Comparison of Late Cretaceous-Cenozoic deformation and basin formation along the northwestern Caribbean plate boundary on the Honduran borderlands-Nicaraguan Rise and southeastern Caribbean plate boundary in Colombia
Sanchez, Carlos Javier 1980-
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Most geoscientists working in the Caribbean now agree that the area composing the present-day Caribbean plate formed as a large oceanic plateau in the eastern Pacific Ocean and was transported into its present location along strike-slip faults and subduction zones. This dissertation studies the structure and basin formation on two areas on opposite sides of the Caribbean separated by a distance of ~1400 km: 1) The offshore Honduran borderlands (HB) and western Nicaraguan Rise (NR) at the northwestern margin; and 2) the onshore Cesar-Rancheria Basin (CRB) along the southeastern margin of the Caribbean plate. These areas show deformation events that record the west to east motion of the Caribbean plate and its proposed exotic place of tectonic origin in the eastern Pacific Ocean. Five tectonic phases in the northern area include: 1) Late Cretaceous uplift and south-dipping thrusting related to the collision between the Chortis continental block and the Great Arc of the Caribbean (GAC); 2) Eocene sag basins forming in the NR and minor extension in the HB; 3, 4) two phases of late Miocene and Miocene-Pliocene accelerated extension (transtension) and subsidence mainly in the HB; and 5) Pliocene to recent minor fault activity in HB and the development of a stable carbonate platform on the NR. In comparison, the southeastern Caribbean plate boundary in Colombia is dominated by two intraplate shortening events: 1) an early–middle Eocene, NW-SE shortening and uplift event that produced east-dipping Cretaceous and Paleocene strata beneath a major unconformity; this event is consistent with the collision of the leading edge of the GAC with the northwestern continental margin of the South American plate; and 2) a late Miocene–Pliocene, east-west shortening with major exhumation of the eastern CRB during collision between the Panama arc and northwestern South America. Both study areas show west-to-east, diachronous arc-continental collision of the leading edge of the GAC with continental areas; in the northwestern Caribbean, collision was followed by transtension as the plate moved east, while this same eastward plate motion produced transpression in the southeastern Caribbean.