The Red Sea — Gulf of Aden: Biostratigraphy, Lithostratigraphy and Palaeoenvironments

Abstract

Sediments of Palaeozoic, Mesozoic and early Palaeogene ages experienced a similar geological history in Ethiopia, Yemen and Somalia. During the late Eocene, however, uplift and differential erosion took place, prior to rift development in the middle Oligocene, when the proto‐Gulf of Aden became established. To a certain extent, a similar sequence of events had also taken place in those regions of Egypt, Sudan, Ethiopia, Yemen and Saudi Arabia which border the Red Sea, but post‐Eocene subsidence is now believed to have commenced during the late Oligocene in the southern Red Sea and progressed later, during the early Miocene, in the northern Red Sea and Gulf of Suez. Timing of this progressive development of the Gulf of Aden rift complex through the Red Sea and Gulf of Suez is well constrained by biostratigraphy, and provides a new approach to the understanding of lithological variations within the region. These lithological variations have, until now, only been considered on a country‐specific basis, thus hindering establishment of a regional history of sedimentation. The well‐understood and well‐documented lithostratigraphic nomenclature of the Miocene succession of the Gulf of Suez has been used as a reference, or type, with which the lateral facies variations within the Red Sea have been compared. By this method only has it been possible to produce palaeoenvironmental maps for the entire study region, and for each formation and member. Lateral equivalents of the Gulf of Suez Nukhul, Rudeis, Kareem, Belayim, South Gharib. Zeit, Wardan and Shagara Formations have been identified within the Red Sea syn‐rift and post‐rift episodes.

The Red Sea and Gulf of Aden Basins

“…Offshore from the Hadhramaut region, maxima of about 2000 m and 1100 m of the syn-rift Shihr Group and post-rift Sarar Formation, respectively, were encountered in six exploratory wells (Haitham and Nani, 1990;Bott et al, 1992;Hughes and Beydoun, 1992). Thinner sections of the same age were seen in the two wells drilled offshore central Somalia (Fig.…”

“…Cretaceous volcanic units have been encountered below the Mukawar Formation in offshore wells ( Fig. 9; Hughes and Beydoun, 1992).…”

Sedimentary basins of Yemen: their tectonic development and lithostratigraphic cover

“…The Gulf of Aden rift system propagated from the Alula/Ra's Fartaq trend in the east to the Bab Al-Mandab in the west, and thus joined the Owen fracture zone to the Afar hotspot (Courtillot 1980;Fournier et al 2010;Leroy et al 2004;Manighetti et al 1998). The Red Sea rifting propagated from south to north, joining the Dead Sea and Levant strike-slip fault (Bott et al 1992;Hughes et al 1991;Hughes and Beydoun 1992). The Red Sea was cut off from India Ocean via Bab Al-Mandab in the late Middle Miocene, giving rise to thick evaporite deposition in the Red Sea during this time.…”

Early magmatism in the greater Red Sea rift: timing and significance

“…There have been long running debates about the ages of these units and where precisely to place the base-rift unconformity. Micropaleontological studies of exploratory wells and some outcrops have suggested that the oldest syn-rift formations, exclusive of the very southern Red Sea, are ϳ23 Ma, near the Oligocene-Miocene boundary (Bunter and Abdel Magid 1989;Hughes and Beydoun 1992;McClay et al 1998;Bosworth et al 1998;Hughes et al 1999). Other interpretations have placed the base syn-rift unconformity within the Late Oligocene (Dullo et al 1983;Bayer et al 1988;Purser and Hötzl 1988;El Barkooky and El-Araby 1999;Bosworth and McClay 2001;Jackson et al 2006;Jackson 2008), or even Early Oligocene (Hughes and Filatoff 1995;Koeshidayatullah et al 2016).…”