中国西藏南部珠穆朗玛峯地区的岩浆岩、变质岩和混合岩

前言珠穆朗玛峰地区系指西藏雅鲁藏布江以南,亚东以西,吉隆以东的我国境内广大地区。在解放以后,曾有多次科学考察,尤其在1966年至1968年,由中国科学院组织西藏科学考察队,对这一地区进行了大规模的多学科考察。

MAGMATIC, METAMORPHIC AND MIGMATIC ROCKS OF THE MOUNT JOLMO LUNGMA REGION IN SOUTHERN TIBET, CHINA

There were three magmatic episodes in the described territory. Their sequence and distribution were discussed. There are various kinds of skarns and andalusite hornfels. The migmatites reveal potash- and sodium-metasomatism. It is suggested that the fluid of alkali-silicates was originated from the deep crust, and the alkali material themselves were primarily products of the deep rocks.Based upon their occurrence, stratigraphical position, grade of metamorphism, and index minerals, the Jolmo Lungma Group can be classified into the muscovite-, two-mica-, almandine-, staurolite- and kyanite- zones. They all represent a medium grade of metamorphism, being a progressive metamorphic sequence of the almandine-amphi-bolite-facies.The territory studied has two episodes of regional metamorphism, viz: 640-660×106 yrs of Precambrian, and 10-20× 106 yrs of Miocene. Products of the first episode of metamorphism were modified by the second episode of metamorphism, with expressions of regressive metamorphism.