滇东震旦系—寒武系界线层遗迹化石新发现及对比意义

NEW DISCOVERY OF TRACE FOSSILS FROM THE SINIAN-CAMBRIAN BOUNDARY BEDS IN EASTERN YUNNAN AND ITS SIGNIFICANCE FOR GLOBAL CORRELATION

滇东震旦系—寒武系界线层含有丰富多样的遗迹化石,经对27条剖面系统地采集化石和研究,共鉴定有遗迹属45个,遗迹种87个。其中新属2个,新种7个,已知属在本区首次发现的有31个,已知种在本区首次发现的有38个。根据不同遗迹属在界线层中出现的顺序和组合特征,将本区震旦系—寒武系界线层遗迹化石由老到新划分为4个遗迹化石组合带,并与国外相当层位的遗迹化石进行了对比,对地质意义作了初步地探讨。

Twenty-seven Sianian-Carnbrian boundary sections and abundant varied trace fossils in eastern Yunnan were systematicaly studied. Altogether 45 ichnogenera and 87 ichnospecies were discovered, collected and briefly identified. Among them, 2 ichnogenera and 7 ichnospecies are new ones and 33 undetermined.According to the variation of the trace fossil assemblages, 4 trace fossil sequences are divided in ascending order as follows:(1) Palaeopascichnus-Bilinichnus-Planolites;(2) Oldhamia-Phycodes-Sellaulichnus;(3) Rusophycus-Dimorpkichnus-Didymaulichnus;(4) Plagiogmus-Taphrhelminthopsis-Protopaleodictyon.The utilization of the sequences for defining the Sinian-Cambrian boundary and the significance for global correlation are discussed, and 1 new ichnogenus and 6 new ichnospecies are here described.