Problème du rajeunissement des sols issus de l'altération de roches volcaniques par des éruptions récentes de cendres, aux Nouvelles-Hébrides et aux îles Canaries

Abstract

Abstract. - Two soils, one from Aoba (New Hebrides), the other from Tenerife (Canarian Islands), the rejuvenation of which by a fall of volcanic ashes has been dated (by 14 C), show that, in a humid tropical or subtropical environment, the recent rejuvenation leads to pedological forms relatively less maturated than the normal soils type. In Aoba, they are one thousand years old, saturated and slighty evoluted andosols, in Tenerife appear andic brown earths that are less than 9000 years old and bury tropical paleosols. It is noteworthy in Aoba, that only one thousand years has been enough to form halloysite, whereas Aomine and Miyauchi (1963) estimated tah 8000 years have been necessary in the case of the Japanese andosols.

The role of metals in soils and accumulation in the laurel forest of La Gomera (Canary Islands, Spain): preliminary results

“…However, the contents of Fe, Si and Ni were greater in the surface layer and not correlated with those of the deep horizons, indicating a significant exogenous supply of these metals. Such inputs may include new volcanic ash (Quantin et al , 1975), Sahara dust deposition (Viana et al , 2002) and anthropogenic pollution (Tausz et al , 2005).…”