Continental drift Permian era but failing to account for glaciation in India, Australia and South Africa. Geophysicist Jack Oliver is credited with providing seismologic evidence supporting plate tectonics which encompassed and superseded continental drift with the article "Seismology and the New Global Tectonics", published in 1968, using data collected from seismologic stations, including those he set up in the South Pacific. It is now known that there are two kinds of crust: continental crust and oceanic crust. Continental crust is inherently lighter and its composition is different from oceanic crust, but both kinds reside above a much deeper "plastic" mantle. Oceanic crust
Drift to the north Recent censuses have shown a slowing of the rate of drift, with increasing numbers of North Islanders heading to the South Island's popular scenic regions such as Central Otago. Drift to the north Drift to the north is a term used in New Zealand to refer to the internal migration of people from the South Island to the country's main metropolitan area, Auckland, in the northern North Island. The term is especially common in the cities of Christchurch and Dunedin, university cities whose graduates frequently head either to Auckland or the country's capital Wellington (also in the North Island) after