Caribbean Program

Evolution of the Pacific-origin Caribbean Evolutionary model

In 1966, J. Tuzo Wilson (1966) proposed the idea that the Caribbean lithosphere originated in the Pacific and migrated to its present position in a manner similar to ice-rafting in an Alpine valley. For the next 16 years or so, through the early 80s, both Pacific-origin as well as in-situ (inter-American spreading) models for Caribbean evolution were contemplated by the academic community, fuelled by vast volumes of information gleaned from the latter stages of the Hess Program at Princeton University, DSDP (Leg 15) work in the marine basins, continuous development of Caribbean biostratigraphy and stratigraphy, and a wide variety of other studies from the world community. However, the lack of a quantitative Mesozoic plate kinematic framework during this period caused many workers to reserve judgement on the origin of the Plate, despite the fact that the evolving understanding of Caribbean geology was clearly pointing to a Pacific origin.

In the latest 70s, Caribbean geology indirectly received a huge boost via global plate kinematic studies, first from the development of the Seasat and Geosat databases which allowed workers to trace Atlantic fracture zones in detail for the first time (Haxby et al. 1983), and second from the concurrent realisation (Pindell and Dewey 1982) that the Mesozoic Equatorial Atlantic continental reconstruction was much tighter than that proposed by Bullard et al. (1965). With the resulting definition of an accurate North America-South America relative motion history (Pindell and Dewey 1982; Pindell et al. 1988), it became clear that only minor aspects of Caribbean geology could be explained by intra-American relative plate motions. Caribbean geology, with all its long-lived arcs, suture zones, HP/LT belts, non-Atlantic seismic velocity structure, hot-spot volcanism, lack of tuffs in the Bahamas, Yucatan and northern South American marginal sections, extreme pull-apart basins (Cayman Trough), and metamorphic disparities along linear fault zones (Burke et al. 1984), surely could only be understood in terms of a Pacific origin which required significant relative plate migrations. Although a Pacific origin seemed fairly complex at the time, enough was understood about mantle reference frames by 1982 that a Pacific origin could be viewed as being simpler than an in-situ origin: Pindell and Dewey (1982) noted that the Caribbean was nearly steadfast in the mantle reference frame, whereas the American plates had progressively migrated westward over the mantle and engulfed the former between them as an allochthonous mega-terrane. In addition, the kinematic framework of Pindell and Dewey (1982) required that the Yucatan Block rotated anti-clockwise out of the northern Gulf of Mexico, thus predicting a kinematic model for the Gulf of Mexico that would not be verified from direct basement observation for another 20 years.

By the mid- to late 80s, the template for Gulf and Caribbean evolution was in place (Pindell 1985; Pindell et al. 1988; 1990; Burke 1988; Pindell 1993), and the interpretation of numerous sub-regions across the Caribbean could now be contemplated in terms of causes and effects of kinematic evolution. One of the more important developments during all of this was the realisation of the role of lithospheric flexure in sedimentary forelands: the west-to-east younging of load-induced subsidence within the Caribbean foreland basins on Yucatan, the Bahamas and northern South America as the Caribbean Plate was engulfed by the Americas (Pindell et al. 1988) provided tangible proof for the Pacific origin and migration of the Caribbean Plate. This breakthrough also led to the realisation that northern South America had remained a passive margin throughout the Cretaceous, which at the time had enormous implications for better understanding the hydrocarbon potential of Colombia, Venezuela and Trinidad (Pindell 1991).

During the 90s, much Caribbean research was focussed on documenting the relationship between Caribbean plate tectonics and basin development. Pindell (1993), Pindell and Tabbutt (1995), and the various papers in Pindell and Drake (1998) represent some contributions to this end. Concurrently, the Caribbean became the site for some high-profile debates, some of which continue today and include: the role of the Galapagos Hotspot in Caribbean evolution; how a Late Cretaceous slab gap beneath the Caribbean Plate might have affected the distribution of plume basalts; the number and initial cause(s) of magmatic arcs in the Caribbean; the timing of polarity reversal in the Great Caribbean Arc (Aptian vs Campanian) which first allowed the Caribbean Plate to begin entering the gap between the Americas; the fate of subducted slabs in and around the Caribbean; continental accretion mechanisms during arc-continent collisions; the timing of arc inception along the Costa Rica-Panama Arc; the number of arcs comprising the Guerrero Super-terrane of western Mexico, and if these arc(s) are related to the Greater Antilles Arc; and the details of the migration of Chortis along southern Mexico.

The evolutionary model presented here (click to see the full-sized movie) derives from Pindell and Kennan (2009, in press) and represents my current position on the above and other issues facing Caribbean research today, all built into a refined quantitative plate kinematic framework for the circum-Atlantic region and plotted into the Indo-Atlantic hot spot reference frame of Müller et al. (1993). Choosing a hotspot reference frame affords a visually simple way in which to view Caribbean evolution as a movie; in the one given here, the Caribbean Plate is seen to drift north, veer west, and then come to rest while the Americas continue to drift west and engulf the Caribbean. However, it should be noted that the Müller et al. (1993) frame is not the only popular hotspot reference frame; that of Torsvik (2008) considerably reduces the magnitude of the Cretaceous northward drift of the Caribbean, and this difference will remain an important area for future study. Currently, as least some Caribbean paleomagnetic work is best satisfied by incorporating the northward drift of the Müller reference frame.

The accompanying "movie" (click to see the full-sized movie) is thus an updated synthesis of the widely accepted "single-arc Pacific-origin" model for Caribbean evolution. 10 paleotectonic maps through time integrate new concepts and alterations to the earlier models noted above.

New or revised features of this model, generally driven by new data sets, include:

<a href="Carib_HSRF_animation_small.swf">[View Flash File]</a>
  • The model starts with a refined reconstruction of western Pangaea (see Gulf of Mexico Atlas page)
  • Refined rotational motions of the Yucatán Block during the evolution of the Gulf of Mexico; 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);
  • 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;
  • Campanian initiation of subduction at the Panama-Costa Rica Arc, although a sinistral transform boundary probably pre-dated subduction initiation here;
  • Inception of a north-vergent crustal "Proto-Caribbean inversion zone" along northern South America to account for Cenozoic convergence between the Americas ahead of the Caribbean Plate;
  • 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;
  • 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; and
  • 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.

References cited