North Caribbean neotectonic events: The Trans-Haitian fault system. Tertiary record of an oblique transcurrent shear zone uplifted in Hispaniola

Abstract

The left-lateral relative motion between the Caribbean and the North American plates has previously been inferred as occurring along a fault zone located north of Hispaniola. East of the northern Dominican Republic, a relatively linear fracture zone (the Septentrional Fault Zone, SFZ) extends into the Puerto Rico subduction zone. Similarly, south of Haiti, the trace of the inactive Enriquillo-Plantain Garden Fault Zone (EPGFZ) extends into the Muertos Trench and may represent a major fault along the plate boundary. Between these two major strike-slip fault systems, the central part of Haiti shows a diffuse fracture zone that trends N130. The chronology of deformation involves an initial Paleocene to Eocene suturing of allochthonous terranes, a Late Miocene development of a strong spaced cleavage within the late Paleocene to Late Miocene strata that overlap the terrane suture, and diffuse Pliocene to Pleistocene strike-slip faulting along traces that reactivate the older spaced cleavage planes. During the Pleistocene, basalts ranging in age from 0.4 to 1.3 Ma were extruded in pull-apart basins associated with N130-trending faults (antithetic features of the SFZ) and N30 normal faults (antecedent synthetic features of the SFZ). This event is coeval with the compression recorded at the Muertos-Beata collision front in the southwestern Dominican Republic. The most recent phase of tectonism involves strong uplifts and broad, open folding along NW-striking axes, which is consistent with the regional maximum deformation pattern predicted for E-W left-lateral shear along the North America—Caribbean plate boundary.