Era

Period

Age

Formation

Explanation

Cenozoic

Quaternary

Holocene-Pleistocene

Recent deposits

Alluvial sediments, valley, depression fill sediments.

Pleistocene

Habbariyia Gravel

sandy Gravel, Conglomerate

Tertiary

Late Miocene-Pliocene

Zahra Formation

Limestone, calcareous sandstones with hard recrystallized carbonates

Lutetian

Dammam Fn.

Fossiliferous limestone and dolomitic limestone alternations with clays chalky and cherty limestone

Danian

Um Erdhuma Fn.

Phosphatic limestone, dolomite, dolomitic limestone, and thin beds of anhydrite.

Mesozoic

Cretaceous

Late Maestrichtian

Tayarat Fn.

Limestone, yellow marl, dolomite, dolomitic limestone, and phosphatic siliceous limestone.

Late Campanian-Early Maestrichtian

Hartha Formation

Sandy limestone, dolomitic limestone and clayey dolostone interbedded with marly limestone

Turonian-early Campanian

Saadi Formation

Chalky Fossiliferous limestone, marly limestone and organic limestone.

Cenomanian-Turonian

Msad Formation

Coralline limestone, multi colored sandy dolostone, sandy marl and dolomitic limestone.

Cenomanian

Rutba Formation

Sandstones alternating with clayey silty sands, obtained coarse sands, and basal conglomerate.

Jurassic

Bathonian

Muhaywir Fn.

Dolomitic sandstone, fine ferruginous sands, limestone, marly limestone with conglomerate and cherty Clay.