甘肃窑街植物群的地质时代及古地理区系研究  

Geological age and paleaogeographical study of the Yaojie Flora in Gansu Province

作　　者：辛存林[1] 王露菡 季健健 张亚梅 王晶菁 XIN Cunlin;WANG Luhan;JI Jianjian;ZHANG Yamei;WANG Jingjing(College of Geography and Environmental Science,Northwest Normal University,Lanzhou,730070)

机构地区：[1]西北师范大学地理与环境科学学院,兰州730070

出　　处：《地质学报》2019年第2期302-316,共15页Acta Geologica Sinica

基　　金：国家自然基金项目(编号41262001);甘肃省科技支撑基金(编号1104FKCA116)共同资助的成果

摘　　要：本文对甘肃窑街组古植物群及古地理进行研究,共发现植物化石31属63种,以银杏类(36.5%)和真蕨类(22.2%)繁盛,松柏类(17.5%)和苏铁类(15.9%)占一定比例,楔叶类(6%)、不明位置的果与穗(1.9%)为特征。在此基础上结合植物群组成分子指示的时代特征,以及与国内外同期其它植物群的对比,认为窑街组植物群的地质时代为中侏罗世早中期(Aalenian-Bajocian)。利用聚类分析法对甘肃窑街及其余11个研究较为细致的中国北方中侏罗世植物群进行对比,探讨甘肃窑街古地理归属,并对中国北方中侏罗世植物区进行初步划分。利用分支生物地理分析法研究甘肃窑街植物群的亲缘关系,结果表明窑街中侏罗世植物群与内蒙古高头窑植物群关系较为亲近;讨论了甘肃窑街新发现的屈囊蕨属在中国的地理分布特征,发现其分布与中国北方中侏罗世的初步区划结果吻合。The paleoflora of the Yaojie Formation in Gansu Province and its paleogeographcial features were studied in this paper.A total of 31 genera including 63 species were identified,including newly discovered Gonatosorus shansiensis.Ginkgopsida(36.5%)and Filicopsida(22.2%)are most abundant,and Coniferopsida(17.5%)and Cycadopsida(15.9%)are less abundant,followed by Sphenoposida(6%)and Fructus et Semina(1.9%).On the basis of fossil compositions and time characteristics indicated by the flora,comparison with some similar floras at home and abroad,suggest that the geological age of the Yaojie Formation should belong to the Aalenian to Bajocian period.The cluster analysis was employed to compare the Yaojie flora of Gansu with other 11 flora from northern China to discuss the geographic attribution of the Yaojie flora,and the Middle Jurassic flora in northern China was preliminarily classified.In addition,the branch biogeographic method was used to analyze the affinity relation of the Yaojie flora.The results show that the Middle Jurassic Yaojie flora has close affinity to the Gaotouyao flora in Inner Mongolia.This study also investigated the geographical distribution characteristic of the genus Gonatosorus in the Mesozoic of China,which was newly discovered Yaojie of Gansu.It is basically in agreement to the division of the Middle Jurassic in northern China.The results show that Yaojie flora belongs to the Siberian flora region and has a close relationship with Gaotouyao flora in Inner Mongolia,the two floras can be classified as a small plant subordinate in Siberian flora region,and the boundary between the Siberian and Europe-China flora region is supposed in the south of Yaojie flora.

关 键 词：窑街 中侏罗世 古植物群 地质时代 古地理区划 

分 类 号：Q914.5[天文地球—古生物学与地层学]