A Cretaceous Subduction Zone in Northern Colombia (southern Caribbean plate)?

A metapelite-matrix melange in the northernmost portion of Colombia (southern Caribbean Plate) suggests the presence of an active subduccion zone during the Cretaceous in this area. The mélange is located north of a paleosuture and contains diverse lithologies; the matrix is mainly chlorite schist, muscovite schist, and quartzite and the exotic blocks are of serpentinite and microgabbro. Boulders of eclogite and blueschist found in a Tertiary conglomerate above the melange are interpreted as originated in the melange. The diversity of rock types and degrees of metamorphism could have been originated by mixing of blocks in a descending-plate driven flow as proposed by other workers in similar melanges. It is uncertain whether this subduction zone is related to the migration towards the southeast of the Antilles volcanic arc and its collision with northern South America since the Late Cretaceous and/or to the Andean orogeny. In the last case, the mélange could have been originated west of its current position and emplaced during eastward migration of the proto Caribbean.