Abstract: Marine Jurassic rocks occur along the Nuchiang drainage area. They can be divided into four formations. Lying disconformably or unconformably on older rocks, the Mengga formation (J21), 545-1000 m in thickness, consists mainly of purplish red arenaceous shale and sandstone intercalated with dolomitic limestone, oolitic limestone and lenticular gypsum. Near Liuwan, west of the Paoshan city, basalt occurs in the upper part of the formation. The Liuwan formation (J22), 35-666 m in thickness, consists of Shelly argillaceous limestone rich in brachiopods. The Long-hai formation (J23), about 200m in thickness, consists mainly of yellow argillaceous shale and siltstone containing, in the lower part, a rich pelecypod fauna. Lying disconformably on the Longhai formation the unfossiliferous Longkan formation (J3) is chiefly composed of reddish yellow quartzose sandstone and conglomerate, of which the exposed thickness is 285 m.The fossiliferous Middle Jurassic of this region may well be correlated with contemporaneous deposits of northern Tibet and southern Chinghai on the one hand, and with the Namyau series of the Northern Shan State on the other.
Publication Year: 1973
Publication Date: 1973-01-01
Language: en
Type: article
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