||Tectonic evolution of the Gulf of Mexico, Caribbean and northern South America in the mantle reference frame: an update
||James Pindell & Lorcan Kennan
||James, K., Lorente, M. A. & Pindell, J. (eds), The geology and evolution of the region between North and South America, Geological Society, London, Special Publication, expected late 2009
We present an updated synthesis of the widely accepted
single-arc Pacific-origin and
Yucatán-rotation models for Caribbean and Gulf of Mexico evolution, respectively. 14 palaeogeographic maps through time integrate new concepts and alterations to earlier models. Pre-Aptian maps are presented in a North American reference frame. Aptian and younger maps are presented in an Indo-Atlantic hot spot reference frame which demonstrates the surprising simplicity of Caribbean-American interaction. We use the Müller et al. (1993) reference frame because the motions of the Americas are smoothest in this reference frame, and because it does not differ significantly, at least since c. 90 Ma, from more recent
moving hot spot reference frames. The Caribbean oceanic lithosphere has moved little relative to the hot spots in the Cenozoic, but moved north at c. 50 km/Ma during the Cretaceous, while the American plates have drifted west much farther and faster and thus are responsible for most Caribbean-American relative motion history. New or revised features of this model, generally driven by new data sets, include: (1) refined reconstruction of western Pangaea; (2) refined rotational motions of the Yucatán Block during the evolution of the Gulf of Mexico; (3) an origin for the Caribbean Arc that invokes Aptian conversion to a southwest-dipping subduction zone of a trans-American plate boundary from Chortís to Ecuador that was part sinistral transform (northern Caribbean) and part pre-existing arc (eastern, southern Caribbean); (4) acknowledgement that the Caribbean basalt plateau may pertain to the palaeo-Galapagos hot spot, the occurrence of which was partly controlled by a Proto-Caribbean slab gap beneath the Caribbean Plate; (5) Campanian initiation of subduction at the Panama-Costa Rica Arc, although a sinistral transform boundary probably pre-dated subduction initiation here; (6) inception of a north-vergent crustal inversion zone along northern South America to account for Cenozoic convergence between the Americas ahead of the Caribbean Plate; (7) a fan-like, asymmetric rift opening model for the Grenada Basin, where the Margarita and Tobago footwall crustal slivers were exhumed from beneath the southeast Aves Ridge hanging wall; (8) an origin for the Early Cretaceous HP/LT metamorphism in the El Tambor units along the Motagua Fault Zone that relates to subduction of Farallon crust along western Mexico (and then translated along the trans-American plate boundary prior to onset of SW-dipping subduction beneath the Caribbean Arc) rather than to collision of Chortis with Southern Mexico; (9) Middle Miocene tectonic escape of Panamanian crustal slivers, followed by Late Miocene and Recent eastward movement of the
Panama Block that is faster than that of the Caribbean Plate, allowed by the inception of E-W trans-Costa Rica shear zones. The updated model integrates new concepts and global plate motion models in an internally consistent way, and can be used to test and guide more local research across the Gulf of Mexico, the Caribbean, and northern South America. Using examples from the regional evolution, the processes of slab break off and flat slab subduction are assessed in relation to plate interactions in the hot spot reference frame.
||Full Text and Figures (early preprint), 4.2 Mb
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