Abstract

The active margin of Gondwana is presently preserved in the southwest Pacific region in the formerly continuous Gondwana fragments of Australia, Antarctica and New Zealand. The Phanerozoic tectonic history of New Zealand is interpreted in terms of progressive Pacific-ward growth by accretion of arc-trench systems and the basement rocks are described in terms of a number of volcano-sedimentary accreted terranes, suites and batholiths that intrude the terranes. The age of these basement rocks ranges from Early Cambrian to late Early Cretaceous. The origin of the magmatic and sedimentary rocks and the time of accretion of the New Zealand terranes to the Gondwana margin are important for the understanding of Phanerozoic Pacific tectonics. Geochronological research over the last decade on igneous rocks and conglomeratic units shows that the Tutoko Complex/Amundsen Province plutons are major contributors of detritus to the Pahau depositional basin and that the Antarctic sector of the Panthalassan Gondwana margin has to be (re)considered as the likely source for the Permo-Triassic Rakaia sediments. Igneous clast data have greatly improved understanding of the evolution of the New Zealand microcontinent and have put tighter constraints on its Mesozoic tectonic setting within the southwest Pacific margin of Gondwana.