Caribbean
The rocks documenting subduction zones in the Caribbean realm formed during the Lower Cretaceous, Upper Cretaceous and Tertiary. The information retrieved from these rocks is essential in building valuable plate-tectonic models for the region, as they document the position and thermal regimes of subduction zones fringing the plate. But, before the basic geology and metamorphic petrology of subduction complexes of the region is evaluated, it is worth considering the plate tectonic models currently proposed.
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The Caribbean plate occupies a position in between two mayor plates, the North and South American plates. These two plates are dominated by continental masses. This fact has controlled part of the lengthy evolution of the Caribbean plate. |
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The plate is bounded by two active subduction zones which have two associated active trenches and volcanic arcs, the Lesser Antilles (to the East) and the Central American (to the West) trenches/arcs, and by two complex transform-trascurrent fault zones, the Motagua-Polochic-Swan-Bartlett/Oriente to the North, and the northern South American fault system to the South, where subduction of the Caribbean plate below South America is active at present. The above mentioned configuration developed during the Late Eocene/Early Oligocene. Since then, the Yucatan basin (developed during the latest Cretaceous- Middle Eocene) and the Cuban segment of the peri-Caribbean orogenic belt are attached to the North American plate. |
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The peri-Caribbean orogenic belt runs from Guatemala through the Greater and Lesser Antilles to northern South America. The belt contains the active volcanic arc of the Lesser Antilles, where the Atlantic subducts below the Caribbean Plate, but it also contains volcanic arc rocks of Cretaceous to Tertiary age that documents a lengthy history of subduction associated with the leading edge of the Caribbean plate. Geological and geopysical data allow locating this volcanic arc and the associated subduction zone back in time (light thin yellow lines), through the Miocene (M), Oligocene (O), Eocene (E), Paleocene (P), Upper Cretaceous (UC) and Lower Cretaceous (LC), when the arc was located at a position similar to that of the present-day Central American volcanic arc. This indicates that the Caribbean Plate formed at the Pacific and drifted, relative to the Americas, towards the East during the Mesozoic and the Tertiary (light thick yellow arrow). During this trip, the volcanic arc, which has been called the “Great Arc of the Caribbean”, faced and collided with the continental margins of the Yucatan block, the Bahamas and South America during the uppermost Cretaceous and Tertiary (light blue curved arrows). The rocks documenting subduction zones in the peri-Caribbean orogenic belt formed during the Cretaceous and Tertiary. |
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Understanding the evolution of the Caribbean realm needs understanding the fragmentation of Pangea and formation of oceanic basins in the region. In short, the following events can be established:
It is apparent that, because the volcanic arc activity started in the mid-Cretaceous (pre?-Aptian) when NA and SA were drifting away, the Caribbean arc can hardly be conceptualized as a result of NA-SA convergence. As a consequence, it follows that an oceanic basin (the Proto-Caribbean) should have formed in between the Americas during 180-70 Ma, and that the Caribbean plate must be exotic with respect to its present position in between the Americas. |
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Reconstruction of the relative motion of South America with respect to North America. Mesozoic divergence should have formed an oceanic basin in between (the Proto-Caribbean). |
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Reconstruction of the relative motion of South America with respect to North America. Mesozoic divergence should have formed an oceanic basin (the Proto-Caribbean) in between the Americas. The small convergence rate since the Tertiary cannot explain the development of the Caribbean arc (volcanic activity started at ca. 130 Ma). |
In general, most authors agree in a) formation of an oceanic inter-Americas gap (i.e., Proto-Caribbean) during Jurassic break-up of Pangea and Cretaceous drift of North and South America, b) progressive consumption of the Proto-Caribbean during the Cretaceous-Tertiary in one or several subduction zones, c) insertion of the Pacific derived Caribbean plate into the inter-Americas gap and d) collision of the Caribbean plate with the North and South American plate margins during the uppermost Cretaceous and Tertiary (Wilson, 1966; Malfait and Dinkelman, 1972; Mattson, 1979; Pindell and Dewey, 1982; Burke et al., 1984; Duncan and Hargraves; 1984; Burke, 1988; Pindell and Barrett, 1990; Pindell, 1985, 1994; Iturralde-Vinent, 1998; Kerr et al., 1998, 1999; Mann, 1999; Pindell and Kennan, 2001; see complete references in García-Casco el al., 2006)). This process may have been accompanied by a change in polarity of subduction, from eastward-dipping subduction of the Pacific below the Proto-Caribbean to westward-dipping subduction of the Proto-Caribbean below the Pacific (Caribbean), but the age and tectonic scenario of the flip is debated.
Burke (1988), Duncan and Hargraves (1984) and Kerr et al. (1998) have argued for an Upper Cretaceous flip of subduction, while Mattson (1979), Pindell and Dewey (1982), Pindell (1994) and Pindell and Kennan (2001) have proposed an Aptian age. Mid-Cretaceous unconformities recorded in volcanic arc sequences along the Antilles and Venezuela have been related to an important mid-Cretaceous orogenic event by Pindell and Kennan (2001). Lebron and Perfit (1993, 1994) argued for a mid-Cretaceous flip based on an abrupt change from IAT to CA affinity in volcanic arc rocks, but this argument has been disputed by Kerr et al. (1999), Jolly et al. (2001). Mid-Cretaceous reversal of subduction has been related to northward overthrusting of the arc by oceanic crust in the Cordillera Central of Hispaniola (Draper et al., 1996, Lewis et al., 1999, 2002), but according to Lapierre et al. (1997, 1999) this tectonic event took place in Upper Cretaceous times.
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A reconstruction by Pindell, J.L. & Kennan, L., (2001. Kinematic Evolution of the Gulf of Mexico and Caribbean. In: Fillon, R., Rosen, N.,Weimer, P., Lowrie, A., Pettingill, H., Phair, R., Roberts, H., van Hoorn, B. (eds.). Transactions of the Gulf Coast Section Society of Economic Paleontologists and Mineralogists (GCSSEPM) 21st Annual Bob F. Perkins Research Conference, Petroleum Systems of Deep-Water Basins, Houston, Texas, 193-220; download pdf file; also visit http://www.tectonicanalysis.com/site/download/default.htm) is given below. Note that, in this model:
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The issue of the plate tectonic evolution of the Caribbean is hot, and studies of subduction-related metamorphic rocks do certainly add to this debate.
last modified: 01.04.08 23:36 +0100
