Careón ophiolite, NW Spain: Suprasubduction zone setting for the youngest Rheic Ocean fl oor

Abstract

The Careón ophiolite (Galicia, NW Iberian Massif) shows lithological and geochemical
features suggestive of an origin in a suprasubduction zone setting. As with other Devonian
ophiolites in the European Variscan belt, it was generated within a contracting Rheic Ocean.
This setting and the general absence of large Silurian-Devonian volcanic arcs on both of the
Rheic Ocean margins strongly suggest that this ocean was closed by intraoceanic subduction
directed to the north. This subduction removed the older normal (N) mid-oceanic-ridge basalt
(MORB) oceanic lithosphere and gave rise to a limited volume of new suprasubduction zone
oceanic lithosphere. The Careón ophiolite is a key element in understanding the evolution of
the Rheic Ocean, which was the main oceanic domain that closed during the Paleozoic convergence
of Gondwana and Laurussia, preceding the assembly of Pangea