内蒙造山带南部古板块构造演化

对内蒙造山带南部构造岩石组合、构造序列和部分岩石的同位素年龄研究表明，华北板块北缘在中元古代由大陆裂谷发展成被动陆缘，晚元古代开始转为活动陆缘，延续至早古生代转为俯冲－左旋走滑。随着温都尔庙蛇绿岩的定位和俯冲带北移、贺根山蛇绿岩的定位，内蒙造山带南部分别经历了两次均衡抬升－裂陷。海西末期华北－西伯利亚两大板块已缝合，进入超碰撞阶段，区内花岗岩大量侵位并形成了一系列推覆构造。

PALAEOPLATE EVOLUTION IN THE SOUTHERN PART OF THE INNER MONGOLIAN OROGENIC BELT

The palaeoplate evolution in the southern part of the Inner Mongolianorogenic belt can be tentalively concluded as follows on the basis of studies ofthe petrotectonic assemblages, structural sequence, and isotope dates of someimportant rocks in the past five years. The northern margin of the North Chinaplate probably developed from continental rift to passive continental margin inthe Middle Proterozoic. It began to transform into the active continental marginin the Late Proterozoic and by the Early Paleozoic, it began to be subducted andslipped sinistrally. The southern area of the Inner Mongolian orogenic beltunder-went isostatic uplift and faulting twice, following the emplacement of the OndurSum ophiolite. The North China and Siberian plates were sutured in the terminalHercynian and then the evolution of the orogenic belt entered a stage of ultraco-Ilision, when a vast amount of granite intruded and a series of nappe structureswere formed.