秦岭成矿带成矿特征和找矿方向

秦岭成矿带是我国有色、贵金属工业的重要矿产资源基地,也是最具成矿潜力和找矿远景的地区之一。近年的综合研究工作表明,秦岭造山带是一个多旋回复合大陆碰撞造山带,自太古代以来经历了多种构造体制的转化和多期构造热事件发生,伴随有多个构造成矿旋回,所形成的含矿建造、成矿作用及矿床组合具有多样性。根据成矿时代、构造、建造、成矿作用及矿床组合特征分析,认为秦岭造山带铜、钼、铅、锌、银、金、汞、锑等内生金属矿床主要受7个主要的成矿系统控制,形成了18个主要成矿系列,并对各成矿系列及其典型矿床的地质特征和近几年找矿新发现进行了系统的论述,建立了铜、金、铅、锌、银等矿床系列的区域成矿模式。对区域优势矿种的成矿谱系研究表明,本区成矿在时间演化上表现出明显多旋回性、继承性、新生性和叠加性特征,华力西期与印支末-燕山期是成矿大爆发期,最有利于大型超大矿床形成;在空间分布上,具有明显的侧向和垂向分带性。在此基础上,对秦岭成矿带的成矿潜力及成矿远景区进行了评价和划分,指出秦岭地区热水喷流沉积型与密西西比型铅锌银矿床、微细浸染型与石英脉构造蚀变岩型金矿床、斑岩型钼钨铜矿床及低温热液型汞锑矿床等具有很大的找矿前景。并划分出5个区域成矿远景带和17个重要成矿预测区。

Mineralization Characteristics and Prospecting Potential in the Qinling Metallogenic Belt

The Qinling metallogenic belt is an important mining site for base and precious metals and also one of the most potential mineralization areas in China. The recent integrated studies show that the Qinling Mountains is a collisional orogen with polycyclic evolution and composite formations as well as mineralization. The characteristics of tectonic setting, lithological formation, association of ore deposits and metallogenic epoch indicate seven major minerogenetic systems and 18 minerogenetic series governing mineralization of Co, Mo, Pb, Zn, Ag, Au, Hg and Sb in the belt. This paper discusses the geological features for each minerogenetic series and its corresponding ore deposit, reviews the new discoveries in recent exploration and establishes the regional models for Cu, Au, Pb, Zn and Ag series. The study of the spectrum of ore deposits in the belt demonstrates that the regional mineralization is temporally characterized by polycycling, inheritance, neoformation and superimposition. The Variscan, late Indosinian to Yanshanian epochs are favorable periods to form large and giant ore deposits. Spatially, mineralization zoning in both vertical and lateral direction has been observed. Also, this study evaluates the Qinling metallogenic belt in terms of ore-forming potential and prospecting areas and concludes that prospective deposits are SEDEX and MVT types of Pb and Zn, vienlet-disseminated type and quartz vein altered type Au, porphyry type of Mo, W and Cu and epithermal Hg and Sb in the belt. Finally, 5 regional prospecting zones and 17 important potential areas have been determined.