西藏尼玛一带上白垩统竟柱山组的厘定及其意义

Determination and Significance of Upper Cretaceous Jingzhushan Group of Nima Region,Tibet

西藏尼玛县城西-色林错一带发育一套山间河湖相的红色碎屑岩系,属红色磨拉石建造。该红色碎屑岩系底部不整合于下白垩统及其以下层位之上。其时代归属尚不统一,有划归为上三叠统巫嘎群,有划归为古近系始新统牛堡组。2000～2002年作者在尼玛县城西、双湖区南措折乡宋我日分别测制了剖面,2002年又在尼玛县城西剖面补采样品,获得丰富的孢粉化石。根据所含孢粉组合特征及时代,将其划归上白垩统竟柱山组。

A red clasolites of mountainous-river-lake facies of red molasse, was developed at Yiselincuo west to the Nima County of Tibet. The indistinct red clasolites unconformitied opon Lower Cretaceous and the followed stratigraphic positions, and its time ascription is or as Wuga Group of upper triassic series, or Niubao Group of Eocene. The author measured and made the section plane, and found few sporopollen fossil successively, by the 1：250 000 regional geological reconnaissance of Nimaqufu and RebuKafu in Songwori, Nancuoze Township, Shuanghu District of Nima County during 2000 - 2002, and collected samples and ample sporopollen fossislof section plane at the west to Nima County in 2002. In this way, the author defines it as Upper Cretaceous Jingzhushan Group according to the sporopollen assemblage contained and characteristics and the age.