The Moni Mélange, Cyprus: an olistostrome formed at a destructive plate margin

Abstract

Detailed mapping has shown that the Moni Mélange of southern Cyprus consists of two separate allochthonous components: a variety of Triassic to Cretaceous sedimentary and volcanic rocks representative of an original continental margin sequence, and substantial sheets of serpentinite derived from Upper Cretaceous Troodos-type oceanic crust. All these allochthonous rocks were emplaced by sliding into an in situ host matrix of Upper Cretaceous bentonitic clays and radiolarian siltstones of deep water hemipelagic facies. The postulated geotectonic setting involves a phase of late Cretaceous northward subduction of Troodos-type oceanic crust beneath a continental margin now located in southern Turkey. Subduction culminated in the Maastrichtian in a major collision of oceanic crust with the adjacent continental margin. This triggered off major oceanward gravity sliding of continental margin rocks. The collision was also associated with deep tectonic slicing of Troodos oceanic crust with the result that sheets of partly serpentinized ultramafic rocks were emplaced by sliding into the host sediments of the mélange from the opposite direction to the other olistoliths. Soon afterwards there was a brief period of submarine erosion, then local tectonic movements ceased, suggesting an end to subduction in the area.