The lithofaces, Mn-bearing sedimentary filling and palaeogeographic pattern of Early Datangpo Stage and implied for manganese in the northeastern Guizhou Province

The Cryogenian (Nanhua) Period "Datangpo type" manganese deposits in northeastern Guizhou Province constitute the most important manganese resource base of China, and the lithofacies-paleogeographical environment is the most important orecontrol factor. Based on analyzing the lithology and age histogram of detrital zircon U-Pb ages of Qingshuijiang Formation, Liangjiehe Formation, Tiesi'ao Formation and Datangpo Formation, the authors present the stratigraphic division of Nanhuan System. Totally, there are four level II basins, twelve level III basins and eleven Mn-bearing basins according to distinct sedimentary filling patterns in northeastern Guizhou Province. It is suggested that there are nine types of palaeogeographic units in early Datangpo Age based on identifying fourteen types of lithofaces in 1st member of Datangpo Formation. Furthermore, the authors compiled the lithofacies paleogeographic map of Early Datangpo Age of Cryogenian (Nanhua) Period in northeastern Guizhou Province. In conclusion, under the background of continental margin rifting, the authors hold that the sedimentary environment of early Datangpo Age in the study area belonged to the barrier coastal system of continental margin, and the typical "Datangpo type" manganese deposit was closely related to the deep-water limited basin with rapid subsiding behind the barrier.