A sedimentary model of tidal sand bars in an estuarine environment is established.

Early aggregates of ferrous clay precursors were emplaced in tidal sand bar at the end of 3rd order transgressive cycle.

Chloritization occurs after mechanical compaction or at the beginning of the chemical compaction.

Cathodoluminescence microscopy and δ¹⁸O of quartz overgrowths indicate two silicification stages.

Chlorite coating preserves porosity and permeability.