柴北缘的大地构造演化及其地质事件群

Geological Events and Tectonic Evolution of the North Margin of the Qaidam Basin

柴达木盆地北缘及邻区包括六个二级构造单元:中南祁连地块(宗务隆天山期裂陷槽)、欧龙布鲁克微陆块、柴北缘祁连期结合带、柴达木地块、东昆仑晚天山-印支期结合带(东昆北岩浆弧)和西秦岭结合带。其中柴北缘及邻区的大地构造演化,经历了前寒武纪基底成生与演化、祁连期洋-陆转化、天山-印支期板内变形和中新生代陆相盆地演化-高原隆升等四个阶段。本文在论述各个演化阶段的沉积事件、岩浆活动、变质作用、构造形迹和成矿作用等地质事件群的基础上,对柴北缘的变质基底、全球大地构造对比和显生宙花岗岩等重大基础地质问题进行了讨论。

In the northern margin of Qaidam basin and its adjacent regions, there are 6 second-class tectonic units that can be divided： the Central-south Qilian massif （the early Hercynian Zongwulong aulacogen ）, the Oulongbruk micro-block, the Qilian collision belt in the northern Qaidam, the Qaidam block, the early Hercynian-Indosinian East Kunlun collision belt and the Indosinian West Qinling orogenic belt （Mesozoic and Cenozoic Gonghe-Xinghai fault basin）. And four evolution stages for these tectonic units have been recognized, that are the formation and evolution of the Precambrian basement, the pan-African to early Caledonian （Qilianian） ocean-continent transition, the early Hercynian （Tianshanian）-Indosinian intra-plate deformation, and the Mesozoic and Cenozoic continental basinplateau growth. Based on the geological events of sedimentation, magmatism, metamorphism, structural deformation and mineralization on every stages, some important geological subjects related to the northern margin of Qaidam basin are discussed in the paper, such as characters of the metamorphic basement, global tectonic comparison, the questions of Phanerozoic granites and so on.