An overview of the geoenvironmental status of the Kullu Valley, Himachal Pradesh, India

The north-south trending Kullu valley between Rohtang in the north and Hansu in the south is a wide and open valley filled with Quaternary sediments along the main course of the Beas River. The valley in the middle is drained by the Beas River and numerous tributaries join it laterally. The tributary channels have deposited large alluvial fans at their mouths which form three distinct levels. The Beas River has deposited alluvial terraces, which are very distinct towards the lower reaches and form three to four levels. The upper slopes and high altitudinal areas are covered with periglacial and glacial deposits. The terrace, fan and hill slopes have provided an ideal geoenvironment for human activities including agriculture, horticulture, dense settlements and other civil establishments. The Kullu Valley is prone to various natural hazards, flash floods and cloudbursts that are very common in this valley due to its peculiar geomorphic condition, high relief of peripheral ridges and impact of monsoon winds. The studies carried out so far indicate that the losses caused by these phenomena both in terms of life and property are mainly due to unwise human interaction with the geoenvironment of the area. The paper gives an overview of the geoenvironmental status of the Kullu Valley and suggests the necessity of undertaking further detailed studies including resource mapping for balanced development of the area.     

情系望天鹅峡谷

望天鹅峰是仅次于长白山的东北第二高峰,海拔2051米,两山之间相距32千米,是长白山区又一独特的地质景观。如果说到长白山是看山、看池、看峰的话。那么到望天鹅峰就是看岩、看水、看瀑布。     

Livelihood diversification of farmers and nomads of eastern transect in Tibetan Plateau

Livelihoods of farmers and nomads in Tibetan Plateau are severely affected by grassland and herbal resources degeneration. How to help them achieve livelihood diversification is a key sustainable development issue. This paper examines livelihood assets, livelihood diversification level and livelihood strategies of farmers and nomads in 3 regions of eastern transect in Tibetan Plateau. The results show that livelihood diversification is a popular strategy. From high mountain gorge region to mountain plateau region and plateau region, livelihood diversification level is reduced, and livelihood activities and proportion of extended livelihood also decrease. Livelihood assets and livelihood diversification level decrease with the increase of elevation, mainly shown in human assets and natural assets. Livelihood diversification level is highly correlative with livelihood assets, mainly shown in natural assets, human assets and social assets. Livelihood improvement strategies of farmers and nomads are still based on existing livelihood assets, mainly raising livestock and digging herbs, and less farmers and nomads consider off-farm employment or doing business. Nomads in plateau region should learn much from experiences of extended livelihoods of people in high mountain gorge region and mountain plateau region. Therefore, aids of governments should focus on relieving restricted factors of livelihood diversification and help them improve their abilities to build up extended type livelihoods.     

情系川西：“长江水学校”四川地震救灾项目综述

一、救灾项目概况 2008年5月12日下午14时28分,在青藏高原东缘的深切割的四川省龙门山高山峡谷区发生Ms8．0级强烈地震（震中位于汶川县映秀镇）。北川-映秀断裂是划分高、低龙门山现代地貌的边界,地形高差极大。在高震级地震导致的强烈地面振动和地表破裂错动的共同作用下,     

怒江峡谷人居环境适宜性评价及容量分析

高山峡谷地区山高坡陡,其发展受到很多因素的限制,人居环境有其特殊性。怒江峡谷区人居环境的主要影响因子为:海拔、坡度、坡向、交通、水资源、土地利用等。将指标分级量化后,采用GIS的空间叠置分析、缓冲区分析等空间分析技术,对研究区人居环境适宜性进行了定量、定位综合评价分析。研究表明,怒江峡谷人居环境适宜区域主要以带状形式分布在河流两侧,其他区域只有零星分布;怒江峡谷人居环境状况与社会经济发展状况的空间分布基本吻合,各县人居环境评价均值与农民人均纯收入相关性达到0.96,各乡人居环境评价均值与农民人均纯收入相关性达到0.76。同时分析了怒江峡谷三县各乡镇的人居环境容量,表明其环境难以承载现有人口。     

泰宁：青年丹霞之美

泰宁,青年期山原-峡谷组合式丹霞的杰出代表; 清晰完整的古剥夷面,密集深切峡谷群和完好的网状谷地,是中生代东南大陆地质演化的典型例证。 宏大的水上丹霞,难解的丹崖岩穴之谜;是泰宁人传承历史文化,推崇自然的真实写照。     

峡谷暖区农业地形气候垂直分层及其农业发展战略

以鄂西南峡谷暖区为例,选取适当的农业地形气候垂直分层指标,运用主成分分析方法对峡谷暖区地形气候进行了垂直分层,以及利用层次分析法对各中垂直农业气候层的农业发展战略进行了决策分析,结果表明,峡谷暖区可划分为三个垂直农业气候层,即温热层、温暖层和温和层。且实行以种植为主,农、林、牧、副、渔并演的方针是峡谷暖区发展农业生产的重要战备措施。     

雅鲁藏布大峡谷河床瀑布的发现及其特征和成因

在中国人首次徒步穿越和全程考察世界最大峡谷过程中,发现了四大河床瀑布群。该回顾了大峡河床瀑布的历史记述,总结了新发现的四大瀑布群具有群体性、多变性和年青性和三大基本特点;分析了瀑布形成的原因,指出陀是在特定的构造和地形环境下,巨大的水动力作用选择和造就了河床差异的地貌＝瀑布群的自然奇观。     

南海北部白云峡谷群富有孔虫砂层沉积特征及发育机制

选取南海北部珠江口盆地白云迁移峡谷群中典型陆坡限制型峡谷为研究对象,利用重力活塞样在峡谷头部晚更新世-全新世沉积地层中揭示出了5个泥质砂层,其砂粒成分包括石英、生物碎屑和较高含量的有孔虫。研究发现,这些富有孔虫砂层不仅表现出底部侵蚀、定年倒置等重力流沉积特征,也表现出了明显的牵引流特征,包括:1）累积概率曲线图与C-M图显示砂层中的粗粒沉积物表现出滚动搬运过程;2）滚动和悬浮组分颗粒分选性较好;3）部分位置可见顶、底岩性突变面和双向交错层理。综合以上证据认为,南海活跃的深水底流对先期重力流沉积的改造可能是形成这些砂层的内在机制。同时,结合三维地震揭示的峡谷内沉积物波以及南海现今水流实测数据,认为峡谷内改造沉积物的底流主要来源于活跃的内波内潮作用,而砂层层理厚度的周期性变化与浮游有孔虫的大量富集可能均是该过程的直接体现。     

台湾峡谷的成因及其对沉积的控制

台湾浅滩陆坡处于被动大陆边缘环境,发育众多的海底峡谷,其中台湾峡谷的走向与沿陆坡向下的侵蚀沟壑明显不同,呈近45°相交;在峡谷的下部又出现一次明显的转向,随后平行于陆坡自西向东延伸,最终汇入马尼拉海沟.本次研究利用多波速水深数据、高分辨地震资料和沉积柱状样,描述了台湾峡谷的地形地貌特征,初步讨论了峡谷的成因及其对沉积的控制作用.台湾峡谷的地形、地貌和沉积特征具有分段性:上段以侵蚀作用为主,呈V形下切,广泛发育滑动、滑塌等重力流类型;中段以侵蚀-沉积过渡作用为主,呈U形,发育内堤岸;下段以沉积作用为主,发育沉积物波,底流对峡谷内部沉积物有明显的改造(reworked sand).台湾峡谷的形成演化与沉积物供给、重力滑动(滑塌)、断裂活动和海底刺穿密切相关:(1)由于陆源碎屑物质供应较充足,陆架边缘沉积物不断向海方向推进,在前缘形成滑动、滑塌,为峡谷的形成提供了动力;(2)断裂活动导致地层破碎,重力流优先侵蚀较脆弱的地层,使峡谷的延伸方向与周边侵蚀沟壑呈明显斜交;(3)海底刺穿形成海山,由于海山的阻挡作用,峡谷的下段转为近东西走向,同时大量沉积物在拐弯处溢流出来形成沉积物波.