LATE CRETACEOUS TO RECENT PALEOENVIRONMENTS OF THE SAUDI-ARABIAN RED-SEA

Integrated micropalaeontological, palynological and lithological analy sis of the Upper Cretaceous to Recent sedimentary succession, as obser ved in deep and shallow well drill cores and field samples, has reveal ed a highly varied history of environments of deposition. Supratidal, freshwater conditions prevailed during the Late Cretaceous, Oligocene, Early and Late Miocene to Recent. Marginal marine conditions are repr esented in the Palaeocene to Lower Eocene successions, but without any indication of hypersaline sabkha environments. Marginal marine condit ions involving periodic hypersaline sabkha and hypersaline lake develo pment existed during the Early and Late Miocene. In most of the studie d areas, very deep, normal salinity marine conditions, within the uppe r bathyal regime, existed during the Early Miocene; episodes of marine suboxia are indicated by the microfaunal and organic facies character . Later, during the late Early Miocene and early Middle Miocene, simil ar deep marine conditions prevailed, but with episodes of hypersalinit y that culminated in the late Middle Miocene. Such conditions are beli eved to have resulted from the isolation of the basin and the precipit ation of deep marine precipitates. These changes in palaeoenvironment are considered to reflect episodes of eustatic sea level fluctuation, which are possibly linked to the structural evolution of the Red Sea. Copyright (C) 1996 Elsevier Science Ltd