摘要
冻融作用是高寒冻土生态环境变化的主要驱动力之一。以大通河源区为研究对象,对冻融作用的类型、成因、分布及其生态环境效应进行分析。结果表明:源区冻融作用发育强烈,主要表现为寒冻风化剥蚀、冻融滑移(包括冻融滑塌和融冻泥流)、冻胀-融沉等作用,对应于源区不同的地形条件和地貌单元。从山顶、山坡到河谷,分别形成山顶寒冻风化剥蚀带;山坡冻融滑移带;山前倾斜平原及河谷平原冻胀-融沉带等几种地貌类型,呈垂直分带规律。各带均存在不同的冻融灾害类型,寒冻风化剥蚀带主要为寒冻剥蚀岩块、碎屑流、崩塌物等;冻融滑移带主要为热融滑塌、冻融坍塌、融冻泥流等;冻胀-融沉带主要为冰椎、冻胀丘、热融洼地、热融沉陷等。同时对其生态环境效应进行分析,指出冻融作用致使高寒草甸严重破坏,荒漠化趋势增强,冻融灾害增多,尤其是冻融滑塌、融冻泥流和冻融沉陷等对高寒冻土环境的危害最大,是近年来大通河源区环境地质条件恶化的主要影响因素之一。
Freeze-thaw action was one of the main driving force of alpine permafrost ecological environment change.This paper took Datong river source region of Qinghai,China as research object,analyzed the type,genesis,distribution and eco-environmental effects of the areas. The results showed that strong action of freeze-thaw exsited in this region,such as the weathering and denudation of gelifraction,frost shifting,of which including freeze-thaw sliding and gelifluction,frost heave and thaw subsidence and so on. Corresponding to the different landscape conditions and geomorphic units,those formed weathering and denudation of gelifraction slopes at the mountain top,freeze-thaw slip at the mountain slopes,frost heave and thaw subsidence at piedmont sloping plain and river plain.Of which frozen soil landform showed a vertical zoning laws. Each zone had different types of freezing and thawing disasters,among them frost denudation rock,debris flow,collapse deposits in the weathering and denudation of gelifraction zone,thaw slump,freeze-thaw collapse,solifluction in the frost shifting zone,pingo,drumlin,thermokarst depression,thermokarst subsidence and other hazards in the frost heave and thaw subsidence zone. Besides,this paper studied the effects of ecological environment and pointed out that alpine meadow was severely damaged,freeze-thaw disasters increased caused by freeze-thaw action. Particularly,freeze-thaw sliding and gelifluction,frost heave and thaw subsidence were the most harmful to the permafrost environment and which had been one of the main factors of environmental geological conditions deterioration of Datong river source region in recent years.
出处
《山地学报》
CSCD
北大核心
2015年第2期141-147,共7页
Mountain Research
基金
中国地质调查局项目:"青海重要能源基地水文地质环境地质调查"(项目编号1212011220971)
国家自然科学基金项目:"高寒融区地下冰融蚀牲及对地下水转化关系影响研究"(项目编号41302190)~~
关键词
大通河源区
冻融作用
寒冻风化剥蚀
冻融滑移
冻胀-融沉
生态环境效应
Datong River source region
freeze-thaw process
the weathering and denudation of gelifraction
frost shifting
frost heave and thaw subsidence
eco-environmental effects
