SEDIMENTARY CHARATERS OF BRAIDED AND LOW—SINUOSITY STREAMS IN SANDO FORMATION OF LOWER TERTIARY, NORTHERN JIANGSU PROVINCE

In the sediments of paieostreams,there are certain amount of rare mineral deposits,such as gold,diamond,uranium,platinum and monazite,etc.and some important oil/gas reservoirs as well.Therefore,it is practi-cally significant to study the ancient fluvial sediments.Up to the present,much analysis have been made on the sedimentation of the sinuous streams,but those on braided streams are not enough.Taking Lower Tertiary fluvial sedimentation in Sando Formation of Northern Jiangsu as an example,the characters of fluvial sedimentation,and the relation between braided streams and low-sinuosity streams are discus-sed in this paper.For the recognition of the sedimentary characters of such streams,especially of the characters in ancient stratigraphic profiles,the author of this paper establishes a typical profile as a model.