- Group(s): Glaciers - Key Terms
Varves are successive layers of fine sediments deposited by meltwater streams into glacial lakes. During the summer months when discharge is higher, more sediments flow into the lake and deposits accumulate more rapidly. Coarse material in particular, such as sand and silt, flows into the lake during the summer melt and is deposited on the lake bed. During the winter where there is little or no discharge in meltwater streams, finer material and organic matter within the lake will sink to the bottom. This gives a distinct series of layers to the sediment. The two varves from the winter and summer deposition represents a year of the glacial lake’s history. Studying the subsequent layering that occurred after the original deposition can enable glaciologists to study the lake as they would study the rings of a tree to build up an interpretation of past climatic conditions.