Cambrian Trilobite Fauna From The Kushan Formation And The Upper Changxia Formation (Guzhangian),Shandong Province

The Cambrian strata outcrops occur widely in Shandong Province,where the standard sections were established for the traditional Middle-Upper Cambrian System and the chronostratigraphy of the North China.The strata belong to the Sino-Korean Block,and is characterized by the presence of typical carbonate platform deposied in shallow water enviroment,the Cambrian slope facie strata of the South China have made a great progress.With the development of Cambrian research,the Cambrian A global subdivision of the Cambrian into 4 series and 10 stages has been established formally on the basis of the chronostratigraphic study of the global distributed agnostoids species,and the Global Stratotype Section and Point(GSSP)for the Paibian,the Guzhangian and the Wangcunian stages were established in the South China area as exclusive standards for global correlation.The Cambrian research in Shandong started qui-te early but the development has fallen behind that of the South China.There are many unsolved problems of lithostratigraphy and chronostratigraphy in North China.Trilobite zones were established roughly,and definition of the trilobite zonation on the First Appearance Datum(FAD)is of only based on genus-level.These unsolved problems supply the directions and goals for this study.Two Cambrian sections in Shandong Province,the Jiulongshan and Julinshan Section were selected for this study and the Jiulongshan Section is the main Section,while the Julinshan Section is the auxiliary one,the later is studied for the first time.In this study,sampling was done at an interval of centimeter,after fossils identification and comprehensive analysis,the following result were achieved.In the study,trilobite fauna including 74 species assigned to 50 genera and 22 families,were systematically described,and of which the 2 genera and 5 species are new.Nine fossil zones with the FAD of species-level were established.From the bottom to the top,they are the Taitzuia insueta-Poshauia poshanensis Zone,Liopeishania lubrica Zone,Damesella paronai Zone,Blackwelderia paronai Zone,Neodrepanura premes-nili Zone,Diceratocephalus armatus Zone,Fenghuangella laevis Zone,Prochuangia-Paracoosia Zone and Chuangia batia Zone.Among them.Fenghuangella laevis Zone and Prochuangia-Paracoosia Zone are established for the first time in Shandong province.Subdivision and correlation of the Kushanian of the North China with the Guzhangian of the global,as well as the delineation of the boundary between the Series 3 and the Furongian in North China for the first time.The base of the Kushania is defined by FAD of Damesella paronai in North China,while the top of the Kushania is established by FAD of Fenghuangella laevis in North China,the top is also the boundary between the Series 3 and the Furongian.In the meantime,defining the boundary of the Kushan Formation.From extinction,recovery and evolution of the trilobite fauna,with excursion curve of carbonate isotopes,it can concluded that the mass extinction of Damesellidae Kobayashi,1935 by the end of the Guzhangian is approximately synchronous extinction event around the world.The genus Wongia Sun,1924 has been revised,Cyclolorenzella Kobayashi,1960 band Jiulongshania Park,Han,Bai et Choi,2008 were considered as the junior synonymous of Wongia Sun,1924.Two new genera have been established,including Gangchengia gen.nov.and Pseudokotuia gen.nov.,and five species are new,including Gangchengia subcylindrica gen.et sp.nov.;Pseudokotuia quadrata gen.et sp.nov.;Shantungia liui sp.nov.;Shantungia linyiensis sp.nov.and Pseudoyupingia primitive sp.nov.