The transgressive sedimentary sequence of the Noumea Basin
contains rhyolitic lavas and less voluminous mafic and intermediate volcanics of
shoshonitic affinities which erupted simultaneously during the late Cretaceous.
The shoshonitic volcanism shows a trend froIn early mafic to younger evolved
intermediate lithologies. The rhyolites are consistently calcalkaline. There is
no evidence of mixing of the two magma types. The shoshonitic volcanism is the
result of a short-lived subduction event related to spreading in the New
Caledonia Basin and involved reactivation of an earlier esozoic
subduction
zone.