摘要
川西高原是否存在中三叠统拉丁阶?一直是人们所关心的问题。朱占祥等对拉丁阶的一些零星发现作过初步报导。松潘地区安壁村拉丁期瓣鳃类Daonella lommeli和牙形石 Neogondolella excelsa等也作了分析。殷鸿福也讨论了中国的拉丁阶问题。 在松潘以北、岷江以西8—12km范围内,曾做过初期阶段的地质填图,西部香腊台—花山—黄胜关—则哈一带的石灰岩和砂板岩,被定为泥盆系、石炭系和下二叠统。
The problem of whether the Mid-Triassic Ladinian strata are present in the western Sichuan plateau has been attracting much attention for a long time.On the basis of recent geological data, we reexamine the Triassic Zagashan Formation in the Songpan area, western Sichuan, and analyze geological ages and geographic distribution of bivalves (3 genera and 22 species), conodonts(7 genera and 9 species) and crinoids (3 genera and 3 species) obtained from the formation.It is proved that the Zagashan Formation is Middle Triassic in age, and that the Songpan area is one of the richest occurrences of the Ladinian fossils in southern China.This provides further evidence for Triassic correlation, palaeogeographic analysis and Indosinian tectonic evolution in the Qinghai-Xizang plateau.Some problems previous and present, concerning the stratigraphy of the Songpan area have also been discussed in the paper.
出处
《地层学杂志》
CSCD
北大核心
1991年第1期42-47,T001,共7页
Journal of Stratigraphy
