东昆仑—柴达木地区泥盆系划分对比

DIVISION AND CORRELATION OF THE DEVONIAN SYSTEM IN THE EAST KUNLUN-QAIDAM AREA THE EAST KUNLUN-QAIDAM AREA

东昆仑—柴达木地区泥盆系较为发育,均表现为陆相碎屑岩和火山岩沉积。前人将该地区泥盆系笼统地划归晚泥盆世牦牛山组,但其空间分布情况不详,划分与对比仍存争议。本文结合近些年在该地区开展的1/5万、1/25万区域地质调查和相关的科研成果等资料,重新厘定了东昆仑—柴达木地区泥盆系,将牦牛山组限于柴达木盆地北缘地区,代表中—晚泥盆世陆相碎屑岩-火山岩沉积;重新启用契盖苏组,代表东昆北地区早泥盆世陆相碎屑岩-火山岩沉积;新建雪水河组代表万保沟地区早泥盆世陆相碎屑岩-火山碎屑岩沉积。

The Devonian System in the East Kunlun-Qaidam area is relatively well-represented by the terrestrial clastic deposits and volcanic rocks.Previously,these rocks were all assigned to the Maoniushan Formation of Late Devonian,but their spatial distribution is poorly known,and their division and correlation remain controversial.In this paper,we propose a new Devonian stratigraphic and correlation scheme of the area on the basis of the latest 1/50,000 and 1/250,000 scale regional geological surveys and related scientific researches.The Maoniushan Formation is redefined to be restricted to the northern margin of the Qaidam Basin and represent Middle-Late Devonian terrestrial clastic-volcanic deposits.The formally abandoned Qigaisu Formation is valid and represent the Early Devonian terrestrial clastic-volcanic strata in the eastern Kunbei area,and a new unit Xueshuihe Formation is proposed to represent the Early Devonian terrestrial clastic-volcanic rocks in the Wanbaogou area.