A CORRELATION OF THE "XIESHUIHE FORMATION",NANHUAN SYSTEM,WITH A DISCUSSION TO ITS GLACIAL SEDIMENTARY STRACTURES

In the famous Yangjiaping section of Shimen County in the northwest of the Hunan Province,the "Xieshuihe Formation" is one of the controversial units.It has been considered to be correlated to the Liantuo Formation in the Yichang area,or to the Banxi Group in Hunan,or to the Fulu Formation in Northern Guangxi.It seems that the correlation to the Liantuo Formation was confirmed by the recent SHRIMP dating.However,the recalculated age of the Liantuo Formation and the newly achieved age of Sanmenjie Formation are similar and thus raised again the question of how to correlate the Xieshuihe Formation with other stratigraphic units.Our study of recently disappeared glacial sedimentary structures supports the correlation of the Xieshuihe Formation and the Fulu Formation,both representing deposits during the Jiangkou glaciation.We question the correlation between the Xieshuihe Formation and the pre-glacial Liantuo Formation.We propose that the Xieshuihe Formation is correlatable with the "Liangjiehe Formation",which together with the "Tie'si'ao Formation" or "Gucheng Formation" comprises the Fulu Formation.According to the rule of stratigraphic nomenclature,the term "Xieshuihe Formation" should be discarded and replaced by the term Liangjiehe Member,the lower member of the Fulu Formation.