简述辽宁中元古界长城系—新元古界青白口系形成与演化

ANALYSIS ON THE FORMATION AND EVOLUTION OF MESOPROTEROZOIC CHANGCHENG SYSTEM TO NEOPROTEROZOIC QINGBAIKOU SYSTEM IN LIAONING

辽宁地区广泛分布中元古代地层,自中元古代长城纪起,华北陆块在结晶基底形成之后,进入了稳定的盖层发展阶段.从岩相古地理特点、构造演化方面探讨了辽宁地区中元古代长城系—新元古代青白口系的形成与演化.其中,长城系为晋宁旋回的第一个盖层,发生了两次海侵;蓟县系—待建系为晋宁旋回的第二盖层,组成了海进—海退—海进序列;青白口纪时期,受郯庐断裂影响,古地理格局发生了巨大变化,辽东半岛形成了新的盆地,辽西、辽北继承了前期构造格局,构成了第三盖层.

The Mesoproterozoic strata are widely distributed in Liaoning region.Since the Mesoproterozoic Changcheng Period,the North China Craton has experienced a stably developed cover stage after the formation of crystalline basement.The formation and evolution of Mesoproterozoic Changcheng System-Neoproterozoic Qingbaikou System in the region are discussed on lithofacies paleogeography and tectonic development.The Changcheng system is the first cover in Jinning cycle,during which two transgressions happened.The Jixian System is the second cover in Jinning cycle,in which the transgressive-regressive-transgressive sequence is composed.During Qingbaikou Period,the paleogeographic pattern changed immensely by Tanlu fault,when the Liaodong Peninsula formed a new basin while the previous tectonics are inherited in western and northern Liaoning to form the third cover.