A rhythmite consists of layers of sediment or sedimentary rock which are laid down with an obvious periodicity and regularity.
Of the many rhythmites found in the geological record, varves are among the most important and illuminating to studies of past climate change.
Geologic tidal rhythmites display layered Carboniferous Period beds which record tidal cyclical events such as semi-diurnal, diurnal or neap tide, spring tide cycle that demonstrate marine influence in sediments that were previously interpreted as purely continental.
[4] The Storm Mountain area of Big Cottonwood Canyon, Utah, has rhythmites which record sea-level sedimentary deposit fluctuations consistent with the cycle of the tides.
The regression and transgression of the sea level from waxing and waning glaciers have been identified in the rhythmites of the Pennsylvanian and Permian periods.