The post Abu Dabbab Evaporite Upper Miocene (?) Pliocene sediments along the Red Sea coastal area south and north of Mersa Alam could be subdivided into three lithofacies: Facies A : Dominantly fluviatile siliciclastics, with restricted marine carbonates and evaporites near the top (samh Mb. of Mersa Alam fm.). Facies B: Open Marine, mixed siliciclastic-carbonate sediments deposited in beach, intertidal to very shallow subtidal, and less commonly aeolian environments (Gabir Mb. of Mersa Alam Fm. and Shagra Fm.). Facies C: Sea marginal, coarse siliciclastic, fans with minor carrbonates, unconformably overlying Facies " C" or Facies " A" (Samadai Formation).
Synsedimentary tectonics played a great role in the distribution of these facies. Thus by Late Miocene-Early Pliocene (?), rejuvination of older ENE faults and shears created NE trending depressions and highs. Facies "A" was deposited on both the highs and lows but with thicker siliciclastics in the lows.
By Early Pliocene the late rifting event initiated rejuvination along NW trending faults., resulting in more tilting of the faulted blocks, thus giving rise to new highs and lows of NW orientation which controlled the deposition of Facies "B" and "C"