古生—中生代秦岭造山带发展演化与金属成矿作用

EVOLUTION OF QINLING PALEOZOIC-MESOZOIC OROGENIC BELT AND METAL METALLIZATION

秦岭造山带的形成、发展、演化可分成３ 个阶段：１） 晚太古代－ 古元古代，造山带前寒武纪基底的形成演化（３ ．０ ～１ ．６ Ｇａ） ；２） 新元古代－ 中三叠世，以现代板块构造体制为基本特征的板块构造演化（０ ．８ ～０ ．２ Ｇａ） ；３） 中新生代陆内造山作用与构造演化。而晚古生代早期（Ｄ） 和中生代早期（Ｔ） 则是造山带演化的关键转折期，即秦岭微板块的游离和由挤压变为拉张状态（Ｄ） 以及板块的对接碰撞并转入陆内造山（Ｔ） ，而这两个时期也是秦岭造山带金属大量聚集的时期，形成了泥盆纪大规模Ｓｅｄｅｘ 型铅锌（ 铜） 银矿床和印支－ 燕山期大量沉积岩型（ 微细浸染型） 金矿床及沉积改造型铅锌汞锑（ 金） 矿床。同时探讨了地质事件与成矿事件的耦合及二者之间的关系。

The forming, developing and evolving of the Qinling orogenic belt is divided into three stages: (1)the forming and evolution of Precambrian basement in Upper Achaeozoic-Lower Proterozoic (3.0～1.6Ga); (2) Upper Proterozoic-Middle Triassic plate tectonic evolution featuring modern plate tectonic mechanism (0.8～0.2Ga); (3)Mesozoic-Cenozoic intracontinental orogeny and tectonic evolution. The early Upper Paleozoic (D) and early Mesozoic (T) represent the key periods of orogenic belt (transformation of compression to extension due to freeing of microplates in Qinling and intracontinental orogeny due to joint and collision of plates. The two periods involve the enrichment of massive metals, forming of the Devonian Sedex-type Pb-Zn deposits, Indosinian-Yanshannian disseminated gold hosted in sediments and sedimentary-reformation type Pb-Zn-Hg-Sb deposits. As one of the geological events, the metallogenic events are controlled by the geological events.