锶同位素研究在古季风演化研究中的应用研究

Application of strontium Isotopes in study on evolvement of East Asian summer monsoon

自从Rb-Sr同位素体系被应用于地质年龄以来,随着Rb-Sr同位素地球化学理论和测试分析技术的逐步发展和完善,其应用越来越广泛。主要介绍了锶同位素的基本地球化学特征,分析了锶同位素研究进行全球对比的可能性,探讨了锶同位素研究在我国黄土季风演化研究中的应用。众多研究显示Rb/Sr和87Sr/86Sr的比值变化受控于风化成壤作用的强弱,与降雨量、磁化率变化有很好的线性相关关系。通过曲线的分析、对比发现Rb/Sr和87Sr/86Sr曲线所蕴含的气候信息比磁化率曲线更为丰富和详细,与SPECMAPδ18O曲线具有同步变化特征和更好的对应关系。这些研究表明Rb/Sr和87Sr/86Sr比值极可能是一种东亚夏季风演化更为灵敏的替代性指标,在古气候重建中有着广阔的应用前景。

With the development of Rb-Sr istopic system geochemical theory and the improvement of analytical and testing techniques,strontium isotopes have been widely applied in many fields of Earth Science. This article not only introduces geochemical characters of strontium and analyzes the possibility of its application in the contrast of the global climates,but also discusses the application of strontium isotopes in the East Asian summer monsoon. Many studies show that the changes of Rb/Sr and ^(87)Sr/^(86)Sr ratios are influenced by the intensity of weathering and pedogenesis. Furthermore, Rb/Sr and ^(87)Sr/^(86)Sr ratios have good linear mutuality with the changes of preciptation and magnetic susceptibility. Rb/Sr and ^(87)Sr/^(86)Sr curves embody more climate information and coincide with SPECMAP δ^(18)O curve better than magnetic susceptibility curve via curves contrasting and analyzing. All these studies indicate the Rb/Sr and ^(87)Sr/^(86)Sr ratios in loess-paleosol sequences may be an excellent and sensitive proxy of the East Asian summer monsoon, and have potential importance in reconstructing history of the palaeo-climate.