Tidal Dominated

Summary

Tidal dominated environments are part of the marine shore, being constantly exposed and submerged by falling and rising tides. Tidal flats will form within estuaries, bays, barrier-islands, deltas, and other coastal areas protected by waves. Tides are cyclical, they will rise until high tide is reached, then fall until low tide is reached. This cyclical rising and falling of the tides at least once per day, sometimes twice. The speeds of tides can vary greatly, depending mainly on geography (Vakarelov et al,. 2012).  Tidal dominated shelves are found on along some portions of continental shelf (Boggs, 2014). There are different tidal ranges, microtidal that are <6ft, and mesotidal between 6-12ft. The constant change in flow direction often leaves evidence of two distinct transport directions in rock. Both ripple lamination and dune cross-stratification are common is tidally dominated environments (Eidam et al,. 2016). This bimodal movement of sediment will produce a distinct sedimentary structure called herringbone cross-stratification. If one flow direction is more dominant than the other, a structure called reactivation surfaces will appear. This is an erosional surface that cuts away the set of cross-stratified structures. Mud drapes are another common structure, the form during especially high or low tides when water are calm enough to allow fine-grained sediments to fall out of suspension. They create a layer above the sand which, due to the relatively high cohesion of mud, is more resistant to erosion (Longhitano et al,. 2012).