【摘要】 本文通过岩性、粒度、磁化率、有机碳、化学元素的多指标综合分析,对陕西红碱淖近百年以来的环境演化进行了探讨。红碱淖于1927年后开始成湖,以较低的磁化率值、低湖泊生产力和较高的Fe/Mn比值为特征;1952-1960年,为短暂湖泊快速扩张时期,在沉积物中表现为粘粒含量一度下降、各元素浓度明显被稀释;自1960年以来,岩性和指标特征反映了该湖演化为稳定的深湖环境。湖泊的形成和扩张与区域降水量的增加有关,而50年代后期以来湖面的迅速扩大同时得益于人类滩地疏导导致的入湖水量增加。人类活动也引起了近40年来湖泊生产力的提高和沉积物-水界面氧系统的变化。此外,钻孔粒度特征较好地分辨出20世纪30年代末至40年代3次强沙尘暴事件。更多还原

【Abstract】 The environment evolution in the past nearly 100 years was revealed by the multi--proxy analysisof lithology, grain size, magnetic susceptibility, TOC and geochemical elements from the Core Hin Hongjiannao Lake, Shaanxi Province. The result indicates that Hongjiannao Lake was formed atabout 1927 AD, characterised by a relatively higher value of Fe/Mn ratio and a lower level of lakeproductivity and magnetic susceptibility value. During the span between 1952 and 1960, the lakelevel rose remarkably, as shown by the sharp decrease of clay fraction and the obvious dilutioneffect on the geochemical elements concentration in sediment. The lithologic character and sedi-ment proxies reflect that the lake has developed into a stable deep--water condition since 1960. Thelake formation and its subsequent rapid expansion in the late 1950s related closely to the regionalrainfall increases, and the latter also benefited from extensive reclamation of the lowland aroundthe lake. Human activities have also resulted in the higher lake production and the changing ofredox condition on sediment--water interface in the recent 40 years. Moreover, the 3 strong duststorm events happened in the late 1930s and 1940s were well distinguished in terms of the featuresof grain size frequency distributions in the sediment core.更多还原