Desert lakes - Climatic Change in Deserts - page 203

rose again to − 280 m before falling rapidly to − 330 m at 39 ka ( = H4). The lake

rose again to − 280 m until 30 ka, when it rose again slightly ( = H3). After a slight

drop, Lake Lisan rose to its maximum level of − 170 m at 25 ka, then fell to − 210 m

= −

at 24 ka ( H2) before rising slightly to 200 m at 22 ka. The lake level then fell

− = −

sharply in two stages to 350 m at 16 ka ( H1), rose briefly to 280 m at 14 ka and

then dropped abruptly to 380 m, at which time we see a transition from a brackish

Late Pleistocene Lake Lisan to the modern hyper-saline Dead Sea (Bookman et al.,
2006 , fig. 4 ). Three conclusions may be drawn from the history of Lake Lisan. First,
the long interval of relatively constant lake level between about 68 ka and 28 ka
indicates strong control over lake level by a sill at this elevation. Second, contrary
to expectation, there is no clear correlation between the Heinrich events in the North
Atlantic (see Chapter 6 ) and lake levels, with H1, H4 and H5 coinciding with low
levels and H2 and H3 coinciding with high levels. Third, peak levels occur just before
the LGM and remained very high throughout the LGM, indicating a pronounced
winter rainfall regime at that time. In Turkey, the late Pleistocene Lake Konya was
also at its maximum level around 23-17 ka (Roberts et al., 1979 ). Later work gives a
more precise age of 25-20.5 ka for this high lake event (Kuzucuoglu et al., 1999 ).
Lake Zihor in the southern Negev Desert of Israel is one of the few lakes in this
region that date back to the Early Pleistocene. The lake sediments are up to 15 m thick
and occupy a tectonic depression that post-dates the Pliocene Arava Formation (Ginat
et al., 2003 ). The central lake facies consists of three beds of white limestone, each
about a metre thick, separated by beds of green detrital limestone up to 7 m thick.
Between the green and white limestone beds are thin layers of black clay 10-20 cm
thick. The white limestone beds contain aquatic mollusca, ostracods and fish-bones
consistent with permanent fresh water in a lake estimated to have been 3-5 m deep.
The lake dried out on three occasions, and red calcic soils developed on fluvial
sediments that interdigitate with the lake deposits. Early Acheulian hand-axes (see
Chapter 17 ) are concentrated around the former lake margins and are typologically
similar to those found in the Ubeidiya Formation in the Jordan Valley dated to around
1.4 Ma, as well as to those found at Olduvai Gorge in Tanzania. Early Pleistocene
Lake Zihor may therefore have served as a reliable source of fresh water for Homo
erectus bands moving out of Africa across the Levant and into Asia and would also
have attracted small and large mammals. Once the lake dried out permanently, the
rivers attracted bands of later Homo erectus , as shown by the presence of Evolved
Acheulian bifacially worked stone tools on and within the alluvial terraces in this area
(Ginat et al., 2003 ).

−

11.8 Desert lakes of Asia with special reference to China
We discuss the Holocene lakes of the Thar Desert in north-west India in Chapter
12 , so our focus here will be on the desert lakes of north-west China, the Tibetan