Caribbean-South America oblique collision model revised

Abstract

AbstractThe ‘Caribbean oblique collision model’ invokes a three-stage evolution for Ecuador–Colombia–Venezuela–Trinidad: (1) Jurassic rifting; (2) Oxfordian–Neogene passive margin subsidence beside the spreading (until Campanian) Proto-Caribbean Ocean; (3) Campanian to Miocene oblique collision of the Caribbean Arc from the west, producing a craton-verging thrust belt and foreland basin. The timing of these stages is incorrect. Rifting ended 70 Ma later (Coniacian), with Cuba breaking away from Venezuela–Trinidad. Brief Proto-Caribbean spreading (Santonian–Campanian) was followed by slow (amagmatic) subduction below Venezuela and Trinidad, driven by inter-Americas convergence, so the passive margin lasted just 10–15 Ma in eastern Venezuela, not 140 Ma (sic). Convergence changed from WSW to SSE in Paleocene time, causing Proto-Caribbean subduction under Colombia too. Subduction in Venezuela–Trinidad drove upper crustal nappes cratonward, metamorphosing overridden rift deposits of the Inner Nappe (Cordillera de la Costa) and feeding Campanian–Miocene olistostromes to aProto-Caribbean‘pre-arc’ foreland basin. The Caribbean Arc collided with Ecuador to Guajira from Campanian time and passed ‘Guajira corner’ in Early Oligocene time, not Paleocene, then migrated SE forming the Gulf of Venezuela–Falcón, diachronous (Oligo–Miocene), transform-related extensional basin, followed by oblique collision (obduction) in central Venezuela to Trinidad driving a Mio–PlioceneCaribbeanforeland basin. Caribbean relative motion switched to eastward near 2.5 Ma, not 12 Ma as is widely believed. The new plate boundary follows the Eastern Cordillera–Mérida Andes–San Sebastián–El Pilar–Trinidad Central Range fault system. Pull-apart basins date from 2.5 Ma at the Cariaco and intra-Gulf of Paria stepovers. Elsewhere the boundary is characterized by transpressional uplift, overwhelmed in some areas (e.g. Gulf of Barcelona; greater Gulf of Paria) by subsidence due to dissolution of inferred, buried, Neocomian rift halite since the Middle Miocene (climate change). The revised timings of events, and the revival of the geosyncline-era concept of Late Cretaceous–Palaeogene orogeny in northern South America, will affect petroleum exploration.