Tidal flat
Depth of water
High tide - Ebb tide
Circumstances
Formed at the tidal zones at the inner bays and inner lagoons where the differeces of tidal level are large. Subjected to the little influences of waves. Sands are supplied during rising and pulling tides, and mud is supplied during the slack water such as high tide. 2 pairs of sand an mud beds corresponds to the 2 tides in a day. Tides in the tidal flats flow in the tidal channels.
Sedimentary facies (Sediments)
Finely interbedded sands and mud. Massive fine sands and massive silt.
Sedimentary facies (Sediments, Reef)
Lime-mudstone, Dolo-mudstone, Bioclastic wackestone, Bioclastic packstone, Peloidal grainstone, Dolomite
Sedimentary facies (Structures)
No graded bedding by the strong bio-turbation. Double mud drapes in sandstones. Wave ripples. Cross stratifications associated with mud drapes and herringbone cross-stratifications in tidal channels.
Facies fossils
Trace fossils of crabs such as Ocypodidae
Sedimentary systems
Components of shallow marine systems
- Beach ridge
- Interbarnal lowland (Ridge)
- Eolian dune
- Interdune lowland
- Salt marsh
- Backshore
- Foreshore
- Tidal flat
- Tidal channel
- Beach rock
- Lagoon
- Flood tidal delta
- Washover fan
- Upper shoreface
- Barrier island
- Sand spit, Longshore bar
- Ebb tidal delta
- Lower shoreface
- Inner shelf
- Outer shelf
- Sand wave
- Sand ridge
- Tsunami
- Transgressive lag