Figure 2: Sketch map showing the distribution of the co-sedimentary system of evaporites and source rocks in the middle part of Member 4 of the Shahejie Formation in the Dongying depression. 1. halite, gypsum; 2. limestone, dolomite; 3. mudstone; 4. wells; 5. faults; 6. boundary of different sedimentary systems; 7. the Wells for the samples coring.