赣东北上侏罗统鹅湖岭组下界的探讨

PROBE ON THE LOWER GROUP OF EHULING FORMATION OF UPPER JURASSIC SYSTEM IN NORTHEAST JIANGXI

本文分析了赣东北上侏罗统鹅湖岭组下界划分的现状及产生分歧的原因。提出了以岩性岩相为划分依据，结合火山旋回分析，将鹅湖岭组与喷发相相对应，因而其下界应置于沉积喷发相与喷发相的相交界面上。从而将北京地质学院指定的打鼓顶组建组剖面上的“打鼓顶组”并入鹅湖岭组，将赣东北其它地区的鹅湖岭组下界由安山岩层的顶界处上移至安山岩层之上灰绿色砂岩层的顶界处。

This paper analyzes the existing state of the stratigraphic division of the lower group of Ehuling Formation and the reason resulting in difference. Based on the features of volcanic factes, volcanic cycle analysis, the lower group of Ehuling Formation is located on the interface of change of factes between sedimentary--eruption factes and eruption factes. With the result that 'Daguding Formation' on standard see'non of Daguding formation proposed by Beijing Geological Institute should be a partof Ehuling formation, and the lower group of Ehuling formation should be migratedup from the upper group of andesite layer to the upper group of gray--green sandstonelayer.