中国科学院南京地质古生物研究所机构知识库

北祁连山东段纳缪尔晚期(相当于巴什基尔期)植物群,共33属95种植物,其中地方性的土著分子(属、种)占有整个植物群总数的80%以上,华夏植物群(Cathaysia Flora)的典型特征分子较多,如①东方型鳞木类占植物群总数的25%左右,包括从早石炭世延续下来的华夏木(Cathaysiodendron)、多种东方型鳞木(Lepidodendron)、窝木(Bothrodendron)及扁圆封印木(Sigillaria brardii);②由晚泥盆世开始出现的龙潭楔叶(Sphenophyllum lungtanense)、长沙楔叶?(Sphenophyllum?(Tetrafolia)changshaense)、早石炭世的靖远楔叶(Sphenophyllum jingyuanense)到纳缪尔晚期的微缺楔叶(Sphenophyllum emarginatum),这类具有长楔形叶的植物出现得比欧美地区早许多,可能是二叠纪瓣轮叶(Lobatannularia)的最早祖先;③齿叶属(Tingia)在早石炭世晚期已经出现,到纳缪尔晚期(红土洼组)已有三种之多,加上贝叶属(Conchophyllum),这两属一直被认为是华夏植物群的典型代表;④多种早石炭世中、晚期繁盛的真蕨类植物偶脉羊齿(Paripteris)及网羊齿(Linopteris)到晚石炭世早、中期仍十分发育,是华夏植物群早期最显著的特征;⑤早石炭世的畸羊齿(Mariopteris(Karinopteris))继续发育,而后可能演化成大羽羊齿类植物(Gigantopterids)的先祖。本文通过对比研究证实,北祁连山东段的纳缪尔晚期植物群已经进入华夏植物群的早期演化阶段;自从晚泥盆世的沙流水组开始,先后经历了早石炭世的臭牛沟组,靖远组及晚石炭世红土洼组和羊虎沟组(本溪组)代表了前华夏植物群(Procathaysian Flora)演替为华夏植物群的关键地质时期。北祁连山东段亦成为前华夏植物群和华夏植物群早期发育、繁盛之地区,在纳缪尔期可能是华夏植物群的起源和早期演化中心。

Objectives: The Cathaysian flora has long been known as one of the four major floras during the Carboniferous and Permian times,but the origin of the flora still remains as yet unsolved.Methods: Based on a systematic study of the Late Namurian( Bashkirian) flora in the east sector of North Qilian Mountain,there are 33 genera and 95 species as endemic elements( genera,species) accounting for more than 80% of the floral composition.Results: There are many typical elements of Cathaysia Flora,for example,(1) Oriental Lepidophytes take up about 25% of the flora, including Cathaysiodendron from the Early Carboniferous, various Oriental type of Lepidodendron,Bothrodendron and Sigillaria brardii.(2) Sphenophyllum lungtangense and Sphenophyllum ?( Tetrafolia) changshaense, which appeared since Late Devonian, the Early Carboniferous Sphenophyllum jingyuanense,the Late Namurian Sphenophyllum emarginatum. All these species with long cuneiform leaf lamina appeared much earlier in Cathaysia than in Euramerica,from which Permian Lobatannularia might have evolved.(3) Tingia and Conchophyllum had long been regarded as typical representatives of the Cathaysia Flora. Tingia appeared since late Early Carboniferous,and till to Late Namurian( Hongtuwa Formation) three species existed.(4)Many types of Paripteris and Linopteris,which flourished in middle and late Early Carboniferous,were still very common in early and middle Late Carboniferous. This is the most prominent feature in the early stage of Cathaysia Flora.(5) Mariopteris( Karinopteris),which occurred from Early Carboniferous continuously well developed,might be the remote ancestral group of Gigantopterids.Conclusions: This shows the Late Namurian flora in the east sector of North Qilian Mountain was in the early stage of evolution of the Cathaysia Flora,and the Late Devonian Shaliushui Formation,the Early Carboniferous Chouniugou Formation,the Late Carboniferous Tsingyuan and Hongtuwa Formations,together with Yanghugou Formation were the geological period of the evolutionary succession from Procathaysian Flora to the Cathaysia Flora.The east sector of North Qilian Mountain also became an early developed and prosperous area of the Procathaysian Flora and the Cathaysia Flora. It is proved again that the east sector of North Qilian Mountain might be the center of origin and early evolution of the Namurian Cathaysia Flora.