【摘要】 早三叠世华南地区海相沉积广为发育,陆相沉积仅在海南岛和康滇古陆的东缘零星分布,植物化石非常罕见.报道的植物化石采自黔西滇东陆相岔河剖面宣威组顶部、海陆过渡相密德剖面和土城剖面的卡以头组下部,与晚二叠世晚期宣威组植物化石比较,植物类型单调,保存较破碎,共计14属31种,其中以Annalepis为主的石松纲5种;楔叶纲5种;真蕨纲包括7种形态类型;种子蕨纲6种;大羽羊齿类6种;另未鉴定类型2种.从纲级分类看,植物化石以石松纲和种子蕨纲为主要成分,类型较多,数量较大.这些植物化石不仅包括前人报道的该地区同一时期所有植物化石,而且发现许多具有地层意义和演化意义的新类型,如石松类Annalepis(脊囊属)植物化石(A.zeilleri,A.brevicystis)、种子蕨类Peltaspermum(盾籽属)、Lepi-dodendron(鳞木属)等.它们与早三叠世早期的海相动物化石(Bivalves,Ostracods,Brachiopods和Ammonites)同层或之上出现,其地质时代暂属早三叠世早期.鉴于Annalepis在全球三叠纪地层分布时限及广布性,提出以Annalepis的首次出现作为海陆过渡相三叠纪沉积的开始.通过对该植物组合中其成分的生态分析,结合岩性特征,认为黔西滇东地区早三叠世早期处在湿润的气候条件下.更多还原

【Abstract】 Early Lower Triassic plants are little known in China,especially in South China.This paper presents the paleofloral assemblage from the top of Xuanwei and the lower of the Kayitou Formations in western Guizhou and eastern Yunnan,China.Fossil plants in this area(Annularia shirakii,Lobatannularia sp.,Paracalamites stenocostatus,Gigantopteris sp.,Pecopteris sp.,which are all the Permian relicts) from the bottom of the Kayitou Formation described by other people in 1970s are covered.In addition,many important new fossil plants in the evolution during the Permian-Triassic interval,such as Isoetes Annalepis(including A.zeilleri,A.brevicystis),Peltaspermacae Peltaspermum(including P.martinsii,P.lobutalum,P.sp.),Lepidodendron and Stigmaria and so on are also reported.Both the new type and the "Gigantopteris-flora" relicts are characterized with the Early Triassic Induan paleofloral features in South China.This paleofloral assemblage contains 31 species in 14 genera.These fossil plants are in association with an early Lower Triassic marine fauna(Bivalves,Ostracods,Brachiopods and Ammonites).So the geological age of this paleoflora is Early Triassic Induan stage,while the FAD of Annalepis is regarded as the marker,representing the beginning of Triassic.Based on analyzing paleoflora and limnology of the top of Xuanwei and the lower of Kayitou Formations,it is concluded that tropical and humid conditions persisted in western Guizhou and eastern Yunnan throughout the Permian and Earliest Triassic.更多还原