海洋环境中的锇同位素研究现状

由于锇同位素示踪和定年具有较高的灵敏度，能提供其它同位素无法给出的重要信息，在海洋环境中应用具有独特的优越性，因此锇同位素在海洋环境中的的研究和应用引起了人们的广泛关注。近年来，国内外学者对海洋环境中的锇同位素研究取得了较大的成果，主要体现在以下几个方面：①对富钴结壳、海底铁锰结核、富有机质沉积物、富金属碳酸盐和深海远洋粘土中的锇同位素组成进行了较多研究；②对海水中锇的浓度、滞留时间，以及现代海水的锇同位素组成进行了精确测定；③初步建立了过去80Ma以来海水锇同位素组成的演化曲线；④对深海橄榄岩、大洋玄武岩、俯冲带岩石和大洋中脊喷出的热液流体的锇同位素组成进行了研究；⑤探讨了海洋环境中影响海水锇同位素组成变化的制约因素，初步揭示了海洋环境中的锇同位素组成对古海洋、古气候和古地理的指示意义。较系统地总结近年来锇同位素在海洋环境中的研究现状，对于指导以后的研究工作有着重要的意义。

PROGRESS OF RESEARCH ON OSMIUM ISOTOPE IN MARINE ENVIRONMENT

Os isotope possesses the higher sensitivity in dating and tracing in marine environment in comparison with other isotopes, and can provide some important information that other isotopes cannot give. Therefore, an increasing attention has been paid to the application of Os isotope in marine sciences in recent years. Some important progresses of the Os isotope application in this aspect are summarized as follows: Firstly, Os isotope composition of Co-rich crust, ferromanganese nodule, organic rich marine sediments, metalliferous carbonates and pelagic clay had been determined by many researchers. Secondly, the Os concentration and residence time in seawater, and Os isotope composition of seawater were precisely measured. Thirdly, the evolution curve of the Os isotopic composition in seawater over the past 80 million years has been roughly constructed. Fourthly, the Osmium isotope composition of the abyssal peridotites, oceanic basalts, rocks in subduction zones and hydrothermal fluids from the Mid Ocean ridge had been determined. Finally, the constraint factors on the Os isotope composition of seawater were systematically discussed, and some significant implications of the Os isotope compositions in the marine environment for palaeoceanography, palaeoclimatology and palaeogeography had been revealed. The progresses of Os isotope in the marine environment in recent years have been summarized in this review, which may benefits our study on Os isotope in the future.