干旱区生态环境知识资源中心

After the discovery of new prehistoric and geological sites in eastern Morocco, multidisciplinary studies were made on a regional scale about prehistoric cultures, sediments, grains charcoal, spores and pollen, fauna and chronology. They allowed to treat the following topics : - the evolution of flora and climates during the Rharbian (= Holocene) and Soltanian (= Wurm) periods, i.e. about one hundred thousand years. according to altitude and latitude ; - the palaeoenvironmental meaning of glacis-alluvial terrace systems, calcretes and sheltered deposits.

The palaeoflora are the same as actually and only the vegetation boundaries fluctuate. These variations decrease from North to the South. The Soltanian is a dry period with three humid interstages during which the bioclimate is semi-arid to subhumid The Rharbian is principally humid with three short and periods.

The glacis-terrace systems are built during the arid-humid transition and also during the humid interstadial period like the calcretes at the top of the soltanian formations. The sheltered deposits have recorded both arid and humid stages.