Magnetic anisotropy of a sub-ophiolitic metamorphic sole (Mersin ophiolite, Türkiye)

Authors : Buğra ÇAVDAR, Antony MORRİS, Mark ANDERSON, Luca MENEGON, Osman PARLAK

Pages : 1-14

Doi:10.19111/bulletinofmre.1081170

View : 27 | Download : 8

Publication Date : 2023-04-17

Article Type : Research Paper

Abstract :The Mersin ophiolite of southern Turkey is a well-exposed, Late Cretaceous, Neo-Tethyan suprasubduction zone ophiolite. It is underlain by metamorphic sole rocks inferred to have formed at the top of a down-going plate during subduction. These have a well-developed foliation and lineation observable in the field insert ignore into journalissuearticles values(defined by the preferred orientations of hornblende and plagioclase crystals);. Here we present the first magnetic fabric data reported from the Mersin ophiolite with such settings. Anisotropy of low field magnetic susceptibility ellipsoids in sampled amphibolites have clustered, NW-plunging minimum principal axes representing poles to a SE-dipping magnetic foliation that aligns with the macroscopic metamorphic foliation plane seen in the field. Maximum AMS principal axes define a SE-plunging magnetic lineation that is parallel to the macroscopic metamorphic lineation. Oblate magnetic fabrics at specimen-level and an overall triaxial fabric at localitylevel in these rocks are consistent with the development of the dominant metamorphic fabric by a combination of pure shear flattening and simple shearing during the formation and exhumation of the Mersin sole rocks. These observations are compatible with a recent tectonic model for the evolution of the ophiolite based on paleomagnetic data that invokes flattening and exhumation of the down-going slab in an incipient subduction zone during supra-subduction zone spreading.
Keywords : Magnetic Anisotropy, Rock Magnetism, Amphibolites, Ophiolite, Metamorphic Sole