Development characteristics and research value of red carbonate stone forest in the Xiangxi geopark

The red carbonate stone forest is one of the most important geologic relics in the Xiangxi geopark. This forest formed in Ordovician Dawan Formation and Guniutan Formation, concentrated in the canyon-slope area along the Youshui-Mengdong river. Its exposed area is about 84 km2, and can be regarded as the largest known Ordovician red carbonate stone forest landscape in the world. The red stone forest has various forms and good landscapes, including astower, flame, wall, sword, column, and andcone. In geological genesis, similar to the other karst stone forests, the formation of the red stone experienced stages of stratigraphic sedimentation, tectonic uplift and weathering erosion. The suitable palaeogeographic environment, fissure morphology, tectonic uplift, warm climate and abundant surface and underground water systems are the major conditions for the development of the red stone forest. However, due to some special factors, such as complex lithological composition, thin strata and different dissolution, the red stone forest has obvious superposition shape of vertical and horizontal dissolution marks, with unique natural beauty,which is quite different from some other well-known stone forests, for example the Yunnan stone forest and Xingwen stone forest. This phenomenon might be attributed to a unique process of formation. In colour, the red stone forest shows amazing changes in different kinds of weather and different times of the year,which may be caused by algae on the surface of the pillars. Besides the southwest of China, the distribution of Ordovician red carbonate stone forests is very limited, only reported of Satun of Thailand with prominent rarity. Just due to the scarcity, many targeted studies remain in infancy, which is worthy of further in-depth research by scholars of various disciplines.