江苏溧水卧龙山锶矿床地质特征及找矿方向

Geological characteristics and prospecting direction of Wolongshan strontium deposit in Lishui area,Jiangsu Province

卧龙山锶矿床是江苏省溧水盆地内新发现的热液充填型锶矿床,目前控制规模为中型。矿床地质特征研究表明,卧龙山锶矿床矿体的赋存位置及产状均严格受NW向断裂构造的控制;矿石自然类型以致密块状矿石为主,矿石结构以自形板片状为主,矿石构造以块状、角砾状和网脉状为主;围岩蚀变表现为中低温热液蚀变特征,且沿矿区NW向断裂呈线状分布。根据矿物的世代和穿插关系,将锶矿化划分为天青石-黄铁矿阶段、天青石阶段和方解石-天青石阶段。查明了矿区NW向构造是主要控矿因素,亦是主要找矿标志,而NE向构造是破矿构造。提出了矿区NW向构造是区域主干断裂右行扭动所派生的次级断裂构造;而NE向构造是区域主干断裂左行扭动所派生的次级断裂构造;认为矿区锶矿化发生在主干断裂右行扭动之后,左行扭动之前,并赋存在右行扭动派生的NW向断裂构造中。因此,溧水盆地锶矿勘查重点(找矿方向)应沿着开太-白马山主干断裂开展,找寻其右行扭动派生的NW向构造。

The Wolongshan strontium deposit is a hydrothermal-filling type medium-sized strontium deposit recently discovered in the Lishui volcanic basin. The distribution and attitude of the orebodies are controlled by NW- striking faults. The main type of the ore is massive, the dominant texture is in euhedral-granular form, and the ore structure consists mainly of massive, brecciform and stockwork forms. The hydrothermal alteration is characterized by middle-low temperature alteration controlled by the NW-trending faults. The generation and penetrating relationship of minerals show that the ore-forming process of the Wolongshan deposit could be divided into three stages： celestite-pyrite, celestite and caleite-celestite stages. Detailed geological mapping confirms that the NW-trending structure is the main ore-bearing structure, and the NE-striking structure is the orebreaking structure. The NW-striking fault was formed by the right twisting of the Kaitai-Baimashan fault, while the NE-striking fault was generated during the left twisting. Sr mineralization occurred after the right twisting of the Kaitai-Baimashan fault but before the left twisting, and was distributed in the NW-striking faults formed during the right twisting. This study suggests that the exploration of Sr deposit in the Lishui basin should be focused on the Kaitai-Baimashan fault, and the search for the right twisting derived NW-striking faults might be the prospecting direction in the future.