Arc-continent collision forming a large island between New Caledonia and New Zealand in the Oligocene

Abstract

Dredge samples from the Three Kings Ridge between New Caledonia and New Zealand revealed the presence of an old collisional orogen. The samples included 38 Ma high-P metamorphic rocks, mantle peridotite, probably from the forearc of an island arc, and continental-derived rocks with old Gondwana-derived zircons and fossil leaves. The samples suggest that a large island existed to the east of the Three Kings Ridge between 38 Ma and 21 Ma, when extension associated with the opening of the South Fiji basin caused the island to subside below sea level.