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Early-subduction-related orogeny in the northern Andes: Turonian to Eocene magmatic and provenance record in the Santa Marta Massif and Rancheria Basin, northern Colombia

Abstract:

The timing of orogeny in the northern Andes and the mechanism driving it are still debated. We have studied the age, composition and provenance of granitoids and sandstones of the Santa Marta Massif and Rancheria Basin, northern Colombia, to relate deep-seated and surface tectonic processes attending the Late Cretaceous-Palaeogene history of the northern Andes. Our results indicate the development of five tectonic episodes: (1) collision of northwestern South America with a 92-80 Ma Caribbean arc (70 Ma); (2) late-collisional to early-subduction metamorphism and magmatism (65 Ma); (3) distal accumulation of a thick siliciclastic sequence (60-58 Ma); (4) renewed arc magmatism (58-50 Ma); and (5) magmatic quiescence and block uplift (post-50 Ma). The first episodes are related to the onset of subduction, and the last episode is related to shallow subduction and oblique convergence. Similar events in Colombia and Ecuador reveal that the Late Cretaceous-Eocene orogeny of the northern Andes was influenced by the collision and subduction of the Caribbean oceanic plate. © 2010 Blackwell Publishing Ltd.