中文摘要：

川西北高原地貌垂直地带性明显：现在流水地貌带海拔高度＜3800m;冰缘地貌带为3800～4200m;冰川地貌带＞4200m;相应的主导地貌过程分别是流水侵蚀、冻融侵蚀和冰川侵蚀.川西北高原是大面积构造隆升背景下冻融侵蚀形成的夷平地貌,花岗岩和石灰岩等结晶岩抗寒冻风化能力强,三叠系砂板岩,抗寒冻风化能力差,前者可以形成冰川发育的高山,后者为融冻地貌等发育的丘状起伏的高原面.南水北调西线一期工程主要位于流水地貌带与冰缘地貌带的交界地带,滑坡、崩塌、融冻土流是工程沿线的主要斜坡灾害,规模多为中小型.工程沿线地区泥石流沟数量多、规模小,但流水地貌带内的部分沟谷可能有大型泥石流发生.融冻土流是该区河流泥沙的主要来源,侵蚀产沙对水库淤积的影响应引起重视.冰缘地貌和流水地貌的交错带部位,地貌过程对气候变化的响应相当敏感.

英文摘要：

Vertical geomorphologic zoning on the Northwest Sichuan Plateau is obvious and elevations for different geomorphologic zones are： fluvial zone〈3800m; glacial margin zone 3800-4200m; and glacial zone〉4200m. Their correspondent principal geomorphologic processes are water erosion, thawing erosion and glacial erosion. The plateau terrain was formed as a result of the thawing erosion under the conditions of vast expanse tectonic uplift. Crystalline rocks of granite and limestone have higher strength against thawing erosion than Triassic epimetasediment rocks of sandstone and slate. Therefore, crystalline rocks are able to form high glacial mountains while Triassic epimetasediment rocks are not. However, Triassic epimetasediment rocks are prone to form hilly plateau terrain. The 1^st stage subproject of the West Route of the South-to-North Water Diversion Project is basically located along the boundary between the fluvial zone and the peri glacial zone, landslides, rock-falls and thawing solifluctions are major slope failure hazards and most of those hazards are of small-medium scales. There are a number of debris flow gullies where small-medium scale debris flows occur frequently in the project area, however, large scale debris flows may occur in the gullies of the fluvial zone. Thawing solifluctions are the main river sediment sources in the area and attentions should be paid to the effects of their sediment production on silting of the planned reservoirs. Geomorphologic processes are very sensitive to climate changes in the boundary area between the fluvial zone and the periglacial zone.