Discovery of Dinoflagellates from the Tuyiluoke Formation in Tarim Basin

The naming section of the Tuyiluoke Formation is located in the Tuyiluoke Village,about 50 km southeast of the Yingjisha County,Xinjiang.The Tuyiluoke Formation is obviously divided into two members.The lower member consists mainly of grey-yellow,grey-red conglomerate,interbedded with sandstones,about 10m in thickness.And the upper member mainly of brownish-red argillaceous sandstones,about 10m in thickness,interbedded with gypsum and 3 beds of grey-greenish sandy-mudstones.Writers found dinoflagellates fossils(sample No.T2)in the 2nd bed of the grey-greenish sandy-mudstones.The Tuyiluoke Formation,as one of the most important sedimentrelated to the boundary of the Cretaceous and Paleocene in the Tarim Basin,has long been regarded as Cretaceous,in which fossils is rather rare.According to the assemblages of foraminifera and ostracoda,the age of this Formation has been assigned into the Paleocene,and the boundary of Cretaceous and Paleocene has been fixed between the Tuyiluoke Formation and the Yigezya Formation by Hao Yichun et al.(2001)and Guo Xianpu(1990).In this time,because the key fossils are not typical,the dinoflagellates fossils in this Formation are characterized by transitional assemblage between the Cretaceous and Paleocene.This assemblage reflects a warm littoral—shallow sea environment.