THE NATURE OF PLEISTOCENE VOLCANISM IN NORTHEASTERN JORDAN

The distribution of major and minor elements in alkali basalt from Northestern Jordan indicates homogeneous lava from a mantle source.The Mgo and Mg-values (Mg/Mg+Fe) in samples from the volcanoes exhibit different degrees of fractionation which lead to the formation of these rocks. The low concentration of incompatible trace elements would imply derivation from partial melting of uppermantle spinel-lherzolite zone. The magma includes spinel-lherzolite xenoliths; this would indicate derivation and equilibration under uppermantle condition with low degree of melting (<20%). The spinel-lherzolite did not equilibrate with the melt indicate that transport from mantle to the surface was rapid, olivine in xenolith show no zoning.