1. The rocky desertified land in Sichuan is patchily concentrated in the mountainous zone of Southwestern Sichuan, especially of the Panzhihua-Xicang Yanyuan erosion strath basin, where the rocky desertification types are most and the area of such land largest; there is also a relatively large potential rocky desertification area in the Mount Emei-Daliang Mountains erosion mountainous zone; such land is discretely scattered in the peri-basin mountainous zone. The strata within the rocky desertification zone are mostly Triassic and Permian limestone and dolomitic limestone strata; in the rocky desertification development zone, the landform is mainly medium and low mountain rocky hill sloping field, solution monadnock and strath basin.
2. The northern portion of Sichuan desertified zone comprises complete mountains and plains surrounded by high mountains at around an altitude of 4000m, having the same type of landform as the area adjacent to Tibet Autonomous Region and Qinghai. The portion takes on a high-south low-north relief, being a lake-basin hollow roughly centering around Tangke at the Yellow River bight, the altitude reaching 3500m or so; there Quaternary unconsolidated deposits are extensively distributed with many swamps, lakes and hollows. The Serxu-Sêrtar region to the northwest has a gentle mountain relief and broad plain rivers. The central Garzê-Litang region is the highest plateau in the province where the altitude mostly reaches above 4000m with a rising relief, round mountain top and relatively complete plateau surface. The eastern and southern portions are a transitional zone between Eastern Sichuan Basin and Western Plateau, where the relief takes on a high-north low-south feature with high mountains and deep valleys. Most mountains have steep tops and an altitude above 5000～6000m. The relative height difference between such mountains usually exceeds 1000～2000m. The height difference between the Dadu River and the peak of Mount Gongga hits 6400m.
三、气候 III. Climate
The climate in Sichuan province is regional, transitional and complex. By water, heat and sunlight conditions, it can be divided into three climatic zones: mid-basin subtropical humid climate zone, Southwestern Sichuan mountain subtropical sub-humid climate zone and Northwestern Sichuan alpine plateau paramos climate zone. It features various climate types, huge vertical differences, obvious monsoon climate, striking regional characteristics and various climate damages.