Tidal Rhythmites
First published: 2017
Brief summary
Reference on sedimentary deposits recording tidal cycles.
Article
Tidal rhythmites are sedimentary deposits containing repeated laminae produced by changing tidal currents. They commonly form where alternating periods of stronger and weaker flow cause systematic variations in sediment transport and deposition.
Individual laminae may reflect flood and ebb tides, while thicker groupings can record the difference between spring and neap tides. Spring tides occur near new and full moon, and neap tides occur near first and third quarter, producing a recurring modulation in current strength.
Measurements of lamina thickness and grouping can preserve daily, fortnightly, monthly and seasonal tidal signals. Ancient rhythmites have been used to investigate tidal dynamics and, in some cases, to estimate the number of days in an ancient month or year.
Interpretation requires careful separation of tidal signals from storms, river discharge and other depositional processes. Compaction, erosion, incomplete preservation and changes in sediment supply can modify the original rhythmic pattern.
Source details and credits
- Source / publisher: ScienceDirect Topics
- Source type: Reference article
- URL type: WWW
- Credits: ScienceDirect Topics
- URL: https://www.sciencedirect.com/topics/earth-and-planetary-sciences/tidal-rhythmite