Much sedimentary rock, less metamorphic rock and no magmatic rock occurred in the park.

The rock, forming Zhangjiajie peak forest landform, thick and huge stratum of quartz sandstone mingled withthin layer of siltstone, content of quartz over 90%, with irony and siliceous cement, was chemically very stable in hypergenic environment. On the one hand, its hard structure formed the solid foundation of peak-poles(see Photo.2-1). The irony cemented purple mid or thick quartz stratum in Huangjiadeng Formation formed the top part of stone peaks, like a solid irony safety helmet on the peaks. It’s a real ‘Irony hat’ (See Photo. 2-2). This is the material foundation of peak forest forming and preserved till now. Feeble argillaceous cement thin layers, which are easy of weathering and denudation, occurred in giant stratum of quartz sandstone. The variance of this rock’s hardness resulted in different ability to resist weathering. On the other hand, the traits were in favor of sculpting individual peak into different shapes. So, some lifelike sculpture landform, such as man-like and substance-like peaks, was formed.

Hematite rock Lime stone Quartz sandstone Shale