Middle Cretaceous Nappe Structures in Puerto Rican Ophiolites and Their Relation to the Tectonic History of the Greater Antilles

Serpentinization history of the Río Guanajibo serpentinite body, Puerto Rico

“…The Early Cretaceous emplacement of the SBSB was due to either: (1) a subduction polarity reversal event (Mattson, 1973;Mattson and Pessagno, 1979;Pindell, 1994) or (2) by contraction in the back arc of the island arc during continuous SeW dipping (Krebs et al, 2011;L azaro et al, 2009;Pindell et al, 2012;La o-D avila, 2014). The emplacement of the RGSB and the MDESB, during the Late-Cretaceous-Paleocene, is associated with a collision of the northern Caribbean subduction zone and a hypothesized Caribeana-submerged platform to the north (García-Casco et al, 2008).…”

“…Serpentinites in southwestern Puerto Rico resemble abyssal serpentinites (Lewis et al, 2006b;Marchesi et al, 2011), although Jolly et al (2008) suggest that supra-subduction zone processes affected some of the serpentinite samples within the Río Guanajibo Belt. The emplacement of the central Hispaniola and Puerto Rico serpentinized peridotite sequences occurred due to thrusting onto arc crust in response to crustal shortening (Dilek, 2003;Lewis et al, 2006b;La o-D avila et al, 2012) during the Cretaceous (110e120 million years ago; Mattson, 1973;Mattson and Pessagno, 1979). During the Late Eocene, transpressional movement reactivated preexisting faults and resulted in the uplift and exposure of the serpentinite bodies in Puerto Rico and Hispaniola (La o-D avila et al, 2012;Lewis et al, 2006b).…”

Cretaceous-Paleogene thrust emplacement of serpentinite in southwestern Puerto Rico

“…This study focuses on the Monte del Estado and Río Guanajibo bodies because they are well exposed over a large area, as opposed to the mostly covered serpentinite in Sierra Bermeja. Mattson (1973) and Schellekens (1998) proposed that Sierra Bermeja is an ophiolitic mélange composed of folded chert, serpentinite, amphibolite, gneiss, schist, and metabasalt. Mattson (1973) invoked the southwest dip of axial planes in folded chert, and of foliation in schist and serpentinite, to argue in favor of an emplacement as a north-directed thrust nappe during obduction.…”

“…Mattson (1973) and Schellekens (1998) proposed that Sierra Bermeja is an ophiolitic mélange composed of folded chert, serpentinite, amphibolite, gneiss, schist, and metabasalt. Mattson (1973) invoked the southwest dip of axial planes in folded chert, and of foliation in schist and serpentinite, to argue in favor of an emplacement as a north-directed thrust nappe during obduction. Mattson and Pessagno (1979) and Pindell (1994) attributed the obduction of the serpentinite mélange to Early Cretaceous collision of the Caribbean plate and the protoCaribbean lithosphere.…”

Multichannel seismic measurements on the northern edge of the Bahaman-Cuban collision zone

“…Wassail (1957) adds knowledge of the range of structural styles extant on the island by describing the role of block faulting associated with uplift, subsequent to thrusting. Mattson (1973) According to Mattson (1973), left-lateral strike-slip motion in the Cayman…”