Migration of late Cenozoic volcanism in the South Island of New Zealand and the Campbell Plateau

Abstract

In late Cenozoic volcanics of eastern Australia, Wellman and McDougall¹ have shown a remarkable southward migration pattern of major shield volcanoes of alkaline olivine basalt association which they relate to movement of the continental crust over a fixed mantle hot-spot. Contemporaneous tholeiite lava field provinces do not show a similar pattern. Following their general selection criteria¹, I believe a similar situation emerges for New Zealand examples. In the South Island of New Zealand and the adjacent Campbell Plateau and Chatham Rise are several late Cenozoic volcanic centres that rest on a peneplain in Mesozoic and Palaeozoic granites and metamorphic rocks^2,3, which is partly mantled by late Cretaceous to mid-Tertiary shallow marine sediments^4,5. These major centres of late Cenozoic alkalic volcanism show an eastward decrease in age from ∼28 Myr to ∼0.5 Myr, presumably reflecting movement of a linear mantle source with respect to the Pacific Plate.