碎屑白云母^(40)Ar-^(39)Ar示踪及在长江贯通研究中的应用探讨

^(40)Ar-^(39)Ar Age Tracing of Detrital Muscovites and Its Application in Yangtze River Running-Through Time

使用碎屑白云母40Ar-39Ar年代学示踪方法研究长江贯通是一种新探索。在分析这一方法示踪的基本原理之后,讨论了碎屑白云母40Ar-39Ar年代学方法在判别沉积物物源、研究水系演化和计算源区剥蚀速率等方面的一些应用,然后从取样位置的选择、样品的采集与处理以及上游源区白云母40Ar-39Ar年龄分布等方面就这一方法应用于长江贯通研究的可行性进行了探讨。研究这一问题的思路是:先整理源区白云母40Ar-39Ar年龄分布,再分析盆地沉积物中碎屑白云母年龄分布在垂向的变化,最后对比这两种年龄分布的关系来制约长江贯通时间。

It is a new way to use 40Ar-39Ar thermochronology of detrital muscovites to research the development of the Yangtze River.After introducing the basic principle of 40Ar-39Ar thermochronology of detrital muscovites in provenance analysis,the paper discusses the major applications of this method to determine sediment source regions,reconstruction palaeodrainage system,estimate erosion rates for modern sedimentary catchments,etc.Then it analyses the possibility of using this way to research the evolution of Yangtze River from the selection of sample positions,samples collection and distribution of 40Ar-39Ar age of muscovite in the Yangtze River Basin.Finally,it presents the ideal study of the evolution of the river： the comparison of the distribution of vertical variation of detrital muscovite 40Ar-39Ar ages in sedimentary basin with 40Ar-39Ar age of muscovite in source region of Yangtze River Basin followed by the determination of the running-through time of the river.