四川峨眉麦地坪剖面震旦系—寒武系界线的新认识及有关化石群的记述

研究剖面位于峨眉山东坡,距峨眉县城约14公里。峨眉山区在大地构造上处于川滇南北向构造带的东侧——峨眉山块断带。震旦系-寒武系出露在蛾眉山背斜两翼,构造简单,地层连续,化石丰富。此剖面先后经过多人研究。

THE NEW KNOWLEDGE OF THE FOSSIL ASSEMBLAGES FROM MAIDIPING SECTION,EMEI COUNTY,SICHUAN WITH REFERENCE TO THE SINIAN-CAMBRIAN BOUNDARY

In accordance with the fossil assemblages from the fossiliferous horizons newly encountered of the section,which is selected as one of the five candidate sections in China by the Working Group on the Precambrian-Cambrian boundary of IGCP in 1979,the Precambrian-Cambrian boundary is discussed herein.At present,the bounary is drawn some 16m lower than that determined at that time.In this paper,a total of 14 forms (including 4 new genera and 7 new species) are described from the 34th bed of this section.Of these fossils,the Quadrosiphogonuchites is probably an ancestral form of Colularid,the Arthrochites is a distinct form belonging possibly to Arthropoda,and especially the conodonts undoubtedly show that the diversification of them had taken place much earlier than that supposed previously.The microstructures of some fossils are studied under microscope.These fossil assemblages are evidently of rather important significance on palaeontology.