔可作为高硫型与斑岩型之间的过渡类型。通过地质年代学和热年代学相结合的方法约束了矿床隆升剥露作用时限及程度，探讨了古老造山带中浅成低温热液矿床的保存机理。发现了赋矿火山岩中的不平衡结构，揭示了中酸性火山的岩浆混合成因，认为多次的岩浆补给有利于大型、超大型矿床的形成。