Division and sedimentary models for the Palaeogene gypsum mudstones in the Kuqa depression, Xinjiang

In terms of lithologic sequences, the gypsum mudstones in the lower part of the Palaeogene Kumugeliemu Group in the Kuqa depression, Xinjiang are divided, from top to bottom, into five lithologic submembers:(1) No. 1 submember,i. e. the upper mudstone submember dominated by brown mudstone;(2) No. 2 submember, i. e. the upper chemical rock submember dominated by gypsolith and salt rocks;(3) No. 3 submember, i. e. the middle mudstone submember;(4) No. 4 submember,i. e. the lower chemical rock submember dominated by gyposlith and salt rocks intercalated with dolostone, and limestone, and (5) No. 5 submember, i. e. the lower mudstone submember dominated by mudstones. The approaches to the palaeogeomorphological features and sedimentary evolution of the Kumugeliemu Group in this study lead to the proposition of the sedimentary models for individual submembers of the gypsum mudstones in the lower part of the Palaeogene Kumugeliemu Group, and restoration of the palaeogeomorphological and sedimentary features during the early stages of the deposition of the Kumugeliemu Group.