环境演变研究时间序列的建立方法评述

对环境演变时间序列建立的几种主要方法的纪年原理、应用状况及应用的优点、范围、局限性进行了阐述和比较,包括长寿命宇宙成因核素在内的同位素纪年方法主要判别第四纪以来大时间尺主的沉积物的地质年龄,且能很好地应用于全球变化的研究,但百余年来沉积物的年龄及侵蚀历史变化的研究只能通过^210Pbex、^137Cs等半衰期相对较短的核素来进行;指出^210Pbex可望在现代流域侵蚀环境演变以及其效应评价的研究中获得新的突破。

Establishment of Time Sequence of Environmental Evolution

Progresses of several main dating approaches are reviewed, and the application advantages and limitations of these methods are also evaluated. Dating by isotopes that can give a longer life is usually used to establish the chronology of sediments, which were deposited during a very long period of time. This method can be successfully used in researches of global changes, but only 210 Pb and 137 Cs isotopes that have relatively short half lives can be used in dating sediments deposited during the last century and in studying erosion history. That 210 Pb has the potential to study contemporary fluvial erosion history is also proposed.