摘要
本文把华南法门阶上部和杜内阶分为４个层序，自下而上依次命名为ＳＱ０、ＳＱ１、ＳＱ２和ＳＱ３。其中ＳＱ０属斯图年阶（Ｓｔｒｕｎｉａｎ）（泥盆系最顶部），其余３个层序归杜内阶。这４个层序可以与欧美等地同期的层序进行对比，表明当时的海平面升降变化及其由此而产生的沉积层序具有全球的一致性。层序地层学、生物地层学和事件地层学综合研究表明，华南浅海相区与Ｓｉｐｈｏｎｏｄｅｌａｐｒａｅｓｕｌｃａｔａ－Ｓ．ｓｕｌｃａｔａ界线一致的泥盆－石炭系界线不仅高于Ｃｙｓｔｏｐｈｒｅｎｔｉｓ带顶界，而且还应高于引起Ｃｙｓｔｏｐｈｒｅｎｔｉｓ绝灭的海退事件层的顶界。因此建议以Ｃｙｓｔｏｐｈｒｅｎｔｉｓ－Ｐｓｅｕｄｏｕｒａｌｉｎａ间隔带中最明显的一个海进面，即ＳＱ１的海进体系域的底界作为华南浅海相区泥盆－石炭系界线。这条界线与泥盆－石炭纪之交海退事件层的顶界正好一致。
In South China four depositional sequences are recognized in the upper part of Upper Devonian and Tournaisian. They are named SQ1, SQ2, SQ3 and SQ4 in ascending order. SQ1 is Strunian (uppermost Devonian), and the other three Tournaisian in age. These four depositional sequences are very well correlated with these four sequences recognized in Europe, North American and other areas. This suggests that these sequences are cynchronous deposits resulting from eustatic sea Level changes. The study of sequence stratigraphy, biostratigraphy and event stratigraphy indicates that in neritic facies areas of South China, the Devonian Carboniferous Boundary, matching the boundary between Siphonodella praesulcata Zone and S . sulcata Zone in pelagic facies areas, is not only higher than the top of the Cystophrentis Zone, but also higher than the top of the Devonian Carhoniferous boundary event. In neritic facies areas, therefore, the Devonian Carboniferous Boundary is marked by the most distinct transgressive surface within the Cystophrentis Pseudouralina Interval Zone, i.e. the base of the TST of the SQ1. This boundary just coincides with the top surface of the event beds resulting from the eustatic fall of sea level, and approximately corresponds to the basal part of Pseudouralina Assemblage Zone.
基金
国家基础性研究重大关键项目
国家教委留学回国人员科研资助费资助
关键词
层序地层学
上泥盆统
下石炭统
华南地区
sequence stratigraphy Upper Devonian Lower Carboniferous South China boundary
