AHSTRMT . Forty-three samples of volcanic rocks were selected from 5 widely spaced mineralized areas within the Hulayfah Group in the Arabian Shield . These samples were analysed for major and minor oxides as well as Nb, Zr, Y, Ti and P . The analyses were plotted on some of the commonly used petrochemical discrimination and variation diagrams in a trial to test the mobility of elements, but not to deduce tectonic selling or magma type . Nh and Y showed the highest mobility. Ti and Zr showed

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... atively moderate mobility with Ti being somewhat more mobile. but P showed the least mobility . It is suggested that the partial pressure of carbon dioxide . and whether it is buffered by an external source or not. have a considerable effect on the mobility of these clements during metamorphism and alteration .