滇西亲冈瓦纳微古植物的发现及其地质意义

On the Discovery of a Gondwana Affinity Microflora from Baoshan,West Yunnan and Its Geologic Significance

本文首次报道滇西保山丁家寨组孢子花粉４０属５５种，其中新种Ｐｌｉｃａｔｉｐｏｌｅｎｉｔｅｓｂａｏｓｈａｎｅｎｓｉｓ１个。丁家寨组的孢子花粉组合是一个以冈瓦纳植物地理区分子为主，兼有少量华夏植物地理区和其它植物地理区分子。丁家寨组的Ｐａｒａｓａｃｉｔｅｓｄｉｓｔｉｎｃｔｕｓ－Ｍｉｃｒｏｂａｃｕｌｉｓｐｏｒａｆｅｎｔｕｌａ（ＤＦ）孢子带可与冈瓦纳植物地理区Ｐａｒａｓａｃｉｔｅｓ孢子带比较，时代为阿舍尔阶（Ａｓｅｌｉａｎ）萨克马尔阶（Ｓａｋｍａｒｉａｎ）。丁家寨组的微古植物研究不仅有重要的地层学和古生物学意义，而且对研究冈瓦纳大陆与欧亚大陆之间的关系有着十分重要的意义。

Palynomorphs are recovered for the first time from the Dingjiazhai Formation in Baoshan,West Yunnan.The palynoassemblage is well diverse and includes 40 form genera,55 species,of which one new species, Plicatipollenites baoshanensis .The assemblage is dominated by radially symmetrial triletes monosaccates and non_taeniate bisaccates. The miospore assemblages assigned to the Parasaccites distinctus_Microbaculispora fentula (DF)zone of the Dingjiazhai Formation are characteristically dominated by Gondwana microfloral elements which often constitutes up to 80 per cent of more of the assemblages.Many typical forms of the Gondwana microflora occur in this assemblage,such as Parasaccites distinctus Tiwari, Brakarites rotatus (Balme and Hennelly)Bharadwaj and Tiwari, Potonieisporites neglectus Potonie and Lele, P.magnus Lele and Karim, Plicatipollenite densus Srirastova, Microbaculispora fentula Tiwari, M.tentula Tiwari, Interradispora daedala Foster, I.robusta (Foster) Foster, Horriditriletes ramosus (Balme and Hennelly)Bharadwaj and Salujha, Marsupipollenites triradiates Balme and Hennelly and so no. The microspores features of both in West Yunnan and Caythaysia microflora shows the microfloral natures in between Gondwana and Caythaysia and West Yunnan was such closer to the Gondwanaland in terms of Clayton′s Microflora(1985).The Parasaccites distinctus_Microbaculispora fentula (DF) zone may roughly be correlated with the Parasaccites zone of Kyle(1977) belonging to Asselian to Sakmarian in age. Based on palynological data,the Microflora Province,Palaeoclimate and Palaeogeography are discussed.