Thrust emplacement of the Hispaniola peridotite belt : orogenic expression of the mid-Cretaceous Caribbean arc polarity reversal?

Abstract

New structural data from central Hispaniola suggest that a mid-Cretaceous orogenicevent resulted in the obduction of peridotites onto the early Antillean arc. The MaimoŽn belt,which structurally underlies the peridotites, contains a shear zone composed of myloniticand phyllonitic schists formed by northward thrust emplacement of the peridotites. Penetrativedeformation decreases progressively to the northeast and is observed in the Neocomiansedimentary and volcanic rocks of the Los Ranchos Formation. The unconformablyoverlying, upper Albian Cenomanian limestones are not penetratively deformed, thusbracketing the obduction to Aptian-Albian time. This event is synchronous with chemicalchanges of the arc magmas in Hispaniola, Puerto Rico, and central Cuba. Thus, they mayboth be related to the postulated Greater Antillean polarity reversal.