GEOLOGY AND PETROLOGY OF THE KIZILDAĞ OPHIOLITE (HATAY)

Abstract

In the south of Amanos mountains, a continuous ophiolite succession, the Kızıldağ ophiolite, is exposed from tectonite peridotites, through layered and isotropic gabbros to the sheeted dike complex and pillowed volcanics. The tectonites are composed mostly of harzburgites with minor dunite. The plutonic section comprises a layered gabbroic sequence of mainly wehrlite-gabbro alternations (cpx-ol and ol-cpx-pl cumulates) with minor dunite and Iherzolite, planar laminated nonlayered gabbro (chiefly ol-cpx-pl cumulates) section, an isotropic gabbro section of massive noncumulus hb-px-gabbros with plagiogranite bodies. Therefore, the plutonic sequence with minor ultramafic cumulates differs from that of the other Tauric ophiolites. The sequence also shows drastic lateral thickness and lithological differences. The sheeted dike complex is well developed and its internal structure indicates that additional spreading axes were active during the spreading process. The volcanics are composed of pillowed and massive basaltic lava flows. Cumulates show a limited cryptic variation without any considerable cryptic evolution indicating repeated primitive liquid replenishment of the magma chamber. Chemically the tholeiites of the dike and volcanic complexes are transitional between island arc and mid-ocean ridge basalts and are highly depleted in incompatible elements. Thus the Kızıldağ ophiolite is proposed to represent a kind of oceanic lithosphere produced in a slow spreading center with multiple small magma chambers developed over an already depleted mantle.