Monday, June 22, 2020

Maps with Zealandia

The vast majority of the continent of Zealandia sank beneath the oceans around 23 million years ago. Originally Zealandia was part of the supercontinent Gondwana (along with South America, Antarctica, India, Australia, Arabia and Africa). Zealandia broke away from Gondwana between 83–79 million years ago. The vast majority of it now sits beneath the Pacific Ocean and Tasman Sea. Only the islands of New Zealand and New Caledonia remain above sea level.

It is only in the past decade that Zealandia has begun to be classified as a continent in its own right. You can now explore a number of interactive maps of Zealandia thanks to GNS Science’s Te Riu-a-Māui / Zealandia research programme (TRAMZ). Their new E Tūhura - Explore Zealandia mapping portal allows you view the whole of Zealandia - even the 94% of it which now lies at the bottom of the sea.

The interactive maps featured in E Tūhura, include a tectonic map (showing the plate and microplate boundaries of Zealandia), a bathymetry map (showing the shape of both solid land and the seabed) and a geoscience data map (featuring a number of different GIS map layers).

During the Early Permian period, Gondwana collided and joined with Euramerica (a paleocontinent made up of south Europe and North America) to create the super-continent Pangea. Pangea existed during the late Paleozoic and early Mesozoic eras, before it began to break apart about 175 million years ago. Of course there weren't any country borders on Pangea. However the land mass that was Zealandia would probably have been attached to what we now know as Australia

Pangaea Politica by Massimo Pietrobon is an interesting (if fanciful) map which overlays modern country borders on a map of Pangea. The map is at best a guesstimate of where modern countries might have been on Pangea. There are some obvious errors, for example the map includes the country of Iceland, a volcanic island which didn't exist when Pangea was around. However it is still good fun to imagine which modern countries might share borders today if Pangea had never broken apart.

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