The ultramafic—mafic complex at North Cape, northernmost New Zealand

Abstract

The ultramafic—mafic complex at North Cape lies in a Mesozoic—Lower Tertiary tectonic belt linking New Zealand with New Caledonia and Papua New Guinea. The complex is faulted against Cretaceous submarine tholeiites and contains (1) serpentinized harzburgite and lherzolite of probable cumulus origin (and intruded by more Fe-rich wehrlitic veins and dykes), overlain by (2) layered olivine- and orthopyroxene-gabbro subvolcanic cumulates which are themselves host for (3) a sheeted dyke swarm of mainly quartz-diorite composition. It is suggested that the complex was emplaced with the Cretaceous volcanics by obduction of Mesozoic oceanic crust during the Lower Tertiary.