Metamorphic gradient modification in the Early Cretaceous Northern Andes subduction zone: A record from thermally overprinted high-pressure rocks

New field observations and petrological data from Early Cretaceous metamorphic rocks in the Central Cordillera of Colombian Andes allowed recognition thermally overprinted high-pressure derived oceanic crust protoliths. The obtained path suggests that evolved blueschist to eclogite facies towards upper amphibolite granulite transitional conditions. Eclogite conditions, better recorded mafic protoliths, are revealed by relic lawsonite phengite, bleb- worm-like diopside-albite symplectites, as well garnet core composition. Upper high pressure overprinting is supported coarse-grained brown-colored Ti-rich amphibole, augite, oligoclase recrystallization, record partial melting leucosomes. Phase equilibria pressure-temperature (P-T) modeling suggest initial conditions M1 yielding 18.2–24.5 kbar 465–580 °C, followed stage M2 6.5–14.2 580–720 °C. Retrograde M3 through chlorite thermometry yield temperatures ranging around 286–400 °C at pressures below 6.5–11 kbar. clockwise P-T path, zonation pattern revealing a decrease Xgrs/Xprp related Mg# increment rim, presence veins, regional constraints, document modification thermal structure active subduction zone Northern during Cretaceous. Such gradient within interface associated with slab roll-back geodynamics where hot mantle inflow was triggered. This scenario also argued reported trench-ward magmatic arc migration multiple extensional basin formation this period. presented example constitutes first report roll-back-related metamorphism Caribbean Andean realms, representing an additional piece evidence for margin-scale event modified northwestern border South America