Page 167 - Life & Land Use on the Bahrain Islands (Curtis E Larsen)

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and 6000 B.P., when lakes again occupied swales between dunes. An intermediate
period marked by the growth of shallow lakes occurred between 11,500 and 15,000
B.P., indicating renewed increases in rainfall.
The Late Pleistocene lakes were more extensive than those of the Early
Holocene, which were definitely shallow and of relatively short duration.
Ostracods were present in these lakes as were the gastropods Melanoides
tuberculata, Planorbis, Lymnea, Unio, and Corbicula, but fish remains were absent.
The mammalian fauna associated with these late Pleistocene lakes is represented
by Bos primigenius, Bubalus, and Hippopotamus, indicating a contemporary
savannah set in an arid to semi-arid environment.
Playas formed again during the Early Holocene, but were often associated
with flint tool assemblages which McClure relates to the "Neolithic.” Evidence of
human occupations with these lakes is significant for the interpretation of east
Arabian archeology. This wet phase relates well to the Neolithic occupations of
both the Levant and Mesopotamia and the preceramic hunting groups and later
TJbaid groups of eastern Arabia. McClure (1978) notes that Holocene lakes were
also present along wadi floors between 9000 and 6500 B.P., thus wadi flow was not
significant at that time. Major aggradation of streambeds had already occurred.
McClure suggests that in the case of Wadi ad-Dawasir, at least, through flow had
ceased by the Late Pleistocene. The major wadi channels were likely cut during the
Pliocene rather than during the Late Pleistocene, when the lakes of the Rub
al-Khali were formed.
it
Other new paleoenvironmental data have been furnished by Hotzl et al.
(1978:264-95), who reported additional Quaternary lacustrine sediments from two
locations, the Wadi al-Luhy ca. 20 km south of Riyadh and the area of the Hofuf
Oasis. The sedimentary sequence of the former wadi, for example, shows a thick
sequence of still water sediments with abundant gastropod shells identified as
Biomphalaria pfeifferi ruppellii, Bulinus truncatus, Lymnea natalensis, and
Melanoides tuberculata. A date of 8400 + 140 B.P. was determined from a sample
of this fauna and correlates well with McClure’s dated lakes. These gastropods
belong to an Afro-Ethiopian fauna common at the same latitude across Africa.