地理科学 ›› 1996, Vol. 16 ›› Issue (4): 345-350.doi: 10.13249/j.cnki.sgs.1996.04.345

• 论文 • 上一篇    下一篇

贵州红枫湖纹理沉积物中近代气温记录

吴丰昌, 万国江, 黄荣贵   

  1. 中国科学院地球化学研究所环境地球化学国家重点实验室, 贵阳550002
  • 收稿日期:1995-08-04 修回日期:1996-02-28 出版日期:1996-07-20 发布日期:1996-07-20
  • 基金资助:
    国家自然科学基金资助项目

RECENT TEMPERATURE RECORDS OF ANNUALLY LAMINATED SEDIMENTS IN HONGFENG LAKE, GUIZHOU

Wu Fengchang, Wan Guojiang, Huang Ronggui   

  1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Academica Sinica, Guiyang 550002
  • Received:1995-08-04 Revised:1996-02-28 Online:1996-07-20 Published:1996-07-20

摘要: 本文通过红枫湖纹理沉积物柱芯碳酸盐特征剖面与流域气温资料对比、沉积纹理年代校正以及早期成岩化学过程对碳酸盐沉积记录的改造作用等方面的研究,表明湖泊碳酸盐沉积记录基本不受早期成岩作用的影响,碳酸钙含量和CaO/MgO·Al2O3比值可作为湖泊沉积物中具高分辨率、短时间尺度的气温变化的代用指标.

Abstract: Lake sedimentation is a large pool for past global change. Carbonate geochemistry as an index has interested many scien-tists, and can provide a variety of high-solution information on short-or long-term climatic or environmental changes.Through detail comparison of profile of carbonate concentration and CaO/MgO·Al2O3 ratio in the core which is calibrated according to mass-depth from varve-counting dating with recent annual average temperature data we find that the agreement between the two cuvyes is astonishingly good, meanwhile, average molal ratio of CaO and CO2 in the sediments is nearly 1:1, this suggests that almost all carbonate minerals are calcite, which contains many climatic and hydro chemical information. They probably refect the relationship between calcite precipitation and climate change.According to calcite phychemical equibrium of pore water at the sediment-water interface during early diagensis process, we calcuate the Fd(carborate loss flux due to dissolution and upward diffusion at the interface)and Fs(calcite sedimentary flux). We define r as carborate perturbative extent at the interface:
r= Fd/Fs(1)
r is about 17%, we, therefore, can conclude that calcite unsaturated dissolution and perturbative process at the sediment-wa-ter interface is very small, much smaller than we imagine before.The paper finally suggests that carbonate concentration and CaO/MgO·Al2O3 ratio can be used as a high-solution temper-ature index in recent lake sediments.