祁连山及其邻区大地构造基本特征──兼论早古生代海相火山岩的成因环境

BASIC CHARACTERISTICS OF TECTONICS IN THE QILIAN MOUNTAINS AND ITS NEIGHBOURINGS──ON GENETIC ENVIRONMENTS OF EARLY PALEOZOIC MARINE VOLCANICS

作者对中、南祁连的大地构造属性提出了新的见解，认为它们和柴达木地块具有同一前震旦纪基底，三者共同构成了柴达木板块。北祁连山的主体是介于中朝板块和柴达木板块间的早古生代缝合带。中朝板块的南缘有一个活动陆缘，由走廊弧后盆地和走廊南山北缘岛弧构成。从中寒武世以来，祁连山及其邻区构造演化经历了古大陆克拉通裂解，大洋克拉通演化阶段和新大陆克拉通演化阶段。现今的祁连山是这些构造演化共同作用的结果。早古生代海相火山岩的生成环境在南祁连为单一的裂谷环境。而在北祁连及走廊带，则不同时期具有不同的生成环境：（１）中寒武世为初始大洋裂谷环境，（２）早中奥陶世为具沟弧盆体系的政熟大洋，（３）晚奥陶世为残留洋盆，（４）志留纪为前陆盆地环境。

his paper put forward a new interpretation of tectonic nature of the central and the southern Qilian Mountains.The central and the southern Qilian Mountains as well as their common pre-Sinian basement all together constructed the aidam plate.Chief part of the Northern Qilian Mountains is an Early Paleozoic suture zone between the Sinokorean plate and the Qaidam plate.An active continental margin, which is located along the south edge of the Sinokorean plate,is composed of the Corridor back-basin and the north margin island are of the Corridor Nanshan Mountains.Since Middle Cambrian,the tectonic evolution of the Qilian Mountains and its neighbours underwent three stages as the followings:(1) break-up of ancient continental craton,(2) evolution of oceanic craton,and(3) development of new continental craton.Present Qilian Mountains resulted from three tectonic evolutions.Genetic environments of marine volcanics dating from Early Paleozoic are various. In the southern Qilian Mountains it belongs to an inland rift,but in the northern Qilian Mountains and Corridor belt it is various in different periods:(l) the embryonic oceanic rift during Middle Cambrian,(2) the mature ocean with a trough-arc-basin system during Early-Middle Ordovician,(3) the remainder oceanic basin during Late Ordovician,and(4) the foreland basin during Silurian.