School of Earth Sciences and Engineering，Suzhou University，Suzhou 234000，Anhui，China

Major oxides，as well as trace elements ( including rare earth elements) compositions have been analyzed for the mixosedimentites from Neoproterozoic Jiayuan Formation in northern Anhui，China． The results show that the concentrations of elements are closely related to the relative proportions of carbonates and terrigenous detritus ( varying from 2 /3 to 1 /9 based on petrographic study) ． The ratios between some immobile elements ( e． g． La，Th，Zr and Sc) are constant and then can be used as tracers for the discrimination of provenance and tectonic setting of terrigenous detritus． The results indicate that the terrigenous detritus mainly came from the felsic volcanics related to continental arc，with minor contribution from the old basement． Combined with recent research progresses，these mixosedimentites imply that the Neoproterozoic sedimentation in northern Anhui was probably taken place in a back arc basin during the convergence of Rodinia super continent between 1. 0 and 0. 8 Ga．