Varve

Part of speech: noun

Pronunciation: /vɑːv/

Definitions

1. A geological term describing alternating layers of sediment that accumulate in bodies of water, revealing seasonal patterns and fluctuations over time
2. This refers to a specific type of sedimentary sequence characterized by annual variations in particle size and composition that reflect environmental conditions
3. A sedimentary feature consisting of yearly layers that indicate changes in deposition related to seasonal variations and climatic conditions

Etymology: "Varve" reaches English from Swedish, where "varv" originally meant a layer or a turn, as in one revolution of a wheel or a round of something. The word was adopted by geologists to describe the thin, paired layers of sediment laid down in lakes, most often one pale layer deposited in summer and one dark layer in winter. Counting these layers lets researchers read a lake bed much like tree rings, with each pair marking a single year. The sense of a repeated cycle sits at the heart of the Swedish word, which is why it suited the phenomenon so well. A single varve is a record of one season's sedimentation, and a long sequence of them preserves a dated archive of climate and runoff conditions stretching back thousands of years in some lakes.