摘要
笔者在进行1∶25万邦多区幅和措麦区幅区域地质调查期间,于措勤县尼雄和尼玛县文部等地发现一套陆相为主的海陆交互相地层。其岩性组合面貌非常特殊,富含植物化石,与坚扎弄组层型剖面可以对比。植物群面貌具有华夏和冈瓦纳植物群中非典型分子的双重性质,无论从植物化石本身、沉积特征,还是从海水进退规律及气候环境等方面综合分析,地层时代宜归晚二叠世,但不排除属中二叠世最晚期的可能性。
During regional geological survey of the1∶250000Boindoi Sheet and Comai Sheet,the authors found a sequence of paralic strata dominated by continental facies at Nyixung of Coqên County,and Om bu of Nyima County,Tibet.It has a very peculiar lithologic assemblage and contains abundant plant fos-sils,and its section may be correlated with the stratotype of the Jianzalong Formation.The flora has non-typical elements of the Cathaysia and Gondwana floras.Analyses of the plant fossils,sedimentary features,canon of trans gressions and regressions ,climate,and environment suggest that it is advisable to assign the age of this sequence of strata to Late Permian;however,the possibility that it is of latest Middle Permian age is not ruled out.The discovery of the Jianzalong Formation has expanded the research range of the Late Permian strata of Tibet,filled in the gaps in the Mid-Late Permian stratigraphic and sedimentologic studies in the Nyixung-Ombu area,and laid a foundation for completing the Permian stratigraphic system in the area,and,in addition,it is also for great significance for the study of the sedimentary facies in this period of time ,reconstruction of the paleogeographic environment ,and comparative study of the strati-graphic evolutions in the Tethyan tectonic development stages of Tibet and its adjacent areas.
出处
《地质通报》
CAS
CSCD
北大核心
2002年第6期339-344,共6页
Geological Bulletin of China
基金
1:25万邦多区幅和措麦区幅区域地质调查项目(编号20001300009161)部分成果。
关键词
西藏
尼雄-文部
晚二叠世
坚扎弄组
Tibet
Nyixung-Ombu
Late Permian
Jianzalong Formation
mixed flora
