The late Miocene climate of northeastern Africa: unravelling the signals in the sedimentary succession

Abstract

Examination of the depositional profile of the Miocene/Plio-Pleistocene succession at two locations in the Gulf of Suez and seven locations in the Red Sea leads to the conclusion that the Messinian (Zeit Formation and equivalent) sedimentary rocks were deposited at a rate greater than other units of the Miocene/Plio-Pleistocene in these areas. The Zeit Formation contains a significantly higher clastic content than the underlying South Gharib Formation. These two aspects of the stratigraphy are taken to indicate that the Messinian was a time of high rainfall and high sediment yield rates. This period, named the Zeit Wet Phase, stands in marked contrast to the arid conditions of the preceding Tortonian Stage. The latter stage is represented in the Gulf of Suez and Red Sea area by the halite-bearing South Gharib Formation and its equivalents. Physical evidence for a humid Messinian is provided by five lines of evidence involving four sites around the Red Sea and two sites offshore. It is suggested that the Zeit Wet Phase was marked by high monsoonal activity as demonstrated by drilling sites of the Ocean Drilling Program. It is probable that the wet phase peaked in the late Messinian at the time of the low-stand of the Mediterranean during the Messinian Salinity Crisis.