The EW-trending Caribbean - South American plate boundary consists of several allochthonous belts two of which contain high-pressure / low-temperature (HP/LT) metamorphic rocks (Cordillera de la Costa and Villa de Cura belts) formed in a mid-Cretaceous subduction zone. The Cordillera de la Costa belt is lithologically, petrologically and geochronologically very heterogeneous with three distinct assemblages with oceanic, continental margin and continental basement affinities. The continental basement has Early Paleozoic U/Pb ages. Geothermobarometry of the eclogites and their country rocks indicates they were formed at great depths (2.2 GPa); they were retrograded following an almost isothermal decompression path. In contrast, the Villa de Cura belt consists solely of metavolcanic and metasedimentary rocks of oceanic affinity. The belt consists of four subbelts, each a coherent blueschist sequence that reached a maximum pressure of 0.8 GPa with minimal retrogression following a "Franciscan" decompression path. The southernmost subbelt may record initiation of subduction at 96 Ma. Both HP/LT belts formed as a result of subduction of the proto-Caribbean lithosphere beneath the Leeward Antilles arc when the arc was located approximately where the Panama arc is today. The Cordillera de la Costa belt may have formed where the arc collided in a very oblique fashion with a microcontinental block related to the South American plate whereas the Villa de Cura belt formed in the same arc but in an intraoceanic environment. The initiation of subduction is related to reversal of subduction zone polarity of the "Great Arc of the Caribbean." Exhumation of both belts may have resulted from right-oblique convergence, displacement partitioning, and arc-parallel extension in the subduction zone. In the Villa de Cura belt, the metamorphic packages were stacked upon each other in a subduction zone duplex. The thickness of all belts has decreased because of arc-parallel (out-of-the-plane) stretching. Several areas in these belts have not been studied yet.