THE TROODOS MASSIF OF CYPRUS: ITS ROLE IN THE EVOLUTION OF THE OPHIOLITE CONCEPT

Over the past 40 years, study of the Troodos massif of Cyprus has generated many of the current ideas on the origin and emplacement of ophiolites. Although many interpretations have been controversial, the Troodos complex is now generally believed to have formed at multiple spreading axes in a supra-subduction zone environment resulting from the collision of the African and Eurasian Plates in the Late Cretaceous. The sheeted dyke complex provides unequivocal evidence of spreading along several axes currently marked by structural grabens. The grabens formed by listric normal faulting during crustal extension and mark the loci of hydrothermal vents around which the numerous sulphide orebodies formed. Alteration in the lavas is nonpervasive and fresh volcanic glass occurs sporadically through the extrusive sequence. The lavas are arc tholeiites and boninites, indicating formation in a suprasubduction zone environment although a remnant of MORB mantle is preserved. Intrusive relationships between deformed and undeformed plutonic rocks and between plutonic rocks and sheeted dykes provide unequivocal evidence of multiple magma chambers beneath Troodos at the time of formation. Uplift and emplacement of the massif resulted from subduction of the leading edge of the African plate beneath the ophiolite. The Mamonia complex on the southern flank of Troodos is a melange composed of material accreted from the downgoing slab. Although individual ophiolites around the world are highly variable, many have features in common with the Troodos complex and presumably formed in a similar manner. This talk will highlight the evolution of ideas regarding the Troodos massif and discuss some of the controversies resulting from study of this body.