Major oxide geochemistry and origin of the Troodos ophiolitic complex

Abstract

New major element data from the layered and doleritic (static) gabbros, the plagiogranites, the sheeted complex and the volcanic series of the Troodos ophiolite complex clearly show that : the plutonic rocks are indiscutably the products of fractional crystallization and that the volcanics form continuous and smooth trends on oxide variation diagrams. This continuity in trend is also apparent in the case of the sheeted complex and the lower part of the volcanic series (Lower Pillow Lavas) when Miyashiro's diagrams are used. The role of metamorphism and related phenomena such as calcitisation, albitisation, adularisation and silicification is emphasised. It is proved once more that, despite ocean floor metamorphism, the Troodos ophiolite was derived from tholeiitic magma with calc-alkaline affinities. Furthermore both geochemical and field evidence indicate that the plutonic, sheeted complex and volcanic rocks are consanguinal.