大洋富钴结壳的年代学研究方法评述

富钴结壳被认为是目前最有潜在经济价值的海底矿产资源,又被视为良好的古海洋学记录,因此倍受关注。富钴结壳的年代学研究是目前结壳研究的难点和热点之一,Be同位素、U系放射性同位素、基岩年龄推算、生物地层学、经验公式计算、Sr同位素地层学、Os同位素地层学、磁性地层学等多种定年方法已经被广泛使用。虽然目前结壳定年的方法种类繁多,且各有优势,但没有任何一种方法能够以较高的精确度和可靠性以及简捷性给出富钴结壳的真实生长年龄,现阶段还需要采取多种方法综合研究给出较为精确的年龄。寻求新的、更为有效的定年方法很具必要性,因此较系统地总结近些年来富钴结壳年代学的研究进展和存在不足,对于指导以后的研究工作有着重要意义。

A REVIEW ON DATING METHODS OF OCEAN COBALT-RICH FERROMANGANESE CRUSTS

Cobalt-rich ferromanganese crusts are not only the important mineral resources,but also the potential paleoceanographic records,therefore,an increasing attention is paid to their research and application in recent years.Chronology of the ferromanganese crust is one of the difficulties involved in basic and theoretical geological research.Various methods have been used to date Fe-Mn crusts and nodules,such as Be isotope,uranium-series,calculation of substrate rock ages,biological stratigraphy,empirical equations using element concentrations,Sr isotope stratigraphy,Os isotope stratigraphy,magnetic stratigraphy and so on.Although there are a variety of methods,each of which has its advantages,there is no reliable method available to date a ferromanganese crust in a precise and convenient way.At present,a comprehensive study is also required on various methods for providing more precise ages,and it is necessary to find new,more effective methods.The principles,application fundamentals,qualifications and deficiencies of these different methods for dating ocean ferromanganese crusts have been summarized systematically in this review,which may benefits our study on Co-rich crusts in the future.