罗平生物群化石在云南丘北地区的发现及其意义

THE DISCOVERY AND SIGNIFICANCE OF LUOPING BIOTA FOSSIL IN QIUBEI AREA,YUNNAN

罗平生物群是三叠纪海洋生态系统生物辐射的典型代表,是一个以海生爬行类、鱼类、节肢动物、棘皮动物、软体动物、腕足动物和植物等海洋古生物群落,广泛分布于滇东及滇东南中三叠统派尔逊(Pelsonian)亚阶关岭组二段中。本文报道了云南丘北地区斗母村附近斗母坡采石场发现的具有罗平生物群化石的新产地,主要以海百合类、双壳类、腕足类和腹足类为主,及少量海生爬行类、龙鱼类、辐鳍鱼类、牙形类和植物等化石;描述了化石产地的基本生物组合面貌、产出层位特征和保存状态。根据实测的仙人井剖面,化石层出露于关岭组二段上部薄-中层状泥晶灰岩中,与罗平和泸西地区相当;化石层厚度薄,保存段厚度约3m。综合比较罗平和泸西地区化石赋存岩性特征和生物组合面貌,认为丘北发现的化石类型可纳入罗平生物群范畴。填补了丘北地区中三叠世无脊椎动物化石报道的空白,扩大了罗平生物群化石库的分布范围,为对比研究罗平生物群的古地理分布、生物组合、特异埋藏等方面提供了新的材料。

Luoping biota is the typical representative of T marine ecological system biological radiation,which is a marine palaeontological community of reptile,fishes,arthropod,echinoderms,mollusk,brachiopod,flora,etc,distributed widely in Middle T Pelsonian Subepoch Guanling Formation Member 2 in E and SE Yunnan.In this paper,we report the new location of Louping Biota fossil,i.e.Doumupo quarry near Doumu Village in Qiubei area,Yunnan,with mainly crinoids,bivalves,brachiopod and gastropods,and a few marine reptiles,saurichthys,actinoperygiansconodonts and plants,etc.The basic feature of fossil assemblage,preservation horizon and status are interpreted.According to the measured Xianrenjing section,th fossils are outcropped in thin-to middle-bedded micrites of Member 2 upper part of guanling formation,in correspondence with those in Luoping and Luxi region,the fossil bed is thin,about 3m only.We think the fossil type discovery of Qiubei can be put into Luoping biota category,remedying the blank of Qiubei area without Middle T vertebrate,expanding the distribution range of Luoping biota fossils,providing new information for correlation study of Luoping biota palaeogeographic distribution,biological assemblage,special burying,etc.