摘要
华北地台北缘中晚元古代地壳运动分为燕辽旋回（１８～８．５亿ａ）、满家滩旋回（８．５～６亿ａ）。燕辽旋回为本区中、晚元古代坳拉谷发生发展消亡阶段，即地台第一盖层沉积地槽中晚元古代洋壳形成阶段。此阶段的白云鄂博亚旋回（１８～１４亿ａ）伸展裂陷作用为坳拉谷发生发展期，形成长城系；什那干亚旋回伸展拗陷作用为坳担谷发展萎缩期，形成蓟县系；汛河亚旋回收缩拗折作用为坳拉谷萎缩消亡期，沉积青白口系。地台北缘为被动大陆边缘。满家滩旋回地槽区向地台俯冲作用使地台第一次抬升隆起遭受剥蚀，仅在局部坳陷沉积震旦系、地台北部边缘为活动大陆边缘。
AbstractTwo tectonic cycles,Yanshan-Liaohe(1800-850Ma)and Manjiatan(850-600Ma),are distingushed from the crustal movements on the northern margin of North China platform. Yanshan-Liaohe cycle records the tectonic evolution, from initiation through development to consumption, of an aulacogen on the margion from the Middle to Late Proterozoic times.At the same tiem, the platform's first cover was deposited on the previous oceanic crust in the geosyncline.In view of its evolutional complexity,the cycle may be subdivided into three subcyles. Beiyunebo suboycle (1800-1400Ma) suggests initiation and development of the aulacogen which were marked by crustal extension and caused the deposition of the Changchen system. Shinagan snbcycle, recording a shift from growth to decline in the aulacogen,was accompanied by the sedimentation of the Jixian system. And Xunhe subcycle saw the Withering to consuling change in the aulacogen with contraction and down warping, leading to the Qingbeikou system. The northern margin of the platform represents passive continental margin Where the subduction of the geosyncline toward the platform during the Manjiatan cycle made it uplift for the first foe and undergo erosion with edments of the Sinian age in local downwarped regions. In contrast to the northern,the Southern margin belongs to active continental margin.
