The role of continental-margin architecture on models of ophiolite emplacement

Abstract

Ophiolite obduction, the process by which part of the oceanic crust overlaps the continental margin, is challenging when it comes to the geodynamic reconstruction of lithospheric processes. This buoyancy difference between dense oceanic crust and the relatively buoyant continental crust makes the obduction of the oceanic crust difficult, if not impossible, when only buoyancy forces are considered. To overcome the difficulties posed by the negative buoyancy, the initial configuration of the oceanic basins must have specific thermal and geometric constraints. Here we present a systematic investigation of the geometrical and the geodynamical parameters which control the ophiolite emplacement process. Our study reveals which parameters are the most important during ophiolite emplacement and which are the most optimal geometries that favour ophiolite emplacement. We focus on “Tethyan” ophiolites which are characterized by relatively small inferred basin size and are commonly found in Mediterranean region. Based on a combination of various parameters, we identified the most susceptible configurations for ophiolite obduction. Our models demonstrate, in agreement to geological data, that the obducted lithosphere must be young and the length of the Ocean-Continent-Transition zone must be relatively sharp in order to achieve ophiolite obduction. Thematic collection: This article is part of the Ophiolites, melanges and blueschists collection available at: https://www.lyellcollection.org/topic/collections/ophiolites-melanges-and-blueschists Supplementary material: https://doi.org/10.6084/m9.figshare.c.6922526