[关键词]
[摘要]
为了探索沉积速率与降水之间的相关关系, 通过实验测出勐统河流域出口河漫滩沉积物剖面中210 Pb 的比活 度, 并采用CRS( Constant Rate of 210 Pb Supply) 模型对沉积物进行计年, 分析了20 世纪50 年代以来流域出口沉积 物的沉积速率。210 Pbex 剖面分布中的两个特殊沉积点分别对应2002 年和1980 年, 结合该流域同期的多年降水量分 布情况, 发现两个特殊沉积点与1970 年到1980 年及2002 年左右的强降水密切相关。根据CRS 模型计算得出流 域出口的沉积速率从20 世纪50 年代开始一直呈现增长的趋势, 这可能与流域内强烈的人类活动( 森林砍伐和不合 理的土地利用) 有关。
[Key word]
[Abstract]
In or der t o study the r elationship between the sedimentation rat e and pr ecipitation, the specific act ivity of 210 Pb o f the floo dplain sediments in the o ut let of Mengto ng water shed was measured by the gamma spectr ometr y. The ag e o f sediment s w as calculated using the CRS( Constant Rate of 210 Pb Supply) model, and the sediment ation rate w as analyzed since t he 1950s. Tw o special sediment po ints w ith high 210 Pb activity w ere dated at 2002 and 1980, respect ively, and t hey had str ong r elatio nship with the precipit ation from 1970 to 1980 and in 2002. Sedimentat ion r ate incr eased g reatly from the 1950s determined by the CRS model, w hich may be caused by the intense human activit ies( cutt ing tr ees and unreasonable land use) in the w atershed.
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[基金项目]
国家重点实验室开放基金( SKLH2 0F21202) ; 国家自然科学基金( 41271045) ; 博士点基金( 20130181110045)