Features of the Strata for Devonian Queershan Group in Hongshishan Area of Beishan’s Northern Belt, Gansu

Through 1:250000 geological mapping in Hongbaoshi area,Queershan Group is distributed in Shuanggoushan-Queershan area to the northern ophiolitic melange accumulation in Hongshishan in the southern margin of Kazakstan Plate.It consists of a set of celadon intermediate-basic,intermediate-acidic volcanic rocks and volcanic-clastic rocks intercalated clastic rocks.There are Brachiopoda,Anchozoa,Trilobita,Crinoidea et al.fossils in the clastic rocks and limestone.Latontechia cf.latana(Barrande) early formed in Barrandeehoch in Bo xilaiya region.A crospivifer cobedanus varius Kaplun have been discovered in Lower Devonian in Kazakstan region and Hebukeser Formatino of Xinjiang.Eoschuchertella guangxiensis Wang et Rong early formed in Yujiang Formation of Guang xi.This group formed in the litto ral-shallow marine facies which related to the island arc.It can compare with Dananhu Formation,Tousuquan Formation and Hebukeser Formation of Xinjiang.It formed in Early-Middle Devonian.