Page 55

between Unit 1 and the Ouljian fossil beach (Supra, 3-
1, Unit 1).
6 - CHRONOLOGY AND DURATION OF
THE MAIN MORPHODYNAMICAL EVENTS
On the basis of these results, we suggest the following
sequence of morphodynamic events in the Oued
Noun valley (fig. 5 and 6):
6.1 - OXYGEN ISOTOPE STAGE 5 (128-75kabp)
The first alluviation phase is a high-energy fluvial
deposit, (Unit 1) for which the U/Th datings remain uncertain.
One hypothesis is that this conglomerate dates to
stage 5, as suggested above. This was a coarse sedimentation
into a deep valley, with the same valley floor
almost as to day. The size of the boulders and gravels
indicates high stream power and large floods, with deposits
of both proximal and distal origin. The classic
interglacial stage 5 is known to have been a period of
valley-floor incision in South Morocco (Weisrock &
Rognon, 1977), as in the whole Mediterranean area
(Macklin et al., 2002). Evidence for a major humid
phase during the last Interglacial in the Sahara has also
been evoked (Petit-Maire et al., 1994).
Alternatively, the whole of Unit 1, and the base of
Unit 2 can be considered as more recent (ca. 55 - 50 ka).