摘要
中新元古界白云鄂博群发育于华北板块北缘,是中新元古代板块内部伸展-拉张背景下沉积的产物。在内蒙古白乃庙地区白云鄂博群哈拉霍圪特组中首次发现一套软沉积变形构造,发育在该组下部的结晶灰岩中,主要表现有自碎屑角砾岩、软沉积褶皱、层内阶梯状正断层、液化方解石脉等,软沉积变形特征表明其成因为震积岩。通过与相邻地区同时代的腮林忽洞群进行对比,两者具备相似的软沉积变形特征,成因与时代大体一致。白云鄂博群震积岩的发现表明,中新元古代期间华北板块北缘处于一个快速强烈的拉张-裂解构造背景,为研究华北板块北缘中新元古代的构造演化提供了新的资料。
The Middle-Upper Proterozoic Bayan Obo Group is located at the northern margin of the North China Craton,and was deposited under intra-plate tectonic setting of extension in Middle-Late Proterozoic.From the Halahuogete Formation of Bayan Obo Group in the Bainaimiao area of Inner Mongolia,the authors discovered a set of structures resulted from soft-sediment deformation for the first time.They occur within the crystalline limestone at the lower section of this group,and include remobilisation breccias,synsedimentary folds,fault-grading,molar tooth and so on.These characteristics demonstrate they belong to the seismites.According to further comparisons between the Bayan Obo Group and the contemporary Sailinhudong Group nearby,we found they exhibit similar features of soft-sediment deformation as well as the same age of formation.This discovery of the seismites from Bayan Obo Group indicates the northern margin of the North China Craton was undergoing a rapid and intense extension and divergence in Middle-Late Proterozoic,which provides fundamental observations for further studies on tectonic evolution of the North China Craton.
出处
《现代地质》
CAS
CSCD
北大核心
2011年第3期503-509,共7页
Geoscience
基金
国土资源部中国地质调查局"华北地区基础地质及数据更新项目"(1212010510506
1212010811001)
内蒙古自治区地质勘查基金项目(KD78)
关键词
白云鄂博群
软沉积变形
震积岩
内蒙古
Bayan Obo Group
soft-sediment deformation
seismite
Inner Mongolia
