Revision of the Late Cretaceous Maodian Formation of the Ganzhou Group in Jiangxi Province

Abstract: On the basis of the latest data of 1:50000 regional geological mapping, the authors revise the Maodian Formation of the Ganzhou Group in the Lithostratigraphic units of Jiangxi Province. Five types of sedimentary interfaces of different natures are identified in the orthostratotype of the original Maodian Formation; they are the sedimentary unconformity, overlapping unconformity, disconformity, facies change surface, and synthetic stacked surface, and thus the original Maodian Formation is divided into two different formation-rank lithostratigraphic units. According to the naming principle of lithostratigraphic units, the middle and lower horizons of the original Maodian Formation below the overlapping unconformity are assigned to the Maodian Formation of the Ganzhou Group, and the association of basalt-pyroclastic-sedimentary rocks developed in the horizons is separated from the horizons and the Chenkeng Volcanic Member is established separately. The coarse clastic sedimentary rocks in the upper part of the original Maodian Formation above the overlapping unconformity are assigned to the Honggang Formation of the Late Cretaceous Guanxi Group. The revised Maodian Formation only corresponds to the middle and lower horizons of the original orthostratotype Maodian Formation, and it is subdivided into three members, i. e. the Lower Member, Chenkeng Volcanic Member, and Upper Member.