内蒙古林西地区上二叠统林西组叶肢介化石的发现及意义

The discovery of conchostracan fossils in the Upper Permian Linxi Formation of Linxi area,Inner Mongolia,and its geological significance

前人对林西县上二叠统林西组和扎鲁特旗陶海营子组进行过长期研究,发现较多淡水双壳类和植物化石,而叶肢介化石仅在陶海营子组有所发现。本次研究在内蒙古林西县官地剖面林西组的中上部首次发现叶肢介化石,经初步鉴定为林西黄河叶肢介(新种)等3个属种。叶肢介化石的发现为林西组时代的进一步确定、地层对比和古地理重建提供了可靠的化石依据,具有重要的地层学和古地理古构造学意义。

Previous researches on the Upper Permian Linxi Formation in Linxi County and Taohaiyingzi Formation in Jalaid Banner show that the main fossils are freshwater bivalves and plant fossils.Except for Taohaiyingzi Formation,conchostracan fossils had never been discovered in this area.In this study,the conchostracan fossils were discovered firstly in the upper part of the Linxi Formation in Guandi section of eastern Linxi County,Inner Mongolia,which are preliminarily identified as Huanghestheria linxiensis Niu（sp.nov）.,Cyclotunguzites cf.gazimuri Novojilov,and Sphaerorthothemos cf.cellulatus（Lutkevich） respectively.Therefore,the conchostracan fossils discovery in Linxi Formation provides the reliable fossil evidence for the determination of the age of Linxi Formation as well as for stratigraphic correlation and palaeogeographic reconstruction.This achievement has important stratigraphic and palaeogeographicy tectonic significance.