Tree rings and seasonal sedimentary deposits called varves can be counted to determine absolute age.

可以对树木的年轮和被称为的季节性沉积物进行计数来确定其绝对年龄。

The variation of varve thickness may show a decrease of sediment flux during the Little Ice Age, and an increase of sediment flux after 1960s.

但层厚度的化可能揭示出小冰期沉积通量的减少和上个世纪六十年代之后沉积通量的增加。