非传统稳定同位素锶(δ^(88/86)Sr)的地球化学研究进展

Advances in Applications of Non-traditional Stable Strontium(δ^(88/86)Sr) Isotope in Geochemistry

锶有4个稳定同位素:84Sr、86Sr、87Sr和88Sr。但其中的非传统稳定同位素(δ88/86Sr)成为近年来国际同位素地球化学领域的研究热点。本文根据国际众多学者的研究,阐述了大多数实验室新近采用双稀释剂和TIMS方法来获得高精度δ88/86Sr数据的原理,并综述自然界δ88/86Sr变化,列出一些影响锶同位素分馏的因素。综合讨论其在地质方面的应用:(1)根据冷水珊瑚稳定锶同位素重建古海洋温度;(2)联立87Sr/86Sr和δ88/86Sr来研究海洋中锶的地球化学循环;(3)利用骨骼中的锶稳定同位素研究古营养学。

Stable strontium isotope,one of the non-traditional stable isotopes,has been focused on in isotope geochemistry since last ten years and has become one of the exciting frontier sciences in geo-scientific studies.Strontium has four stable isotopes:84Sr,86Sr,87Sr and 88Sr.TIMS or MC-ICP-MS can be employed to measure stable strontium isotopes,and the ratios are expressed as δ88/86Sr.Variations in δ88/86Sr in nature range from-1.73‰ to 0.66‰.The factors affecting strontium fractionation are indistinct,and more work needs to be done on the fractionation mechanism for further understanding.At present the applications of stable strontium isotope geochemistry are presented as follows:(1) Paleoceanographic temperaure reconstruction based on δ88/86Sr of cold-water corals;(2) combining radiogenic strontium and stable strontium fractionation to study geochemical cycling in the ocean;(3) paleodietary research with stable strontium in bones.