The Pleistocene of the Eastem Mediterranean
19
Alternation of cool and warm conditions in the Eastern basin could be established on grounds of sediment cores and analysis of the fossil planktonic forarniniferan shells (Parker, 1958; Reiss et al., 1971). The dating goes back to the Riss-Würm
or last interglacial and a change from warm to cool and again to warm conditions
could be proved-especially on grounds of the direction of coiling of the foraminiferan Globigerina truncatulinoides. It was easier to synchronize the fluctuations
ofthe planktonic foraminiferan assemblages between Eastern and Western Mediterranean than those of the benthic molluscs. This might be due to the recurrent
near-isolation of the Eastern Mediterranean at the Straits of Sicily: such a semiisolation might have been very significant in hindering the eastward advance of a
benthic assemblage, but of no significance for a planktonic population.
Pfannenstiel (1960) considers that at a presumed Riss glacial sea level of
- 200 m, the Straits of Sicily were only 300 m deep and a few km wide. F ollowing
the results ofthe "Albatross" (in Petersson, 1957) Pfannenstiel reaches the conelusion that at this time "the water exchange between the West and East Mediterranean was practically severed", and that the bottom underwent a stage of
deficient oxygenation because of lack of exchange and the saline stratification of
the Eastern basin. This stratification was due to the increased amount of run off
during the glacial-pluvial period. In the subsequent Würm glacial, the sea level
was at -90 m according to Pfannenstiel-and consequently the isolation of the
Eastern basin must have been less extreme.
With all these data in hand we can now return to the initial assumptions of
Moshkovitz (1968) which opened this chapter.
The course of Pleistocene events in the Eastern Mediterranean was different
from that in the Western Mediterranean. This was a result of late tectonic activity
and the intercalary obstacles for water exchange with the west, and eventually
also ofthe changing runoffregime ofthe major fresh-water supplier, the Nile. The
Eastern Mediterranean and especially the Levant basin were an impoverished
appendix of the Mediterranean during the whole of the Pleistocene, more isolated
from the ocean, with much more environmental instability, fluctuating salinity
and oxygenation but always with high er temperatures than in the West. This is
the reason why the only phase in which the faunal picture is homogenous over all
the Mediterranean is the Tyrrhenian phase. Only then, for the first time since the
late Pliocene, can we speak of an even faunal exchange between the two parts of
the Mediterranean.
But the Tyrrhenian elimax was upset by the Würm glacial. After its first part
(Würm I) there was eventually an improvement and areturn to Tyrrhenian
conditions: the Epi-Monastirian transgression of Zeuner found both in Arabs
Gulf (Halig al Arab west of Alexandria) and the Lebanon at 4 m. But the last two
glacial stadia (Würm 11 and III) followed elose one after another and the "Senegalian" molluscs characteristic of the Tyrrhenian phase disappeared. Peres (1967)
suggests that some species characteristically found in the southern and eastern
parts ofthe Mediterranean, such as the snails Fissurella nubecula, Cypraea lurida,
Purpura haemastoma and Mitrafusca and the decapods Salmoneus jarli, Athanas
amazone, Micropanope rujopunctata, Maja goltziana, and Pachygrapsus transversus are relicts of the tropical West-African influx. These species are absent from the
Western and Northern Mediterranean but known along the West-African sub-
19
Alternation of cool and warm conditions in the Eastern basin could be established on grounds of sediment cores and analysis of the fossil planktonic forarniniferan shells (Parker, 1958; Reiss et al., 1971). The dating goes back to the Riss-Würm
or last interglacial and a change from warm to cool and again to warm conditions
could be proved-especially on grounds of the direction of coiling of the foraminiferan Globigerina truncatulinoides. It was easier to synchronize the fluctuations
ofthe planktonic foraminiferan assemblages between Eastern and Western Mediterranean than those of the benthic molluscs. This might be due to the recurrent
near-isolation of the Eastern Mediterranean at the Straits of Sicily: such a semiisolation might have been very significant in hindering the eastward advance of a
benthic assemblage, but of no significance for a planktonic population.
Pfannenstiel (1960) considers that at a presumed Riss glacial sea level of
- 200 m, the Straits of Sicily were only 300 m deep and a few km wide. F ollowing
the results ofthe "Albatross" (in Petersson, 1957) Pfannenstiel reaches the conelusion that at this time "the water exchange between the West and East Mediterranean was practically severed", and that the bottom underwent a stage of
deficient oxygenation because of lack of exchange and the saline stratification of
the Eastern basin. This stratification was due to the increased amount of run off
during the glacial-pluvial period. In the subsequent Würm glacial, the sea level
was at -90 m according to Pfannenstiel-and consequently the isolation of the
Eastern basin must have been less extreme.
With all these data in hand we can now return to the initial assumptions of
Moshkovitz (1968) which opened this chapter.
The course of Pleistocene events in the Eastern Mediterranean was different
from that in the Western Mediterranean. This was a result of late tectonic activity
and the intercalary obstacles for water exchange with the west, and eventually
also ofthe changing runoffregime ofthe major fresh-water supplier, the Nile. The
Eastern Mediterranean and especially the Levant basin were an impoverished
appendix of the Mediterranean during the whole of the Pleistocene, more isolated
from the ocean, with much more environmental instability, fluctuating salinity
and oxygenation but always with high er temperatures than in the West. This is
the reason why the only phase in which the faunal picture is homogenous over all
the Mediterranean is the Tyrrhenian phase. Only then, for the first time since the
late Pliocene, can we speak of an even faunal exchange between the two parts of
the Mediterranean.
But the Tyrrhenian elimax was upset by the Würm glacial. After its first part
(Würm I) there was eventually an improvement and areturn to Tyrrhenian
conditions: the Epi-Monastirian transgression of Zeuner found both in Arabs
Gulf (Halig al Arab west of Alexandria) and the Lebanon at 4 m. But the last two
glacial stadia (Würm 11 and III) followed elose one after another and the "Senegalian" molluscs characteristic of the Tyrrhenian phase disappeared. Peres (1967)
suggests that some species characteristically found in the southern and eastern
parts ofthe Mediterranean, such as the snails Fissurella nubecula, Cypraea lurida,
Purpura haemastoma and Mitrafusca and the decapods Salmoneus jarli, Athanas
amazone, Micropanope rujopunctata, Maja goltziana, and Pachygrapsus transversus are relicts of the tropical West-African influx. These species are absent from the
Western and Northern Mediterranean but known along the West-African sub-