Enviroment

Zealandia; the new continent?

An international team under the supervision of David Sandwell, an oceanographer at the Scripps Institution of Oceanography in California, published a highest-resolution gravity map of the sea-floor using the obtained data of CryoSat-2 and CNES satellites, in the 3 October 2014 issue of Science. This map provides a lot of valuable data such as oceanic crustal plates movements. It can resolve sea-floor features to about 5 kilometres, which is enough to discover a seamount but not enough to pinpoint smaller features.

In the beginning of 2017, a team lead by Nick Mortimer the geologist at GNS Science in Dunedin, announced a new continent; Zealandia. It is a region spanning 5 million square kilometers, which includes New Zealand and New Caledonia, a single and intact piece of continental crust which is geologically separateed from Australia. It seems that Zealandia would probably long ago have been recognized as a continent. The obtained map from Earth’s gravitational field clearly show that Zealandia is a coherent geographical feature expanding from near Australia’s northeastern coast well past the islands of New Zealand.  Sea-floor samples reveal that Zealandia consists of light continental crust and not the dark volcanic rocks that make up nearby underwater plateaus. The area seems to be structurally intact, rather than a mash-up of different continental-crust fragments.

 

References:

1- Mortimer, N. et al. GSA Today http://dx.doi.org/10.1130/GSATG321A.1 (2017).

2- http://www.nature.com/news/geologists-spy-an-eighth-continent-zealandia-1.21503

3- Sandwell, D. T. et al. Science 345, 65–67 (2014).


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Saturday 18 February 2017