Geochemistry and tectonomagmatic significance of Lower Cretaceous island arc lavas from the Devils Racecourse Formation, eastern Jamaica
Hastie, Alan R.; Kerr, Andrew C.; Mitchell, Simon F.; Millar, Ian L.. 2009 Geochemistry and tectonomagmatic significance of Lower Cretaceous island arc lavas from the Devils Racecourse Formation, eastern Jamaica. In: James, K.H.; Lorente, M.A.; Pindell, J.L., (eds.) The origin and evolution of the Carribean plate. London, UK, Geological Society of London, 339-360. (Geological Society Special Publications, 328).Full text not available from this repository. (Request a copy)
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.
|Item Type:||Book Section|
|Programmes:||BGS Programmes 2009 > NERC Isotope Geoscience Laboratory|
|NORA Subject Terms:||Earth Sciences|
|Date made live:||21 May 2010 09:20|
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