A varve is an annual layer of sediment or sedimentary rock. The word 'varve' is derived from the Swedish word varv whose meanings and connotations include 'revolution', 'in layers', and 'circle'. The term first appeared as Hvarfig lera (varved clay) on the first map produced by the Geological Survey of Sweden in 1862. Initially, varve was used to describe the separate components of annual layers in glacial lake sediments, but at the 1910 Geological Congress, the Swedish geologist Gerard De Gee… (More on Varve)