西昆仑山北部早古生代构造－岩浆带的发现

1987年以来,先后做了4条横穿昆仑山的综合路线地质调查。它们是:中-巴公路沿线;新-藏公路沿线;于田县普鲁村-苏巴什-硫磺达坂路线;青海茫崖镇-祁曼塔格路线。在西昆仑山北部的调查区内,都有钙-碱性的深成岩体出露。通过对这些岩体系统地做U-Pb、Ar-Ar及Rb-Sr定年研究,发现它们具有早古生代年龄(384-480Ma),延伸上千公里,形成于活动大陆边缘或碰撞后的构造环境,常与属于蛇绿岩套的组分相伴生。这充分说明在青藏高原内部存在一条新发现的缝合带。

A DISCOVERY OF AN EARLY PALEOZOIC TECTONOMAGMATIC BELT IN THE NORTHERN PART OF WEST KUNLUN MOUNTAINS

Since 1987, totally four integrated geological investigation profiles across the West Kunlun Mountains were performed. They are: (1)Profile along the Sino-Pakistan highway (from Kashigar to Kunjirap Pass); (2)Profile along the XinjiangXizang highway .(from Yecheng to Shiquanhe); (3) Pulu Village, Yutian CountySubaxi-Liuhuang Pass profile, and(4) Mangnai Town, Qinghai-Qimantaga-Muzhtaga peak profile. In the investigation region, in the northern part of the West Kunlun Mountains calc-alkaline plutonic rocks are exposed. Systematical geochronological studies of the plutonic rocks have been done, in the paper 5 U-Pb dating on the zircons,3 Ar-Ar dating on the honblende and biotites and 5 Rb-Sr dating on the wholerocks and minerals from the plutons are reported. These results enabled us to find an early Paleozoic (384-480Ma) tectono-magmatic belt, extending for a thousandof kilometers. It was formed on an active continental margin or in a postcollisional tectonis envionment, and is accompanied with a complex belonging to ophiolite suit in Kudi, Subaxi and Oy ag area. It is a newly found and defined suture zonein the interior of the Qinghai-Xizang Plateau.