The continental crust covers an area of the southwest Pacific Ocean measuring 4.9 Mkm2. The area contains higher bathymetry than the oceanic crust around it, a variety of rocks rich in silica, and a relatively thick, slow-moving crustal structure. Both its distance from Australia and its size support Zealandia’s classification as a continent. Formerly, Zealandia belonged to Gondwana. As a result of widespread Late Cretaceous crustal thinning that occurred before supercontinent breakup and the ensuing isostatic balance, it is 94% underwater now. It is more accurate to refer to Zealandia as a geological continent as opposed to a group of continental islands, shards, and slices to describe this region of Earth’s geology. Zealandia offers a novel environment for studying the thinning, breaking up, and rifting of continents. The southwest Pacific Ocean contains the sizable, uninhabited islands of New Zealand and New Caledonia. Although the geographic term Australasia is frequently used to refer to the region’s land mass and islands in the southwest Pacific, they have never been considered a part of the Australian continent. We review the four essential characteristics of continents in the sections that follow and evaluate how well Zealandia satisfies these requirements. Although the height of continents and their continental shelves can vary, they are always elevated in relation to the oceanic crust. The density and thickness of the lithosphere, as well as plate tectonics, are two key factors that affect elevation. More than a century has passed since the discovery of positive bathymetric features north and south of New Zealand.
