The different views on the age, lithofacies and contact relationship of the strata related to the ophiolite melange belt in northeastern Jiangxi Province lead to the different explanations on the history of geological evolution of South China. The isotopic ages obtained from igneous blocks of the melange were mostly between 900 to 1000 Ma. On the other hand, some Paleozoic microfossils were found from a volcanic-sedimentary sequence (Dengshan Group) associated with the ophiolitic belt, but the exact ages of those fossils could not be determined. The paleogeographic analysis indicates that in Early Paleozoic there was not a “Jiangnan Paleocontinent”, but a deep-water “Jiangnan Basin” in northeastern Jiangxi Province . Late Ordovician pyroclastic deposits widely spread in South China, but their source is still unclear. Based on the lithofacies paleogeographic analysis, the eruptive center probably located in northeastern Jiangxi at that time, that just matched with the Dengshan Group formed in the volcanic island-arc environment. So that implies the Late Ordovician age to the Dengshan Group. In early Silurian the Jiangnan Basin closed and a Caledonian fold belt formed between the Yangtze Block and Cathaysian Block. The ophiolitic belt in northeastern Jiangxi Province was a suture between the fold belt and the Cathaysian Block. Here the distance between the two blocks are smallest in South China and rocks were strongly compressed, resulting in major uplift and stronger erosion. Therefore, Lower Paleozoic were difficult to be preserved in the area, and the Dengshan Group was just their remains.
