The stratigraphic succession of rock layers beneath the desert surface of Kuwait is divided into five groups ranging in age from Holocene (less than 2 million years) to Lower Cretaceous (less than 144 million years). These are, from youngest to oldest: Kuwait, Hasa, Aruma, Wasia and Thamama. The dominant lithology is sand, limestone, gravel, shales, clays and evaporites. The stratigraphic column of Kuwait is dominated by the stable shelf conditions of the Arabian crustal plate since the Paleozoic (245 to 570 million years) and the early Mesozoic Periods (less than 245 million years old), causing the deposition of a thick sequence of shallow water sediments and evaporites. Within Early Miocene time (less than 24 million years old) a peripheral basin formed at the northwest side of the Zagros belt, covering the northwest part of the Arabian Gulf and the Arabian Peninsula. Continental clastics shed from the east and west highlands filled the shallow basin, forming the upper Tertiary sequence of Miocene to Pleistocene age.

The Kuwait Group, which ranges in age from Miocene to Pleistocene (less than 24 million years old), represents a sequence of clastic sediments 150 meters in thickness. It may be divided into three formations. These are, from top to bottom: Dibdibah, Lower Fars and Ghar Formations, which were described earlier. The degree of cementation varies with depth. Most are cemented with evaporites and carbonates. The environment of deposition is continental and evaporitic with shallow marine components. Lenses of fresh water were found within the Kuwait Group, such as Ar- Raudhatain and Umm Al-Aish fields.

The Hasa Group from top to bottom consists of: Dammam, Rus and Umm Radhuma, ranging in age from Middle Eocene to Paleocene (47-67 million years). An erosional unconformity separates the Kuwait Group from the Hasa Group. This unconformity is represented in the basal clay or cherty layers of varying thickness.

The Hasa Group has a wide extent from Saudi Arabia through Kuwait and Iraq to Iran. The Dammam Formation underlies the whole of Kuwait and averages 250 meters in thickness. It consists mainly of shaly and chalky limestone with cherts, anhydrites and dolomites. During the Middle Eocene epoch (about 18 million years) an invasion of fresher water brought about the widespread deposition of carbonates. The depositional environment was probably shallow marine grading into continental conditions. Brackish water in large quantities was found within the Dammam Formation, which is highly karstified at several depths in the southwest corner of Kuwait. The oldest exposed outcrop in Kuwait is of the Dammam limestone, which is Middle Eocene in age (about 47 million years), and is uncomfortably overlain by the terrigenous sequence of Kuwait Group deposits. It outcrops in a small area in the southern part of Kuwait which may be related to the regional structure of Kuwait.

The most common surface deposits associated with the Dammam Formation and Kuwait Group in general is the "Gatch Layer". This is sand highly cemented with salt, i.e., calcrete cemented with calcite and gypcrete cemented with gypsum.

The oil reservoirs are concentrated in the Aruma, Wasia and Thamama Groups of the Cretaceous System (67-144 million years), which varies in thickness from about 2,070 meters in southeast Kuwait to about 3,450 meters in north -west Kuwait. The lithology is predominantly limestone and subordinate shale, with two major oil-bearing sandstone formations in the Lower and Middle Cretaceous.

These are the Zubair Formation, which is approximately 450 meters thick, and the Burqan Formation, which is approximately 380 meters thick. Other oil producing formations are the Ahmadi, Wara, Mauddud, Zubair, Ratawi and Manaqish.

Quaternary and Tertiary gravels of igneous and metamorphic origin cover most of Kuwait's desert surface. These were deposited during a fluvial stage of the Pleistocene. Pleistocene and Holocene carbonates and evaporites are widely distributed along the Kuwait coast.