The trace element geochemistry of Corsican ophiolites

Ultramafic rocks, gabbros, plagiogranites, dolerites and basaltic dikes and pillows lavas of the ophiolite slices of eastern Corsica have been metamorphosed in both oceanic and orogenic environments. The trace element content of the metabasaltic rocks which exhibit a tholeiitic differentiation trend towards a ferrobasaltic composition, is similar to that of oceanic basalts. The cumulate sequence is interpreted to have been formed by fractional crystallization from an olivine-tholeiite magma. The troctolites representing cumulates derived from melts representing liquid fractions in the range F=1-0.85, gabbros from melts with F=0.85-0.45, and ferrogabbros and plagiogranites from melts with F<0.45. An oceanic environment with moderate spreading rates and magmatic processes similar to present-day normal oceanic ridge segments is considered the more probable original setting of the Corsican ophiolites.Financial support by C.N.R. (Italy) and A.T.P. Géodynamique de la Méditerranée Occidentale C.N.R.S. (France)