摘要
根据新的测年资料,原燕山地区青白口系下部的下马岭组被厘定为中元古界延展系(1 400～1 200 Ma)地层。对上部现在尚未获得精确年龄的长龙山组和景儿峪组,本文通过它们与下伏地层界线性质的研究,以及它们与辽南和华南等新元古代典型沉积盆地不同发展阶段沉积特征的比较,认为它们并不是象过去K-Ar年龄所指示的那样属于青白口纪(或拉伸纪)的晚期地层,而可能是在全球罗地尼亚超大陆开始进一步裂解背景下形成的南华纪(或成冰纪)早期沉积,年龄可能在780 Ma和660 Ma之间。因此,燕山地区的原"青白口系"可能都不是真正青白口纪(1000～800 Ma)的地层,燕山地区的原"青白口系"可能要被全部解体。
On the basis of the new datings, the Xiamaling Formation of the lower Qingbaokou System in Yanshan range has been identified as the deposits of the early Ectasian System（1 400 - 1 200 Ma）, the middle Mesoprotero-zoic. As for the Changlongshan and Jingeryu Formations of the upper Qingbaikou that they are without more pre-cise dating up to now, through the research for the nature of the boundary between them and underlying strata, and the comparison with depositional characteristics of different stages of tectonic development in a number of representative Neoproterozoic basin in Liangdong Peninsula and south China, this paper tend that they are not the upper Qingbaikou （Tonian） as shown by previous K-Ar ages and are the deposits in the early Nanhua period （or early Cryogenian） under the background of that the Rodinia Supercontinent was further broken-up.Their age is be-tween 780 Ma and 660 Ma possibly. That is to say, the standard Qingbaikouan System in yanshan range is not the strata of the Qingbakouan Period and all the Qingbaikouan System in yanshan range will be disintegrated possi-bly.
出处
《地质调查与研究》
2012年第2期81-95,共15页
Geological Survey and Research
基金
全国地层委员会项目:中国主要断代地层建阶研究
中国石油化工股份有限公司前瞻性项目(YPH08086)
中国地质大学(武汉)生物地质与环境地质国家重点实验室主任基金项目
关键词
解体
青白口系
新元古界
燕山
华北
disintegration
Qingbaikouan System
Neoproterozoic
Yanshan range
North China
