PALEOSOLS OF SANDY LANDS AND ENVIRONMENTAL CHANGES IN THE WESTERN PART OF NORTHEAST PLAIN OF CHINA WESTERN DURING HOLOCENE

Two-three paleosol layers were formed in the western part of the Northeast Plain. China during Holocene. These paleosol layers interlaid with eolian fine sand layers. Dated by 14C dating. archeology and TL and analyzed by statistics.the formation periods of paleosols are divided from the results. The periods are 11, 000- 7000 5500-4500. 3500- 2800 and 1400- 1000 a B. P. respectively.According to the spore-pollen compositions in more than ten sand dune paleosol profiles, it is discovered th.t there is little spore-pollen in the sand layers and a little spore-pollen in the paleosol layers. The spore-pollen compositions in the paleosols are simple. mainly Artemisia (50% - 70%) and Chenopodiaceae. In the paleosols of 11,000 - 7000 a B. P.. the spore-pollen composition is Artemisia-Rubiaceaechenopodiaceae. The contents of Ephedra pollen in the lower and upper parts of the layer are less than that in the middle part. In the paleosols of 5500- 4500 a B. P.,the spore-pollen composition is Artem isal - Chenopod iaceae - Melilotus. There is some Salix sp. and Betula sp. pollen in the lower part of the layer and some Ephedra pollen in the upper part. In the paleosols of 3500- 2800 a B. P.. the spore-pollen composition is Artemisia Chenopodiaceae - Rubiaceae. There are som e Kochia and Baryaceae. In the paleosols of 1400-1000 a B. P., the spore-pollen composition is also Artemisia-Chjenopod tao eae - Rubiaceae. There is a little pine pollen. The grain size of paleosol is relatively coarse, but still finer than that of eolian sand and becomes coarser from the bottom to the top of the profile. This fact reflects that the weathering environments during the paleosol formation periods were wetter than that during the eolian periods and became dryer from middle to late Holocene.

Sandy desertification trend in western Northeast China Plain in the past 10 years

The west sandy land of the Northeast China Plain is located in the eastern huge sandy belt of mid-latitude in Eurasia and the eastern fringe of desertified land with best bio-climatic conditions in China. With rapid economic development, the deterioration of eco-environment has occurred and the desertification becomes very obvious. The first part of this paper studies the regional differences of landscape patterns and explores the regional differences of desertification. The second part aims to reveal the dynamics of desertification in the 1990s by using NOAA/AVHRR data and thematic data in GIS database. This work lays a scientific basis for the rehabilitation and development of the sandy lands.

东北平原西部沙地近10年的沙质荒漠化

东北平原西部沙地位于欧亚大陆中纬度巨型沙带的东部边缘 ,为我国沙质荒漠化土地的东缘 ,是我国自然环境最好的沙区。随着经济的发展 ,生态环境遭到严重破坏 ,沙质荒漠化景观日益明显 ,尤其是南部的科尔沁沙地 ,沙质荒漠化已十分严重 ,已经超过与其相邻的西部环境条件更差的沙区。利用 RS和 GIS,根据 NOAA/ AVHRR数据建立的沙质荒漠化监测指标 ,对东北平原西部沙地沙质荒漠化现代过程进行了动态监测 ,在此基础上利用 TM数据对沙质荒漠化的发展方式与成因进行了深入的探讨 。

东北平原西部沙地的气候变异与土地荒漠化

东北平原西部沙地位于欧亚大陆中纬度巨型沙带的东部边缘 ,为我国荒漠化土地的东缘。随着经济的发展 ,生态环境遭到严重破坏 ,荒漠化景观日益明显 ,前景令人堪忧。气候因素是荒漠化发展的一个基本因素 ,东北平原西部沙地是我国北方气候条件最好的沙区 ,但目前对于区域荒漠化驱动因子的气候因素影响方面的研究未开展系统的工作。论文系统分析了东北平原西部沙地影响荒漠化的现代气候因素特点 ,探讨了在较好气候条件下气候变异、人类活动与荒漠化之间的关系 ,并根据气候发展趋势预测了未来在自然因素作用下沙地的可能发展趋势。

东北平原西部沙地沙质荒漠化的遥感监测研究

东北平原西部沙地位于欧亚大陆中纬度巨型沙带的东部边缘 ,为我国沙质荒漠化土地的东缘 ,沙质荒漠化景观日益明显 ,前景令人勘忧。本文利用TM数据分析了区域荒漠化景观特征与土地荒漠化的特征 ,从机理上认识了区域的土地荒漠化发生过程 ;在此基础上以目前生态系统没有产生明显退化的生态状况作为基准 ,采用相对基准的办法 ,利用NOAA/AVHRR数据 ,确定了植被指数荒漠化监测指标 ;对荒漠化的动态变化及驱动因子进行了分析。研究认为区域荒漠化监测应当以全球常用多种分辨率的遥感数据为基础 ,在认识荒漠化发生机理之后进行监测与评估 ,在资料获取、分类分级和荒漠化监测的技术路线全球应有一个相对统一的标准 ,使评价的结果具有可比性。东北平原西部沙地的景观特征、沙质荒漠化程度、沙质荒漠化发展方式等具有明显的区域差异 ,二十世纪 90年代沙质荒漠化发展速度很快 ,但区域差异很大 ,这种区域差异与人口增长。

基于地貌特征的东北土地利用格局

采用Landsat TM7遥感影像和SRTM高程数据、东北土壤图等数据,应用GIS水文分析、空间分析方法和遥感影像监督分类方法对东北地区基本地貌类型和土地利用类型信息进行了量化。结果表明,大兴安岭山脊线以东、七老图山山地以北的东北区面积107.27万km2,分为山地、丘陵、台地、平原4种基本地貌,所占面积比例分别为21.2%、35.6%、16.1%和27.1%。明确了松嫩平原、松辽平原和科尔沁平原的位置、界线及相互关系,改进了传统的定性划分界线的方法。土地利用类型分为林地、草地、耕地、沙地、盐碱荒地、湿地滩涂、水域和建设用地,分别占41.1%、14.0%、33.8%、0.9%、1.5%、4.7%、1.4%和2.8%。最后讨论了土地利用与地貌相关的问题。