湖泊化学碳酸盐与生物碳酸盐氧同位素组成差异的环境意义

Environmental Significance of Oxygen Isotopic Composition Disparity between Co-existing Biogentic and Inorganical Carbonate Minerals

中文关键词:  化学碳酸盐  生物碳酸盐  氧同位素  方解石

英文关键词:Inorganic carbonate  Biogentic carbonate  Oxygen isotope  Calcite

中文摘要:

      湖泊生物碳酸盐形成于湖水底层,化学碳酸盐形成于湖水表层；处于湖积物同一层位的两种成因类型的碳酸盐氧同位素组成(δ¹⁸O)差异可能反映了二者形成时的环境差异,如湖泊不同深度的水温差异、碳酸盐质生物如介形类小生境水体δ¹⁸O值、两种成因碳酸盐形成的时间先后、湖泊表层水体蒸发情况等。在进行碳酸盐δ¹⁸O环境意义分析时,应分开测试生物碳酸盐和化学碳酸盐δ¹⁸O。

英文摘要:

      :The research results of Qinghai lake,Siling lake,palaeo-lake Zoige,and lake Zurich,indicate that the oxygen isotopic differences between co-existing benthic ostracods living on the lake bottom,and inorganical carbonate precipitated at the water surface,with the latter more negative,may be explained by the different water temperature,their seasonal difference in formation time,δ¹⁸O of bottom water microenvironment where ostracods live in,and the evaporation of water surface.The testing of single carbonate mineral δ¹⁸O becomes the best choice whilst using carbonate δ¹⁸O as one of the environment proxies for the study of regional climatic evolution.