青海省都兰县江各早—中三叠世火山岩岩石学特征及构造环境

Petrological Characteristics and Tectonic Environment of Early-Middle Triassic Volcanic Rocks in Jiangge of Dulan County in Qinghai Province

都兰县沟里公社江各一带零星分布的火山岩处于柴达木南缘,火山岩受后期构造运动的破坏和侵入体的侵噬,呈支离破碎的断块残留在侵入体内,空间展布上受断裂构造控制,在野外地质调查的基础上,结合室内岩石学、地球化学、同位素年龄研究,该火山岩形成时代为早-中三叠世,为消减带俯冲碰撞的岛弧环境。

Scattered volcanic rocks distributed along Jiangge in Gouli community of Dulan county.They are located in the southern margin of Qaidam basin.Due to destroy and corrosion by the intrusive bodies of tectonic movement in late period,volcanic rocks show as fragmented fault blocks in the intrusive bodies, which was controlled apparently by the faults on space distribution.On the basis of geological survey, combining with the study on petrology,geochemistry,isotope age,it is regarded that volcanic rocks were formed in early middle Triassic period.It is island arc environment formed by subduction belts collision.