摘要
内陆湖泊沉积物的易溶盐含量与湖水的化学组成密切相关 ,通过测试沉积物 (岩心 )的易溶盐含量可以重建古湖水化学演化过程。在安固里淖湖心区钻取沉积剖面 ,以 1cm为间隔分样 ,测试剖面中八大离子的含量 (即K+ 、Na+ 、Ca2 + 、Mg2 + 、CO32 - 、HCO3- 、Cl- 和SO4 2 - )和其他有关的地球化学特征 ,并且对各项离子含量进行相关分析 ,得到剖面易溶盐组成变化曲线和易溶盐指标变化曲线。根据易溶盐曲线变化情况 ,结合岩心纹层纪年得到的纹层年代 ,将安固里淖 850 7aBP以来的湖水化学演化过程分为以下几个阶段 :850 7～ 76 0 0aBP ,湖水化学类型为Na+ -Cl- 型 ,盐度较高 ;76 0 0～ 4 72 4aBP ,湖水化学类型为Na+ -Cl- -SO4 2 - 型 ,盐度最高 ;4 72 4～ 30 57aBP ,湖水化学类型为Na+ -Cl- 型 ;30 57～ 574aBP ,湖水化学类型为Na+ -CO32 - -HCO3- 型 ,盐度较低 ;574aBP以来 ,湖水化学类型为Na+ -Cl- 型 ,盐度较低但呈现快速增加趋势。同岩心的粒度分析结果相比较 ,易溶盐变化曲线的转折早于粒度变化曲线 ,反映易溶盐沉积对气候变化的反应比粒度特征更敏感 ,是一个较好的反映气候变化的替代性指标 ,有待于推广应用。
The distribution of soluble salt sediments of in_land lake is closely related with the hydrochemical feature of lake water, so the process of hydrochemical evolution of the lake can be reconstructed by analyzing the lake's soluble salt sediments. Through coring in the lacuster of Angulinao Lake, testing the eight kinds of ions( K +、Na +、Ca 2+ 、Mg 2+ 、 CO 3 2- 、 HCO 3 -、Cl - and SO 4 2- ) and other related geochemical features, and analyzing the correlation among the ions, the curves of soluble salt distribution and soluble salt indictors have been drawn. According to the variation of curves of soluble salt, and combining with the varve chronology, the hydrochemical evolution of Angulinao Lake is speculated from the soluble salt distribution of the core: During 8507～7600 a BP, the lake was abundant in Na + and Cl -,and its saltness was high; in 7600～4724 a BP, the water was abundant in Na +, Cl - and SO 4 2- , its saltness was very high; in 4724～3057 a BP,the water was abundant in Na + and Cl -;in 3057～574 a BP, the water was abundant in Na +, CO 3 2- and HCO 3 -, its saltness was a little low; since 574 a BP, the lake was abundant in Na + and Cl -, the saltness was low and going up. Comparing with the curves of grain size, the turning points of curves of soluble salt are earlier than curves of grain size, therefore the soluble salt sediments are more sensible to fluctuation of environment and are good indictors. It should be extended to apply.
出处
《古地理学报》
CAS
CSCD
2001年第1期91-96,共6页
Journal of Palaeogeography：Chinese Edition
基金
国家自然科学基金资助项目 (批准号 :494710 6 7)
关键词
全新世
易溶盐
沉积
环境变化
安固里淖
Holocene, Angulinao Lake, soluble salt, environment change
