秦岭勉略构造带组成、变形特征及与成矿关系

Composition and deformation of Mian-Lue suture zone and their relationship with mineralization,Qinling orogenic belt

勉略构造带略阳 -勉县段组成复杂 ,包括勉略洋盆形成、不同时期演化、不同性质和环境的沉积岩系、蛇绿岩建造和岩浆侵入体。这些不同组成在造山过程中经强烈复杂的变形和变位 ,构成典型的非史密斯地层。依据时代、原岩建造、构造环境及变形变质作用 ,笔者将构造带划分为不同性质和类型的构造岩片系 ,并结合详细的构造解析 ,建立了勉略带构造变形序列。综合分析认为 ,勉略带经历了洋盆形成 (D- C1 )、俯冲闭合 (C1 - T1 )、碰撞造山 (T2 - T3)和陆内造山(T3- Q) 4个演化阶段 。

The Mian- L ue suture zone is composed of different types of ophiolites,with different naturesand a series ofsedimentary rocks formed atdifferentenvironments,and lots of exotic blocks,with tectonic emplacement in differentways. All of these rocks underwent deformation,displacementand metamorphism,thatis,these rocks are characterized by non- Smith Strata System. According to the time,protolith,tectonic- environment, metamorphism,deformation and the formation and evolution ofoceanicbasin,the Mian- L ue suture zone can be recognized different tectonic slices.Detail structural analysis suggested that these slices underwent superimposition of structures of different tectonic natures and levels in major and postorogenism. In the lightof above analysistogether with the regional feature of Qinling orogenic belt, the evolution processes of Mian- L ue suture can be recognized four stages:the initiation and spreading of the oceanic basin(D1 - C1 ) ,subduction and closure of the basin(C1 - T1 ) ,collision orogeny(T2 - T3) and postorogenic intercontinental stage(T3- Q) .The evolution processhas closely relationship with the regional mineralization.