内蒙古突泉盆地南部中侏罗世植物群初探

    STUDY ON THE MIDDLE JURASSIC FLORA IN SOUTHERN TUQUAN BASIN, INNER MONGOLIA

    • 摘要: 报道了突泉盆地南部牤牛海地区发现的植物大化石15属26种,主要包括有节类Noecalamites sp.、Equisetites sp.,真蕨类Todites goeppertianusT.williamsoniCladophlebis argutulaC.hsiehianaC.shansiensis,松柏类Pityospermum staratschiniP.nordenskioldiPodozamites schenkiP.lanceolotus,银杏类Czekanowskia rigidaGinkgo huttoniGinkgoites cf.SibiricusG.sibiricusG.cf.marginatusG.lepidusVittifoliolum paucinervePhoenicopsis speciosaSphenobailra sp.,苏铁类Nilssonia sinensis以及裸子植物花果和种子Carpolithus sp.等,其中以真蕨类(26.9%)和银杏类(38.5%)占优势,松柏类(19.2%)占一定比重,含少量的木贼类(7.7%)、苏铁类(3.8%)以及裸子植物花果和种子化石(3.8%).结合前人在该地区发现Raphaelia diamensis,指示该套含可采煤层的细碎屑岩组合具有浓厚的中侏罗世早期的时代特征,应为中侏罗世万宝组.根据植物组合中主要发育真蕨纲的Cladophlebis,银杏纲银杏目的GinkgoGinkgoitesSphenobailra以及松柏纲苏铁衫杉科的Podozamites等分子,结合当时整个万宝组植物群面貌以及地层中含煤、发育沉积铁矿等特征,可推测研究区当时具有温暖潮湿的古气候环境.

       

      Abstract: A total of 26 species of 15 genera plant fossils have been discovered in Mangniuhai area, southern Tuquan Basin, mainly including Annelids (Noecalamites sp. and Equisetites sp.), Filicopsida (Todites goeppertianus, T. williamsoni, Cladophlebis argutula, C. hsiehiana and C. shansiensis), Coniferales (Pityospermum staratschini, P. nordenskioldi, Podozamites schenki and P. lanceolotus), Ginkgoales (Czekanowskia rigida, Ginkgo huttoni, Ginkgoites cf. sibiricus, G. sibiricus, G. cf. marginatus, G. lepidus, Vittifoliolum paucinerve, Phoenicopsis speciosa and Sphenobailra sp.), Cycadales (Nilssonia sinensis) and Gymnosperms seed (Carpolithus sp.). Among them the Filicopsida (26.9%) and Ginkgoales (38.5%) are dominant, with Coniferales accounting for 19.2%, a small number of Equisetales (7.7%), Cycadales (3.8%) and Gymnosperms (3.8%) as well. Combined with the previous discovery of Raphaelia diamensis in the area, it is revealed that the minable seam-bearing fine clastic rock assemblages have the characteristics of early Middle Jurassic, belonging to Wanbao Formation. Based on the fact that the plant assemblages mainly consist of Cladophlebis, Ginkgoales like Ginkgo, Ginkgoites and Sphenobailra, and Cycads Podozamites, together with the flora appearance in the entire Wanbao Formation at that time, as well as the features of coal seam and developed sedimentary iron, it is inferred that the study area was in a warm and humid paleoclimate environment then.

       

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