Contourites and Their Sedimentary Model in the Lower Triassic Daye Formation,in Southern Hunan Province

It is the first time to discover contourites in Hunan Province, China. The main sedimentary structures in the contourites include convergent cross-bedding, flyschoid bedding and contour current marks. This paper deals with the vertical changes in physical and chemical properties of water bodies in deep-water zone, which are responsible for the formation of ordered structures, i. e., a series of graded beds and mutation beds. The different flow regimes of contour currents can give rise to distinct sedimentary structures which are ascribed by the author to the structural beds on the basis of the mechanism for the formation of the sedimentary structures, thus resulting in the establishment of a tentative sedimentary model for the contourites. Furthermore, the author suggests in the study that flyschoid bedding may be included in the sedimentary structures in contour current deposits, so that the implications for contour currents may be extended. This is of special theoretical significance.