Subsurface structure, stratigraphy, and regional tectonic controls of the Guajira margin of northern Colombia

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2008-05
Authors
Vence, Eleine Melisa
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Abstract

I combine previous data from Mesozoic outcrops in the Guajira Peninsula of northern Colombia with new regional gravity, bathymetric, and seismic interpretations to demonstrate the existence of a 280-km-long, western extension of the Great Arc of the Caribbean (GAC) along the continental margin of Colombia. Seismic data reveal a 80 to 100 km-wide domal-shape basement high lacking seismic reflectivity and mappable for 1800 km from the Aves Ridge to the study area in offshore Colombia. The western extension of the GAC in Colombia and western Venezuela is buried by 700 to 3000 m of continental margin sediments because it collided earlier (Cretaceous-early Paleogene collision) than its subaerially exposed eastern part on the Leeward Antilles Ridge (late Paleogene-Neogene collision). Compilation of radiometric age dates and geologic information from the entire GAC shows that arc magmatism ocurred from 128 to 74 Ma with a general pattern of younging from west to east. I mapped six Upper Eocene to Recent marine seismic sequences that overlie the domal basement high of the GAC using 2400 km of seismic reflection data and 12 wells. Three deformation events affecting the sequences include: 1) late Eocene rifting, in an east-west direction produced half-grabens in the northern part of the area; 2) Oligocene transtension, in the southern part of the area expressed by right-lateral Oligocene strike-slip faulting and extensional basin formation; 2) early - middle Miocene transtension; and 3) late Miocene - early Pliocene Andean uplift and clastic infilling of offshore basins

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