Rhythmite

A rhythmite consists of layers of sediment or sedimentary rock which are laid down with an obvious periodicity and regularity. They may be created by annual processes such as seasonally varying deposits reflecting variations in the runoff cycle, by shorter term processes such as tides, or by longer term processes such as periodic floods.

Rhythmites serve a significant role in unraveling prehistoric events, providing insights into sea level change, glaciation change, and earth's orbital variations which serve to answer questions about climate change.

Annually laminated rhythmites

Annually laminated deposits or varves are rhythmites with annual periodicity: annual layers of sediment or sedimentary rock are laid down through seasonal variations that result from precipitation, or from temperature, which influences precipitation rates and debris loads in runoff. Of the many rhythmites found in the geological record, varves are among the most important and illuminating to studies of past climate change. Varves are amongst the finest resolution events easily recognised in stratigraphy.