Hispaniola consists of an agglomeration of 11 island-arc terranes that crop out over the northern two-thirds of the island and one oceanic plateau terrane that crops out over the southern one-third of the island. The island-arc terranes, which range in age from Early Cretaceous to late Eocene, can be classified on the basis of lithologic associations, structure, and metamorphic grade as: (1) fragments of oceanic crust, (2) fragments of the fore arc/accretionary prism of an island arc, (3) fragments of the volcano-plutonic part of an island arc, and (4) a fragment of a back-arc basin.
The structure and stratigraphy of the volcano-plutonic and fore-arc/accretionary prism arc terranes of Hispaniola suggest eight main tectonic phases: (1) earliest Cretaceous to pre-Aptian island-arc plutonism, volcanism, and metamorphism mainly in a submarine environment; (2) pre-Aptian uplift and erosion of the island arc in eastern Hispaniola and Puerto Rico possibly associated with arc collision and a subsequent reversal in subduction polarity of the island arc; (3) post-Albian to pre-Campanian renewal of island-arc plutonism, volcanism, and metamorphism mainly in a submarine environment; (4) Campanian deformation and metamorphism possibly associated with a second arc collision and subsequent reversal in subduction polarity of the island arc; (5) post-Campanian to pre-middle Eocene renewal of island-arc plutonism, volcanism, and metamorphism mainly in a submarine environment; (6) middle to early late Eocene collision of the island arc with the southern edge of the North America plate (Bahama carbonate platform); collision uplifted the submerged arc and terminated island-arc volcanism and plutonism; (7) east-west strike-slip faulting subparallel to the strike of partially emerged and eroding arc rocks beginning in the Eocene and lasting to the early Miocene; and (8) early Miocene transpression resulting from oblique collision and suturing of the oceanic plateau terrane with the island-arc terrane and interaction of east-west strike-slip zones with older north-northwest island-arc structures. Many of the terrane boundaries separating island-arc and oceanic plateau terranes were reactivated as oblique-slip faults during early Miocene to Recent convergence between the island-arc and oceanic plateau terranes and form nine morphotectonic provinces consisting of elongate, fault-bounded mountain ranges and intervening clastic sedimentary basins.
The structure and stratigraphy of the oceanic plateau terrane suggests four main tectonic phases: (1) Late Cretaceous oceanic plateau growth; (2) Latest Cretaceous deformation and erosion; (3) Paleocene-early Miocene subsidence and strike-slip faulting; and (4) early Miocene to present transpression.
The discrepancy between large-scale strike-slip offset along the Cayman Trough (~1,110 km) and much smaller offsets of arc rocks in Hispaniola and Central America (<200 km) is explained by the existence of restraining bends along interplate strike-slip faults in Hispaniola and Central America, which locally transform strike-slip displacement into fault splays, rotation of fault-bounded blocks, vertical uplift, or underthrusting. Based on indirect regional constraints, we infer that both the oceanic and island-arc terranes of Hispaniola originated in the Pacific as part of a single continuous island arc, the “Great Arc,” which swept into the Caribbean during Late Cretaceous and early Cenozoic time.
