Composite stratigraphic division of the Mesoproterozoic Shuangqiaoshan Group in northern Jiangxi

The Mesoproterozoic Shuangqiaoshan Group as the widespread pre-Sinian low-grade metamorphic rock series in northern Jiangxi has long been the frontier field in the studies of the geology of the pre-Sinian strata. The Group is characterized by simple lithology, severe deformation of the rocks, and absence of marker beds. The authors contend that it is imperative to subdivide the internal primany sedimentary structures so that the stratigraphic division and correlation can be effectively made.