Role of extensional tectonics in exhumation of eclogites and blueschists in an oblique subduction setting: Northeastern Venezuela

Eclogites and blueschists in northeastern Venezuela belong to a mid- to Late Cretaceous subduction complex-fore-arc terrane related to right-oblique subduction of the Proto-Caribbean plate beneath the Farallon plate along the Leeward Antilles volcanic island arc. These rocks were metamorphosed at high pressures and subsequently underwent retrogradation at decreasing pressures but at constant or slightly increasing temperatures. They underwent five phases of deformation: three synmetamorphic and two postmetamorphic. The major principal extensions (X axes) of each of the three synmetamorphic deformations are subparallel</em> to the volcanic arc. The extension parallel to the arc and the associated exhumation and uplift of the subduction complex-fore-arc terrane may have resulted primarily from an increase of the arc-parallel displacement rate of this terrane caused by an increase of obliquity of plate convergence.