varves

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

可以树木年轮和被称为纹泥季节性沉积物进行计数来确定年龄。

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.

但纹层厚度变化可能揭示出沉积通量减少和上个世纪六十年代之后沉积通量增加。