World Natural Heritage: Wulingyuan Scenic and Historic Interest Area (3)

Natural heritage value:

Valuable geology and landform

The Wulingyuan Scenic and Historic Interest Area is in the third uplifted zone of the Neocathaysian structural system. Throughout the long geologic history, it has roughly experienced the Wuling-Xuefeng, Indosinian, Yanshan, Himalayan, and neotectonic movements. Among them, the Wuling-Xuefeng movement laid the basic structure of this area, the Indosinian movement shaped the basic geomorphic framework and the Himalayan and neotectonics movements were the most basic internal factors for the formation of the rare karst formation in the Wulingyuan area.

The stratums that form the sandstone peak forest landforms are mainly composed of the Yuntaiguan formation and Huangjiadun formation originating from the middle and late Devonian period of the Paleozoic era and have the characteristics of littoral clastic rocks. The rocks are pure, thick and flat, and have vertical joints, exposed as the syncline profile, reflecting the basic geological environment and conditions for the formation of sandstone peak forest landforms. The water erosion, avalanches, living beings' biochemical actions and physical weathering are the essential external conditions. Therefore, this kind of landforms was formed under the long-term interactions of the gravity inside and outside earth in a specific geological environment.

Strange and beautiful landscapes

The quartz sandstone peak forest landforms: Wulingyuan has a total of 3,103 stone peaks, ranging from altitudes between 500 to 1,100 meters, and the heights of the peaks range from tens of meters to 400 meters. The peak forest is beautifully shaped, looking like people, celestial beings, animals, or many other things. The landform features of the Wulingyuan quartz sandstone peak forest is purity and thickness, for 75 to 95 percent of the peak, there is quartz and rock stratum that is over 520 meters thick. Furthermore, the peak has lit-par-lit structure, namely the thin or super-thin mica sandstones or shales are placed in the thick layers of quartz sandstones, which is conducive to beautifying natural formations. The rocks are exposed as syncline structures and have flat contours (mostly 5 to 8 degrees, but the maximum is up to 20 degrees). This helped the stability of the rocks and provided a prerequisite for the formation of the peak forest. The characteristics including vertical joints as well as 15 to 20 meters of space between every two peaks had provided topographic conditions for shaping different styles of peak forests and deep canyons.

Based on the above factors plus various external forces during the regional neotectonics movement, including intermittent uplifts, tilting, water erosion and cutting, gravity, physical weathering, biochemical and root wedging, the peak forest structures of the mountains were formed according to complex natural evolution, and shows high, flat, steep and other features.

Erosion landforms: the erosion landforms in the Wulingyuan Scenic and Historic Interest Area is mainly exposed in where the carbonate was distributed during the Permian and Triassic era, with an area of nearly 31 square kilometers, and can be divided into five sub-categories, known as the typical representative of the "west Hunan-type" karst landscape. The main shapes include the karst vein, trace, doline, karren, groove, stone forest, low-lying land, membrane, funnel, ponor, silo, scuttle, underground river, and karstic spring. The karst caves are mainly located to north of Suoxiyu River Valley and southeast of Tianzi Mountain and there are dozens in total. The most typical is the Huanglong Cave, which is called the "treasure house of speleology," and has great value in terms of tours and adventures for tourist and speleologists.