10.6084/m9.figshare.3454685.v1
Alan R. Hastie
Alan R.
Hastie
Andrew C. Kerr
Andrew C.
Kerr
Simon F. Mitchell
Simon F.
Mitchell
Ian L. Millar
Ian L.
Millar
Geochemistry and tectonomagmatic significance of Lower Cretaceous island arc lavas from the Devils Racecourse Formation, eastern
Jamaica
Geological Society of London
2016
CA mantle wedge source regions
slab fluxes
earth element ratios
lava succession
IAT
Devils Racecourse Formation
Jamaica
island arc tholeiite
basaltic portion
trace element
Benbow Inlier
Nd
Great Arc
mantle wedge source regions
CA lavas
tectonomagmatic significance
subduction
CA island arc lavas
Aptian island arc succession
evidence
Cretaceous island arc lavas
basaltic andesites
basaltic andesite sequence
Geology
2016-06-21 12:17:28
Journal contribution
https://geolsoc.figshare.com/articles/journal_contribution/Geochemistry_and_tectonomagmatic_significance_of_Lower_Cretaceous_island_arc_lavas_from_the_Devils_Racecourse_Formation_eastern___Jamaica/3454685
<p>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*)<sub><em>n-mn</em></sub> 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.
</p>