The Pleistocene of the Eastern Mediterranean
15
assumed Pliocene connections between the Mediterranean and the Northern Red
Sea are based on misdated Miocene fossils.
With the development of new coring techniques, evaporitic layers similar to
those of the Mediterranean were discovered also in the Red Sea. In the Gulf of
Suez (EI Morgan) this layer is 728 m thick, in the southern Red Sea it reaches
nearly 4000 m (after Stoffers and Ross, 1974). The recent DSDP cores established
that the Red Sea evaporitic layers are contemporaneous with those of the Mediterranean and are therefore Messinian (Fig.3). According to Stoffers and Kühn
(1974), the Mediterranean and Red Sea had a common history and formed a
continuous hydrographic system which went through periods of desiccation
caused by the isolation from the Atlantic. Coleman (1974) also states that the
Miocene marine invasion came from the Mediterranean. This situation of "sabkha"-like environments in the Red Sea was interrupted in the Late Miocene or
very Early Pliocene when the Red Sea opened to the Indian Ocean and normal
marine sediments were reported (Stoffers and Ross, 1974). The Pliocene opening
of the proto-Bab el Mandab marked the start of the sea-floor spreading which
formed the present rift of the Rea Sea. One could assume that the start of this
considerable tectonic activity somehow closed the contact to the Mediterranean.
Whitmarsh (1974), based on DSDP material, considers that any post-Miocene
connections with the Mediterranean were short-lived.
A last point needs to be discussed therefore, and this is the early history of the
Isthmus of Suez, which probably appeared in the Upper Miocene. According to
Picard (1943) and Swartz and Arden (1960), this was due to a tectonic upheaval.
Moshkovitz (1968) makes a very important point when he calls attention to the
fact that the Nile sediments, contributed very much to the closure of the Isthmus.
Following the Upper Miocene upheaval of the Ethiopian Highlands, the Nileuntil then a relatively small river-started to carry huge quantities of silt suspensions which coincided with the interruption of the contact between the Paleomediterranean and the Gulf of Suez branch.
From this one may conclude that both the Mediterranean and the Red Selas
underwent hypersaline to brackish periods during the Upper Miocene, which
most probably exterminated preexistent fauna. The Paleomediterranean was repopulated in the Pliocene with tropical West African elements, whereas the Red
Sea received the ftrst influx of Indo-Paciftc fauna.
The "totally dissimilar" [Ekman's (1967) quotation marks] fauna of the two
seas before the opening of the Suez Canal in 1869, has its origins in a completely
separate evolution from the Miocene onwards. The question as to why the high
eustatic Pleistocene sea levels did not result in a "pre-Lessepsian" intermingling of
the two faunas will be discussed in the next chapter.
1.2 The Pleistocene of the Eastern Mediterranean
Since at least the start of the Pleistocene [1.8 million years ago, Reiss (1968)],
the Mediterranean ceased to be an environmental and faunistic whole. In the
words ofMoshkovitz (1968) the Eastern Mediterranean and especially the Levant
basin were a periphery of the Western Mediterranean.
15
assumed Pliocene connections between the Mediterranean and the Northern Red
Sea are based on misdated Miocene fossils.
With the development of new coring techniques, evaporitic layers similar to
those of the Mediterranean were discovered also in the Red Sea. In the Gulf of
Suez (EI Morgan) this layer is 728 m thick, in the southern Red Sea it reaches
nearly 4000 m (after Stoffers and Ross, 1974). The recent DSDP cores established
that the Red Sea evaporitic layers are contemporaneous with those of the Mediterranean and are therefore Messinian (Fig.3). According to Stoffers and Kühn
(1974), the Mediterranean and Red Sea had a common history and formed a
continuous hydrographic system which went through periods of desiccation
caused by the isolation from the Atlantic. Coleman (1974) also states that the
Miocene marine invasion came from the Mediterranean. This situation of "sabkha"-like environments in the Red Sea was interrupted in the Late Miocene or
very Early Pliocene when the Red Sea opened to the Indian Ocean and normal
marine sediments were reported (Stoffers and Ross, 1974). The Pliocene opening
of the proto-Bab el Mandab marked the start of the sea-floor spreading which
formed the present rift of the Rea Sea. One could assume that the start of this
considerable tectonic activity somehow closed the contact to the Mediterranean.
Whitmarsh (1974), based on DSDP material, considers that any post-Miocene
connections with the Mediterranean were short-lived.
A last point needs to be discussed therefore, and this is the early history of the
Isthmus of Suez, which probably appeared in the Upper Miocene. According to
Picard (1943) and Swartz and Arden (1960), this was due to a tectonic upheaval.
Moshkovitz (1968) makes a very important point when he calls attention to the
fact that the Nile sediments, contributed very much to the closure of the Isthmus.
Following the Upper Miocene upheaval of the Ethiopian Highlands, the Nileuntil then a relatively small river-started to carry huge quantities of silt suspensions which coincided with the interruption of the contact between the Paleomediterranean and the Gulf of Suez branch.
From this one may conclude that both the Mediterranean and the Red Selas
underwent hypersaline to brackish periods during the Upper Miocene, which
most probably exterminated preexistent fauna. The Paleomediterranean was repopulated in the Pliocene with tropical West African elements, whereas the Red
Sea received the ftrst influx of Indo-Paciftc fauna.
The "totally dissimilar" [Ekman's (1967) quotation marks] fauna of the two
seas before the opening of the Suez Canal in 1869, has its origins in a completely
separate evolution from the Miocene onwards. The question as to why the high
eustatic Pleistocene sea levels did not result in a "pre-Lessepsian" intermingling of
the two faunas will be discussed in the next chapter.
1.2 The Pleistocene of the Eastern Mediterranean
Since at least the start of the Pleistocene [1.8 million years ago, Reiss (1968)],
the Mediterranean ceased to be an environmental and faunistic whole. In the
words ofMoshkovitz (1968) the Eastern Mediterranean and especially the Levant
basin were a periphery of the Western Mediterranean.