Petrology and Origin of Ultramfic Xenoliths from North Eastern Jordan Volcanoes
The distribution of major, minor and trace elements in the Cenozoic alkali basalt from north-eastern Jordan indicates a homogeneous lava flow from a mantle source. These basaltic rocks contain abundant upper mantle xenoliths (spinal lherzolite, harzburgile and olivine- websterite). Theses xenoliths contain olivine, orthopyroxne, clinoporoxene and a few amounts of spinal. Their mineral assemblages, chemistry, texture and major elements abundances indicate they were derived and equilibrated under upper mantle conditions within temperature range for 970-1090°C. Pressure estimates based on the spinal lherzolite stability field restrict the xenoliths source depth to around 65 km. The concentrations of incompatible trace elements (Ba, Rb and Sr.) imply a derivation from ultramafic predictive source from the upper mantle with low degree of melting (<20%). Low concentration of Lithium and Rubidium in the basalt is used as an argument against the contamination of the basaltic magma during its journey to the surface.
Copyright: © 2007 Hassan Al-Fugha and Mazen AL-Amaireh. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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- Alkali olivine basalt
- contamination of the basaltic magma
- ultramfic xenoliths