黔西滇东早三叠世早期Annalepis(脊囊属)的出现及其地层意义  

THE EARLY EARLY TRIASSIC ANNALEPIS FROM WESTERN GUIZHOU AND EASTERN YUNNAN,SOUTH CHINA

作　　者：喻建新[1,2] 黄其胜[1] Broutin J 杨逢清[1] 

机构地区：[1]中国地质大学(武汉)地球科学学院,武汉430074 [2]巴黎第六大学古植物学和古生态学实验室,法国巴黎75005

出　　处：《古生物学报》2008年第3期292-300,共9页Acta Palaeontologica Sinica

摘　　要：为解决早三叠世卡以头组地质时代和植物组合问题,对采于黔西滇东地区两条二叠系-三叠系海陆交互相界线剖面卡以头组中、下部的植物化石Annalepis(脊囊属)进行深入研究。与Annalepis同层或上部层位见有早三叠世早期的海相双壳类、介形类、腕足类、菊石类及大羽羊齿植物群残余分子,因此可以确定Annalepis在该地区出现于早三叠世早期的印度期(Induan),说明卡以头组(至少中、下部)地质时代属早三叠世早期。推测我国南方的Annalepis在早三叠世始于黔西滇东,随后向北迁移、中三叠世广布于长江中下游地区。建立由早三叠世An-nalepis和大羽羊齿植物群残存分子共同构成的我国南方早三叠世早期植物组合,填补了早三叠世晚期岭文组与晚二叠世B期Gigantonoclea guizhouensis-Ullmannia cf.bronnia-Annularia pinglouensis组合之间的空白。Most of South China was in a vast expanse of ocean during the Early-Middle Triassic due to which the fossil plants are quite rare there. In studying the floras of this area, one was always struck by the absence of the Early Triassic plants. In the recent years, however, the paleobotanists continuously reported that fossil plants were discovered in late Early and Middle Triassic series. Numerous dispersed and well-preserved fossil plants reported in this paper were all collected from the lower part of Kayitou Formation at the Mide and Tucheng sections, Western Guizhou and Eastern Yunnan, Southwestern China. The Annalepis we collected has isolated sporophylls and perfect corm, with some sporophylls retaining the ligules. The occurrence of Annalepis is significant in eastern Yunnan and western Guizhou border where the marine and terrestrial sediments were deposited during Permian-Triassic transition, accompanied by the typical Early Triassic bivalves, ostracods, brachiopods, cephalopods and the important elements of Gigantopteris-Flora as relics. These indicate that the Annalepis originated from southwestern China in Lower Triassic Induan, earlier than in the Yangtze River area. After that, they migrated to the north and were widely distributed in middle and lower reaches of the Yangtze River in the Middle Triassic Anisian and Ladinian, in relation to the marine regression and transgression. The contents of fossils from the Mide and the Tucheng sections are consistent with Yao＇s view （1979）, except that Yao did not find Annalepis. A mixture of the residual components of Late Permian Gigantopteris-Flora and Early Triassic Annalepis constitutes the flora of the early Early Triassic in South China. This assemblage is undoubtedly older than Neuropteridium-Albertia-Voltazia assemblage represented by the Lingwen Formation. The discovery of this flora, therefore, not only fills the gap between the B period of Late Permian Gigantonoclea guizhouensis-Ullmannia cf. bronnia-Annularia pinglouensis assemblage and the la

关 键 词：Annalepis 早三叠世早期 卡以头组 黔西 滇东 华南 

分 类 号：Q914[天文地球—古生物学与地层学]