东天山中段晚古生代剪切带叠加特征及构造控矿作用

Superposition of Late Paleozoic shear zones and its structural ore-controlling function in the central of Eastern Tianshan

东天山东中段发育具明显叠加特征的晚古生代剪切构造。采用区域构造分析和构造解析方法,在土墩-山口站地区厘定出二类(期)韧性剪切带。早期为一种面状韧性剪切带,形成于近南北向的分层剪切作用(D1),并因随后的挤压变形(D2)而陡立;晚期为一种线性(带状)剪切带,主要表现为近东西向的走滑性质(D3)。第二类(期)剪切多同向叠加于陡立的第一类(期)剪切之上,且二类(期)构造均伴有同构造的岩浆活动,是晚古生代的俯冲碰撞造山事件的构造响应,并记录了不同变形机制下的构造变动和演化过程。区域叠加剪切构造的厘定和确认有助于完善和深化东天山中段的晚古生代构造演化及金多金属成矿机制的理解和认识。

The recent field investigation support development of the very conspicuous superposition of Late paleozoic ductile shear zones in the central of Eastern Tianshan.And two types(generation)of ductile shear structures are distinguished by detailed regional structural analysis and structural examination in the Tudun-Shankouzhan areas.The early one is a plane(laminar)ductile shear zone originated during the intensive deformation period of nearly S-N delamination shearing(D1),and steepened due to the subsequent compression deformation(D2).The late one is a narrow(corridor)ductile shear zone characterized by nearly E-W strike slip(D3).Mostly,the latter shear zones parallelly overprint the steepened early ones.And the widespread intrusion and emplacement of syn-kinematic granitoid bodies along the two types of ductile structures indicates that they are related to the late Paleozoic subduction-collision orogeny and record the evolution of the different deformation regimes in space and time.This work can be useful to understand the complex structural/tectonic evolution and Gold polymetallic metallogenic mechanism of the central of East Tianshan.