In Zhangjiajie Global Geopark, sedimentary rocks are mainly distributed, metamorphic rocks are very few, and magmatic rocks are not produced. The rocks that form the Fenglin landform of Wulingyuan sandstone in Zhangjiajie are the Yuntaiguan Formation, which is composed of giant thick layer or thick layer fine grained quartzite sandstone with thin layer siltstone. The quartz content is as high as 90%, and the cement is mostly iron and siliceous. The chemical properties of quartz, iron and siliceous cement are very stable in the supergenetic environment and have strong corrosion resistance.
On the other hand, because of its hard physical properties, it forms a strong base for the peak column. The top of the Huangjiadeng group of iron cement purplish red thick quartz sandstone (iron ore layer) constitutes the top of the peak column, just like putting on a strong helmet to the peak column, forming a true "iron cap". All these are the material basis for the formation and preservation of Wulingyuan sandstone peak forest landform in Zhangjiajie. In the super-thick quartz sandstone, there are several thin silty soft layers. Because of its weak resistance to weathering and erosion, it is easy to weathering and denudation. On the one hand, it reduces the firmness of the peak column, but on the other hand, it is also conducive to the sculpture of a single peak column, forming a large number of lifelike anthropomorphic peak column shape landforms.
