High Mountain Karren in Northwestern Yunnan, China

Abstract

The high mountain karren rock relief reveals the manner of the formation of the mountain karst surface in the northwestern part of Yunnan at altitudes between 4,000 and 4,600 m. Two dominant factors, snow and rain, decisively influence the formation of the majority of rock forms; in places, particularly on the Shika Snow Mountain, two additional factors are subsoil corrosion and water trickling from overgrown surfaces. Biocorrosion is important for the fine dissection of the rock. Sub-snow rock forms dominate in places where the rock has been covered by snow for a longer period. These are primarily the gently sloping sunless parts of the karren, the lower parts or lower walls of karren, and fissures. Gently sloping sunless parts of the karren are often dissected in various ways so there are sub-snow forms on their lower parts and rock forms carved by rainwater on the higher parts, peaks, and ridges. Rain rock forms dominate on sunny surfaces and parts of the rock that are steep, located higher above the floor, and covered by only a thin layer of snow. The relief and individual rock forms are also influenced by the fissuring and the recrystallization of rock characteristic of the Shika Snow Mountain. The rock masses on the Yulong Snow Mountain are larger and its rock forms have more regular shapes. On the Shika Snow Mountain, rock recrystallization has an important influence on the rock forms, causing fine diversities and often jagged edges of rock forms. By this feature of rock forms and the frequent and originally subsoil rock formation on the Shika Snow Mountain we can distinguish the two described areas of mountain karren. In both mountain areas, the basic characteristics are the same and unique. The rock relief of the mountain karren described in this paper is predominantly dictated by the wider climate and microclimate conditions, the form of precipitation, the alternation of snow and rain, the distribution of precipitation, and the solar exposure of the karren.