A vocabulary of landscape — a landscape of words
1083 entries
varve
A varve is a pair of sediment layers deposited in one year in a still body of water: a coarse pale layer laid down in summer when meltwater carries silt in and a fine dark layer that settles through the winter when the surface is frozen and the water is calm. Counted downward, varves give an exact year count, and a sequence can run to thousands of years.
Etymology
The word is Swedish for a layer or a turn, and it came into English through the work of Gerard De Geer, who counted varves in Swedish glacial lake clays from the 1880s and used them to build a chronology for the retreat of the ice sheet. He established a timeline in calendar years long before radiocarbon dating existed.
Notes
Varved sequences are among the very few natural archives that give an absolute year count rather than an estimate, alongside tree rings and layered ice, and they are used to calibrate the others. The best sequences come from lakes that are deep, sheltered, and free of burrowing animals, which is why maar lakes are such valuable sites: steep-sided, small, and undisturbed on the bottom.