西藏申扎地区晚石炭世—早二叠世冈瓦纳相腕足类动物群再研究

Late Carboniferous-Early Permian brachiopod fauna of Gondwanic affinity in Xainza County,northern Tibet,China:Revisited

西藏申扎地区德日昂玛-下拉剖面永珠组中上部和昂杰组的腕足类动物群可以与国内、外冈瓦纳相和亲冈瓦纳相地区的腕足类动物群进行对比,但又显示出其独特的一面。将其自下而上划分为4个组合,永珠组中上部为Reedoconcha xizangensis-Spinomartinia xainzaensis组合、Cimmeriella mucronata-Reedoconcha excellens组合和Trigonotreta magnifica-Bandoproductus in-termedia组合,昂杰组为Aulosteges ingens-Punctocyrtella nagmargensis组合。按照国内、外冈瓦纳相、亲冈瓦纳相地区及华夏特提斯地区腕足类的时代意见,永珠组中部腕足类组合的时代为晚石炭世巴斯基尔期,上部2个腕足类组合分别为早二叠世萨克马尔早期—萨克马尔晚期,昂杰组的腕足类组合的时代为早二叠世亚丁斯克期。

The brachiopods faunas in the middle and upper parts of the Yunzhug Formation and the Angjie Formation in the Deri＇angma-Xiala section in the Xainza area, northern Tibet, may be correlated with those in Gondwana and peri-Gondwana areas in China and abroad but show their unique aspects. They may be divided into four assemblage zones （A. Z.）, i.e.： the Reedoconcha xizangens-spinomartinia xainzaensis A. Z., Cimmeriella mucronata-Reedoconcha excellens A.Z. and Trigonotreta magnifica-Bandoproductus intermedia A. Z. in the middle and upper parts of the Yunzhug Formation and the Aulosteges ingens-Punctocyrtella nagmargensis A. Z. in the Annie Formation. According to the present study of the ages of brachiopods in the Gondwana and peri-Gondwana provinces and Cathaysia-Tethys province, the brachiopod assemblage zone in the middle of the Yunzhug Formation is Late Carboniferous Bashkirian in age, the two brachiopod assemblage zones in the upper part are Early Permian early Sakmarian and Late Sakmarian in age, and the age of the brachiopod assemblage zone in the Angjie Formation is Early Permian Artinskian.