Storm-Deposits in Upper Proterozoic in Southeastern Huabei Sino-Forean Massif

The area of northern Jiangsu and Anhui provinces locates on the southeastern edge of Huabei massif (Sino-Korean massif),and is one of the key areas for the division and correlation of Upper Proterozic in China. Since late 80's,some geologists have reported or studied some storm-deposits of the Upper Proterozoic (Ge Ming et al.,1987;Qiao Xiufu,1987;Qiao Xiufu et al.,1989). However,their researches are concerning only on the storm-deposit levels in Zhangqu Formation and Weiji Formation. Through the research in this area during recent years,the authors have discovered some storm-deposits in Liulaobei Formation,Niyuan Formation, and Wangshan Formation in the Upper Proterozoic. This paper is mainly carried out to approach the characteristics of the newly recognized storm-deposits in some aspects such as types of the tempestites,storm-generated sedimentary structures, sectional textures of tempestites, and sedimentary environment of tempestites. According to our research,the major rock types of the storm-deposits include autochthonous calcirudite,allochthonous calcirudite, turbidite-generated calcisiltite and micritic limestone, etc. Storm-generated sedimentary structures include different scour or truncation structures (e. g., flate, wave-like, complex and irregular, etc. );hummocky cross-stratification (which can be clasificlassified into two types; simple and complex); swaley cross-stration, swaley cross-stration,and thin graded bed. Moreover,the sectional texture of the newly recognized storm-deposits can be classified into 9 types. Most of them are incomplete,and some of them belong to complex ones,which mean the existence of episodical storm activity. The sedimentary environment of tempestites,we think,includes three types:subtidal zone in open shelf, plateform edge gentle ramp,and subtidal zone in confied plateform.