Paleosandstorm characteristics and lake evolution history deduced from investigation on lacustrine s

来源 :Chinese Science Bulletin | 被引量 : 0次 | 上传用户:dianshenshizhe
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Sediment cores from desert lakes serve as good records of the frequency and intensity of sandstorms in his- tory. By multi-proxy analysis of grain-size, magnetic suscep- tibility, TOC and Rb/Sr ratio, the paleosandstorm character- istics and lake evolution history in Yulin Area for the past 80 years. are discussed in this article. It is revealed that Hong- jiannao Lake formed in about 1928 A.D. and in its initial stage sandstorms were prevalent with three extremes taking place in 1936 A.D., 1939 A.D. and 1941 A.D.. During the ex- pansion period of 1952―1960 A.D., inflow waters to the lake increased sharply and a lot more weathered materials were carried into the lake. The frequency and intensity of sand- storms have reduced a lot since 1960s and the “double peaks” feature of the grain-size frequency curve has changed into the “single peak” feature. Study on the catchment ecol- ogy of the lake shows that the occurrence of sandstorms has been effectively restrained by the forest plantation and water and soil conservation. Sediment cores from desert lakes serve as good records of the frequency and intensity of sandstorms in his- tory. By multi-proxy analysis of grain-size, magnetic suscep- tibility, TOC and Rb / Sr ratio, the paleosandstorm character- istics and lake are discussed in this article. It is revealed that Hong- jiannao Lake formed in about 1928 AD and in its initial stage sandstorms were prevalent with three extremes taking place in 1936 AD, 1939 AD and 1941 AD. During the exponential period of 1952-1960 AD, inflow waters to the lake increased sharply and a lot more weathered materials were carried into the lake. The frequency and intensity of sand-storms have reduced a lot since 1960s and the “Double peaks” feature of the grain-size frequency curve has changed into the “single peak” feature. Study on the catchment ecol- ogy of the lake shows that the occurrence of sandstorms has been effectively restrained by the fores t plantation and water and soil conservation.
其他文献
南朝鲜从一个穷国一跃发展成为引人注目的亚洲“四小龙”里的一员,仅用了短短的20余年时间。其主要原因之一,便是它成功地实施了外向型经济发展战略,劳务输出是其中的重要一
三峡▽85系统砂石廊道模板采用了一种简易的三铰门式台车结构,在实际运用中取得了一些成功的经验。三铰门式台车具有用料省,结构简单,可操作性好等特点,能够确保质量,加快速
我国2000年化肥进口政策原则是对化肥进口仍实行严格的管理制度,严格执行化肥代理制度,严禁越权进口。化肥进口配额由国家经贸委和外经贸部联合下达。2000年化肥进口对总量
国画大师齐白石用他的生花妙笔为世人创作了大量弥足珍贵的艺术精品。这位经历了将近一个世纪的世界文化名人,留下了太多的故事,太多的传说,关于他生平事迹的文字资料浩如烟
去年以来,国际市场化肥价格特别是磷酸二铵价格变化较大,为了使进口化肥价格管理适应市场形势变化,近期国家计委下文决定进一步改进中央进口化肥价格管理办法,现将有关事项
2016年10月,第二十届中国少儿戏曲小梅花荟萃活动在浙江嵊州举办。这次活动历时5天,共演出10场,有近200个节目在舞台上亮相。展示的项目包括:京剧·昆曲片断、唱段演唱,地方
作好准备迎接南水北调水利部南水北调办公室副总工程师谢金荣北京水利学会水利经济研究会副主任1南水北调的水来之不易南水北调中线工程从湖北丹江口水库引水,沿京广铁路线两侧
丹江口大坝加高试验达到初期工程设计高程1996年6月1日丹江口水利枢纽管理局召开丹江口大坝加高第二次新老混凝土结合现场试验施工(阶段)总结会,丹江口大坝新老混凝土结合第二次试验,已
实施:在1994年结束的乌拉圭回合期间商定的协议的执行情况。发展中国家要求进行回顾,看看协议是否得到实施。这是争议最多的问题之一。总务委员会:世贸组织在部长级会议以外的执行委
公交模型的核心是公交OD矩阵,传统一般通过跟车问卷调查获取公交OD,该方法投入大而精度低。为提高公交OD质量并节约投入,本文运用日益推广的智能公交新技术,包括视频监控技术