地质学报2017，Vol.91Issue(8)：1860-1877,18.
京西雾迷山组第4段强迫型海退过程中的层序旋回特征及其构造古地理意义
Features of the Sequence Cycle in the Forced Regression Process of the Fourth Member of Wumishan Formation, Western Beijing and Its Tectonic Paleogeographic Significance
摘要
Abstract
The sequence cycle of the transgressive stage of lower to middle Wumishan Formation in the YanshanLiaoning area is characterized by symmetrical facies sequences and fabrics,but no detailed study has been paid on the sequence cycle of the regressive process of the upper Wumishan Formation.For this purpose,a systematic research about sedimentary microfacies,sedimentary facies sequences,sequences stratigraphy and chemical stratigraphy of the fourth member of the Wumishan Formation at Zhuanghuwa section,Yongding river valley,western Beijing,was carried out to restore sedimentary facies and classify parasequence type.Carbon and oxygon isotopic compositions and relevant data analyses were also performed to verify the evolution process of the ancient environment.Nine lithofacies have been identified in the Zhuanghuwa section,indicating different depths of water,topography,and biological conditions,which are also confirmed by corresponding δ13C and δ18O values.Generally,with the paleotemperature T increasing,the values of δ18O and paleosalinity Z decrease,reflecting sea level rise;conversely,reflecting sea level drop.Our research shows the sequences cycle of the regressive process is characterized by asymmetrical facies sequences and fabrics,its parasequence fabrics becomes gradually simple from supratidal zone to subtidal zone,and the minisequence of superimposed patterns evolves from 1∶ 4 to 1∶2.Therefore,facies sequences and fabrics of the fourth member of Wumishan Formation is distinctively different from the typical "Sequence Cycle of Wumishan Formation",and this is probably related to the tectonic evolution from aulacogen to epeiric sea at the north margin of North China Platform in the Mesoproterozoic.关键词
北京西部/雾迷山组第4段(闪坡岭亚组)/强迫型海退/层序旋回/碳氧同位素/构造演化转折Key words
Western Beijing/the fourth member of Wumishan Formation(shanpoling subformation)/forced regression/sequence cycle/C and O isotopes/tectonic transition引用本文复制引用
陆晨明,刘本培,蒋子堃,张在明,叶群芳..京西雾迷山组第4段强迫型海退过程中的层序旋回特征及其构造古地理意义[J].地质学报,2017,91(8):1860-1877,18.基金项目
本文为中国地质科学院基本科研业务费(编号:YWF201608和YWF201609)和国家自然科学基金青年基金项目(编号:41402004)资助的成果. （编号:YWF201608和YWF201609）
