【摘要】 在湖泊沉积与环境演变研究中,粒度参数通常用来反映湖泊水动力条件的变化,进而反映湖面波动状况以及湖区环境有效湿度的变化．镜泊湖JPH-1钻孔沉积物粒度分析表明:全新世以来镜泊湖沉积物粒度的变化呈现明显的粗细交替变化的规律性．结合14C测年,镜泊湖沉积物粒度特征有效地指示了历史时期镜泊湖水动力变化的情况．进而揭示了该地区古降水的变化历史．9300-8540cal aBP,是一个降水较少的偏干旱时期;8540-6350 cal aBP,降水颇丰的湿润时期; 6350-3120cal aBF,气候波动频繁,前期(6350-4800 cal aBP)由湿润向干旱过渡,后期(4800-3120cal aBP左右)又由于早转向湿润,31 20-1 580 cal aBP,降水较多,气候湿润;1 580 cal aBP至今,降水变化波动剧烈,这阶段粒度特征的变化除了与降水的自然变化有关外,还与人类活动的剧烈影响有关系．湖区周围人类活动破坏了原始植被,大量地表裸露,降水冲刷地表作用明显增大,陆源物质被携带人湖,粗颗粒含量显著增多．更多还原

【Abstract】 Grain-size composition of lacustrine sediment is a powerful indicator to water impetus change and humid variation in the history. Based on the analyses on the grain-size composition characteristics of JPH-1 core , from Lake Jingpo, northeastern of China, combined with C age sequence, the Holocene history of paleo-precipitation changes in this region can be concluded as below; ( 1 )9300 -8540 cal aBP was a relatively dry period accompanied with less precipitation. (2) 8540 -6350 cal aBP was a high lake level period, when the precipitation was relatively abundanto. (3) 6350 -4800 cal aBP, the climate became drought gradually. (4) 4800 -3120 cal aBP, the climate changed wet again. (5) 3120 - 1580 cal aBP was a relatively stable period maintained a high lake level with abundant precipitation. (6) 1580 cal aBP-present, it was an another climatically oscillation period in which the precipitation has been changing frequently. In recent centuries, the human activities, such as clearing the forest, destroying the original vegetation in lake watershed resulted in massive exposure of land surface, remarkable increase of erosion and more terrestrial materiel carried into lake. Therefore, the portion of coarser particles increased markedly.更多还原