Pre-Khuff subsurface stratigraphy in Kuwait

Abstract

Abstract Only a few wells were drilled through the Pre-Khuff section in Kuwait and therefore limited data is available. A composite pre-Khuff stratigraphic section is attempted from this data by utilizing age dating data, the distinctive heavy mineral assemblages and by correlating with regional analogues. In north Kuwait, the oldest sediments encountered are evaporites overlain by carbonates likely belonging to the Hormuz Group of Infra-Cambrian to Early Cambrian age. The Permo-Carboniferous Unayzah Formation unconformably overlies these carbonates. In south Kuwait these strata are missing and the Upper Permian Khuff Formation directly overlies on the older sediments. The oldest sediments in south Kuwait consist of deformed, varve like deposits of finely laminated siltstone and mudstone probably belonging to the Murdama Group of Lower Ediacaran age. The overlying Rubtayn / Mataar Formation of possible latest Precambrian (Ediacaran) to earliest Cambrian age is made up of polymictic conglomerate, red sandstone and mudstone. The Badayi Formation overlies this sequence and consists of volcanics and volcaniclastic tuffs. These are overlain by red sandstone, siltstone and mudstones that could be laterally coeval to the Hormuz Formation. Heavy minerals in the Ediacaran to earliest Cambrian strata are typified by apatite while zircon is dominant in the Unayzah Formation.