中天山早泥盆世陆弧：来自花岗质糜棱岩地球化学及SHRIMP-U/Pb定年的证据

Earlier Devonian active continental arc in Central Tianshan:evidence of geochemical analyses and Zircon SHRIMP dating on mylonitized granitic rock.

中天山巴伦台以北地区出露一套糜棱岩化的中—酸性侵入岩,元素地球化学特点表明其属于火山弧环境；锆石SHRIMP U/Pb法测试结果揭示其侵位年龄在405～416Ma间,属早泥盆世。这一研究结果显示,早在晚志留世晚期,南天山洋已开始向北俯冲,并在中天山地块南缘形成火山弧环境。至早泥盆世晚期,塔里木陆块与中天山火山弧发生碰撞。

Mylonitized dioritic-granitic plutons occurred in north of Baluntai area, central Tianshan, Northwest China. Element geochemical data reveal that the dioritic-granitic plutons were generated at active continental arc environment like today＇s Chile ; zircon U/Pb SHRIMP dating and CL imaging indicat that the active continental volcano arc developed at 405 -416 Ma. These data demonstrat that the paleo-south Tianshan ocean crust started northward subducting under the central Tianshan block at earlier Devonian, resulting in a continental arc upon the overriding plate. The following collision between the central Tianshan block and the Tarim block might begin at later of Earlier Devonian.