Abstract The Benbow Inlier in Jamaica contains the Devils Racecourse Formation, which is composed of a Hauterivian to Aptian island arc succession. The lavas can be split into a lower succession of basaltic andesites and dacites/rhyolites, which have an island arc tholeiite (IAT) composition and an upper basaltic and basaltic andesite sequence with a calc-alkaline (CA) chemistry. Trace element and Nd–Hf isotopic evidence reveals that the IAT and CA lavas are derived from two chemically similar mantle wedge source regions predominantly composed of normal mid-ocean ridge-type spinel lherzolite. In addition, Th-light rare earth element/high field strength element–heavy rare earth element ratios, Nd–Hf isotope systematics, (Ce/Ce*) n-mn and Th/La ratios indicate that the IAT and CA mantle wedge source regions were enriched by chemically distinct slab fluxes, which were derived from both the altered basaltic portion of the slab and its accompanying pelagic and terrigenous sedimentary veneer respectively. The presence of IAT and CA island arc lavas before and after the Aptian–Albian demonstrates that the compositional change in the Great Arc of the Caribbean was the result of the subduction of chemically differing sedimentary material. There is therefore no evidence from the geochemistry of this lava succession to support arc-wide subduction polarity reversal in the Aptian–Albian. Supplementary material: References for data sources used in figures can be found at: http://www.geolsoc.org.uk/SUP18361.

Abstract The Early Cretaceous island arc lavas in the Caribbean region are frequently assigned to the primitive island arc (PIA) series and not to the island arc tholeiite (IAT) series. However, this review demonstrates that the Caribbean PIA rocks have immobile trace element abundances, trace element ratios and Nd–Hf isotope systematics which are indistinguishable from modern IAT lavas. Thus, it is proposed that the term PIA series be discarded and that the Early Cretaceous island arc rocks in the Caribbean be classified as IAT rocks. Supplementary material: References for data sources used in figures can be found at: http://www.geolsoc.org.uk/SUP18362.