Paläoböden unter Hangschuttdecken im nordafrikanischen Sahel (Republic Niger)

Abstract

Buried soils from the Niger Sahel, which formed on different substratums as crystalline and sedimentary bedrock, are described. Those soils are preserved in partly steep slope positions and are coated by thick covers of talus. They are found in southern Sahel as well as in northern Sahel and in the Air Mountains. From the pedogenetical point of view the soils formed in a climate which provided a minimum of about 1000 mm of annual precipitation during the rainy period of five months. They presumably formed during the late Quaternary, as even in steep slope positions their profiles are in a good state of preservation. The late Pleistocene humid period between 40 000 and 20 000 y.b.p. is considered to be the last time of development of palaeosols, which in the Niger Sahel caused an intensive soil development on ancient dunes. The talus coverings are not residual ones. They were presumably formed when climate became arid during the intensive drought duration at the close of the Pleistocene. During the Holocene on the talus coverings soils were again formed, which typologically clearly differ from the palaeosols.