华北克拉通南部熊耳盆地晚前寒武纪年代地层格架和演化

Late Precambrian chronostratigraphic framework and tectonic evolution of the Xiong’er basin in southern North China Craton

熊耳盆地发育华北克拉通最齐全的晚前寒武纪地层,是认识华北克拉通晚前寒武纪沉积和构造演化历史的理想地区。依据收集和自测的38个碎屑岩和23个岩浆岩样品的锆石年代学数据,结合岩相区域对比、沉积古地理格局继承关系等,细化年代地层格架和分析盆地构造属性,重塑熊耳盆地晚前寒武纪构造演化历史及沉积古地理格局。重新厘定的晚前寒武纪年代地层格架将熊耳盆地演化划分为六个阶段:早长城世裂陷、晚长城世断陷、蓟县纪坳陷、待建纪早期坳陷、青白口纪坳陷及晚震旦世冰期坳陷,以及早长城世末期、待建纪中晚期和南华纪—早震旦世三期重要的沉积间断。熊耳盆地存在晚长城世和青白口纪两期碰撞型—伸展型的盆地属性转换,支持北秦岭地体与华北克拉通多期拼贴—裂解的演化模式。中元古代早长城世—待建纪早期的火山-沉积岩系及1.64~1.47 Ga非造山岩浆事件是Columbia超大陆裂解的地质响应,青白口纪早期碰撞型沉积岩系和晚期伸展型火山-沉积岩系分别是Rodinia超大陆汇聚和裂解的地质响应。

The Xiong’er basin,with best preserved late Precambrian stratain the North China Craton,is an ideal site for reevaluating the sedimentary and tectonic evolution history of this period.Based on the collected and newly analyzed zircon chronology data of 38 clastic and 23 magmatic rocks,regional comparison of lithofacies and inheritance of sedimentary palaeogeographic patterns,the Late Precambrian chronostratigraphic framework,tectonic setting,evolution history as well as sedimentary paleogeography pattern are systematically studied.The readjusted chronostratigraphic framework divides the Late Precambrian evolution of the Xiong’er Basin into 6 basin stages,including aulacogen in the Early Changcheng Epoch,fault basin in the Late Changcheng Epoch,depression basin in the Jixian Period,depression basin in the early phase of the Unnamed period(Ectasian Period),depression basin in the Qingbaikou Period,as well as glacial depression basin in the Late Sinian Epoch,with three major sedimentary discontinuities in the end of Early Changcheng Epoch,middle-late phase of the Unnamed period,and Nanhua Period to Early Sinian Epoch.The collisional to extensional transition of tectonic setting in the Late Changcheng Epoch and Qingbaikou Period support the evolution model of multi-stage convergence and breakup between the North Qinling Terrane and the North China Craton.The volcanic-sedimentary rock series in the Early Changcheng Epoch to the early phase of the Unnamed period(Ectasian period)of the Mesoproterozoic Era and the 1.64~1.47 Ga anorogenic magmatic events are the geological responses to the breakup of the Columbia supercontinent.The sedimentary rock series of collisional setting and volcanic-sedimentary rock series of extensional setting in the early phase of the Qingbaikou Period are the geological response to convergence and breakup of the Rodinia supercontinent respectively.