摘要
柴达木盆地北缘的欧龙布鲁克微板块发育了一套元古宙碎屑岩与碳酸盐岩地层,以往被称为全吉群,不整合覆于变质结晶基底之上,伏于寒武系之下。这套地层在全吉山、石灰沟及欧龙布鲁克山等地区的多个剖面出露良好,但在石灰沟、欧龙布鲁克地区均有不同程度的缺失,而全吉山地区保存的沉积序列相对最为完整。前人对于全吉群的划分、对比及其沉积时代长期存在不同认识。在《中国地层表(2014)》中,全吉群包括麻黄沟组至皱节山组,其中麻黄沟组、枯柏木组和石英梁组属南华系,而红藻山组、黑土坡组、红铁沟组和皱节山组属震旦系。近年来,生物地层学、同位素年代地层学方面的证据表明,红藻山组及其下伏地层沉积于古元古代晚期到中元古代早期(距今约17~16亿年),代表了该时期的一套裂谷盆地沉积物,而上覆黑土坡组、红铁沟组和皱节山组则沉积于新元古代中晚期(晚于距今7.5亿年)。考虑到这两套地层之间存在着8~9亿年的沉积间断,本文支持将全吉群进行重新定义,厘定后的全吉群仅包含麻黄沟组、枯柏木组、石英梁组和红藻山组,上覆新元古代地层(黑土坡组、红铁沟组和皱节山组)则不做群一级别的划分。
The Proterozoic strata developed in the Olongbuluke terrane,the northern Qaidam Basin,Northwest China are composed of siliciclastic and carbonate rocks that unconformably sit on the Paleoproterozoic metamorphic basement and unconformably underlie the Cambrian rocks.The Proterozoic strata crop out well in the Quanjishan,Shihuigou,and Olongbuluke areas,and are most complete in the Quanjishan section,with an increasingly missing of sediments eastwards.There have been different stratigraphic schemes for the subdivision and correlation of the Proterozoic successions,as well as different opinions about their depositional age in the Olongbuluke terrane.According to the Stratigraphic Chart of China(2014),the Quanji Group consists of the Mahuanggou,Kubaimu,Shiyingliang,Hongzaoshan,Heitupo,Hongtiegou,and Zhoujieshan formations;the Mahuanggou,Kubaimu,and Shiyingliang formations have been regarded as the Nanhua System(roughly equals to the Cryogenian System),whereas the Hongzaoshan,Heitupo,Hongtiegou,and Zhoujieshan formations have been assigned to the Sinian System(equals to the Ediacaran System).However,recent advances in biostratigraphy and radiometric geochronology indicate that the Hongzaoshan Formation and its underlying strata were deposited at~1.7-1.6 Ga,representing a set of rift basin sediments from late Paleoproterozoic to early Mesoproterozoic,whereas the overlying Heitupo,Hongtiegou,and Zhoujieshan formations may belong to middle to late Neoproterozoic.Considering that there is a sedimentary hiatus of 800-900 Myr between the Hongzaoshan and Heitupo formations,we propose that the Quanji Group shall be redefined to contain only the late Paleoproterozoic to early Mesoproterozoic Mahuanggou,Kubaimu,Shiyingliang,and Hongzaoshan formations,and the overlying Neoproterozoic strata,including the Heitupo,Hongtiegou,and Zhoujieshan formations,shall temporarily not be included in any group-level lithostratigraphic units.
作者
吴承羲
孙云鹏
欧阳晴
李光金
周传明
庞科
WU Cheng-Xi;SUN Yun-Peng;OUYANG Qing;LI Guang-Jin;ZHOU Chuan-Ming;PANG Ke(State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academyof Sciences,Nanjing210008;University of Chinese Academy of Sciences,Beijing 100049;University of Chinese Academyof Sciences Nanjing,Nanjing 211135)
出处
《地层学杂志》
CSCD
北大核心
2024年第1期1-16,共16页
Journal of Stratigraphy
基金
第二次青藏科考研究国家专项(2019QZKK0706)
国家自然科学基金(42272005、41921002)
国家重点研发计划(2022YFF0802700)
现代古生物学和地层学国家重点实验室(20201102、213108)
中国科学院青年创新促进会(2021307)
中国博士后科学基金(2021M693243)共同资助。
