东秦岭造山带“两阶段双带”区域成矿模式

TWO STAGES AND PAIRED BELTS" MODEL FOR REGIONAL MINERALIZATION IN EASTERN QINLING OROGENIC BELT

东秦岭造山带总体上可划分为中元古代—古生代主要与裂谷、坳陷槽有关的海盆同生沉积成矿以及中生代与大规模陆内俯冲造山体制有关的后生热液成矿两大阶段 ,且中生代所形成的浅成和中深成两类热液矿床在横向上分带并呈相邻平行展布 ,成对共生 ,构成双成矿带 ,其形成机制是扬子地块及华北地块分别往秦岭发生陆内俯冲 ,使与挤压、转换挤压—变质变形、深成侵入—深源流体成矿系统有关的中深成热液型矿床形成于仰冲板片前缘的推覆—隆升带中 ;而使与伸展—高地热场 (火山、浅成侵入 )—地热流体成矿系统有关的浅成热液型矿床形成于推覆—隆升带后侧的同碰撞伸展带中。

This paper sets up and illustrates 'two stages and paired belts' model for regional mineralization in Eastern Qinling. It is pointed out that mineralization in this area can be generally divided into two stages:Meso-Proterozoic-Palaezoic syndepositional mineralization stage in sea basins related to rift valleys and geotectogenes, and Mesozoic epigenetic-hydrothermal metallogenic stage in the large-scale intracontinental subduction orogenic system. It is discovered that the Mesozoic hydrothermal ore deposits have characteristics of horizontal zoning and paragenesis in paired belts of epizonal and mesozonal types. It is assumed by the authors that the intracontinented subduction of the Yangtze and North China blocks to Qinling mountains resulted in the formation of mesozonal-hydrothermal deposits related to compression and transpression-metamorphism, deformation and plutonic intrusion-deep-rooted hydrothermal metallogenic system within thrust-uplift zones at the fronts of the overthrust slaps.Meanwhile it caused epizonal hydrothermal deposits related to extension-high geothermal field(generally with volcanism and/or shallow intrusion)-geothermal fluid metallogenic system within syncollision extension zones behind the thrust-uplift zones.