摘要
分布于华北地台南缘豫西汝阳地区的中上元古界汝阳群、洛峪群为一套河流相—滨海相—浅海陆棚相—局限台地相的碎屑岩—碳酸盐岩沉积建造。在该区１∶５００００区域地质调查过程中，作者运用层序地层学的基本原理，探讨了该套地层的层序地层特征。在该地层中识别出了２个Ⅰ型不整合界面，９个Ⅱ型不整合界面；划分出了１个Ⅰ类层序，９个Ⅱ类层序，并将中上元古界划归一个超层序，初步建立了该区中上元古界的岩石地层格架。中上元古界岩石地层格架的顶、底界面均为Ⅰ型不整合界面，与年代地层界面相一致。格架内部各个层序之间的界面均为Ⅱ型不整合界面。只有少数Ⅱ型界面位于岩石地层单位分“组”界线附近或与其一致，大多数Ⅱ型界面位于“组”内。层序地层的划分与岩石地层的划分具有明显的不一致性。本文综述了研究区内中上元古界超层序、内部各类层序的顶底界面特征。
On the south border of North China platform,the Middle to Upper Proterozoic Ruyang Group and Luoyu Group in Ruyang area,the West of Henan Province is a suite of the clastic rock to carbonatite formations having the fluvial facies,littoral facies,neritic shelf facies,restricted platform facies.In the course of the regional geological survey on scale of 1∶50000,the principle of sequence stratigraphy is used by the author,the characteristics of sequence stratigraphy of Ruyang and Luoyu Groups have been approached.In this suite strata,two Ⅰ type sequence unconformable boundaries,nine Ⅱ type sequence unconformable boundaries have been distinguished.One Ⅰ type sequence,nine Ⅱ type sequences have been classified,and incorporated the Ruyang Group and Luoyu Group into a super sequence.The Middle Upper Proterozoic lithostratigraphic framework in this area is first established in this paper. The top boundary and the bottom boundary of the lithostratigraphic framework are all Ⅰ type sequence unconformable boundaries,they are in accord with the chronostratigraphic boundaries.The boundaries of every sequence in the lithostratigraphic framework are all Ⅱ type sequence unconformable boundaries.Only a few Ⅱ type boundaries are situated on the nearness of the boundaries of lithostratigraphic unit “Formation”or in accord with it.The major Ⅱ type boundaries of sequence situated in the Formations.The classifications of sequence stratigraphy are distinctly out of accord with the lithostratigraphic classifications.The characteristics of the top bottom boundaries of different sequences,sedimentation and lateral changing of the Middle to Upper Proterozoic super sequence are summarized in this paper.
出处
《河南地质》
1997年第1期29-35,共7页
Henan Geology
关键词
层序地层
岩石地层格架
上元古界
中元古界
Ruyang area in the West of Henan Province,Middle to Upper Proterozoic erathem,sequence stratigraphy,lithostratigraphic framework
