Environmental Engineering Reference
In-Depth Information
Figure 3.2
Moraines on the northern slopes of Aksoual (3912 m asl), High Atlas, Morocco.
Cosmogenic nuclide exposure ages (
10
Be) indicate that some of the youngest moraines (marked as
3 on the map) are Younger Dryas in age (12.9-11.7 ka). Reproduced from Hughes
et al.
(2011b),
with permission
10
Be exposure ages much older than the LGM
and oldest moraines have yielded
(Hughes
et al.
, 2011b).
3.2.2 Iberia
The former glaciers of Iberia are particularly important for understanding Pleis-
tocene cold-stage climates. This is because of their proximity to the North Atlantic
and the fact that the Polar Front, important in the development of depression
weather systems, migrated south as far as western Iberia (Ruddiman and McIntyre,
1981) during cold periods. This has important implications for moisture supply
to the Mediterranean region during Pleistocene cold-climate events, which have
long been the subject of intense debate and speculation (e.g. Butzer, 1957;
Tzedakis, 2007).
One of the largest Pleistocene ice caps in Iberia formed over the Sierra Segun-
dera and Sierra de la Cabrera in the Sanabria National Park (Cowton
et al.
, 2009).
There is evidence for at least three phases of glaciation in this area. The most
