Sichuan Background of GEF Project
Section 1 Overview of Natural Environment
一、地理位置 I. Geographical position
Sichuan province is located in the inland hinterland of Southwestern China, specifically between longitude 92°21′—108°12′E and latitude 26°03′—34°19′N, bordering 7 provinces/municipalities/regions of Western China, namely Yunnan, Guizhou, Chongqing, Tibet, Qinghai, Gansu and Shaanxi. As it serves as a bond between Eastern China and Western China and a bridge linking Southwestern China with Northwestern China, it plays a very important role in ecological niche and geographical location.
1、四川省岩溶区主要分布在川西南山地区、川南盆地边缘区、川东平行岭谷区、盆中丘陵区，介于东经100 °07 ′— 107° 15′、北纬 26°10 ′—30 ° 41′之间。石漠化土地以川西南山地区和川南盆地边缘区为主。
1. The karst regions in Sichuan are mainly distributed in the mountainous area of Southwestern Sichuan, the basin margin of Southern Sichuan, the parallel ridge-valley region of Eastern Sichuan, and the mid-basin hill region, specifically between longitude 100°07′—107°15′E and latitude 26°10′—30°41′N. The rocky desertification land is mainly distributed in the mountainous regions of Southwestern Sichuan and the basin margin region of Southern Sichuan.
2. The desertified land in Sichuan is mainly distributed in Northwestern Sichuan, specifically between longitude 97°21′18″～104°24′21″E and latitude 27°07′28″～34°19′20″N, facing Cangdu, Tibet across the Jinsha River to the west, bordering Yushu and Guoluo Tibetan Autonomous Prefectures in Qinghai, and Tibetan Autonomous Prefecture Gannan and Longnan city in Gansu to the north, Mianyang, Deyang, Chengdu, Ya’an as well as Mianning County and Decang County in Liangshan Prefecture to the east, Panzhihua city and Dêqên Tibetan Autonomous Prefecture in Yunnan to the south.
二、地质地貌 Geology and geomorphology
Sichuan is located on the first and second ones of the three major continental relief stairs in China, covering a portion of the first-stair Qinghai-Tibet Plateau and the second-stair Sichuan Basin and its surrounding mountains, its relief taking on a huge height difference of noticeably high west and low east. Sichuan province can be roughly divided into Sichuan Basin and Western Sichuan Plateau. The latter mostly has an altitude over 3500m, while the former reaches an altitude ranging from 400 to 2000m. Sichuan Basin is one of the four major basins in China, covering an area of 165,000km2. It is surrounded by many mountains such as Qionglai Mountains, Min Mountains, Daba Mountains and other mountains. The central portion of the basin varies from 400 to 800m in altitude, slanting slightly southward, where the Min River, Tuo River and Jialing River from the northern mountains flow into the Yangtze River to the south. The Western Sichuan Plateau at an altitude ranging from 3000 to 5000m accommodates many high mountains (e.g. Shaluli Mountains, Great Snow Mountains) and great rivers (e.g. Jinsha River, Yalong River, Dadu River) winding through deep valleys, both assuming a north-south strike. Sichuan has various landforms under four major categories: plain, hill, mountain and plateau. The third one is the main landform, followed by the fourth one.