Zealandia, a submerged piece regarded as the eighth continent on Earth, has long baffled the efforts of experts. GNS Science geologist Andy Tulloch and his team designed an updated map of that region by using geochemical and isotopic data from newly excavated samples of rocks in addition to seismic readings. Their goal was to study how the continent came into being using this information.
Research insights
A subduction of Zealandia’s edge may have occurred as recently as a quarter of a billion years ago throughout what is now the Campbell Plateau off the coast of New Zealand. This was determined through an examination of rock samples from Chatham and Antipodes islands, some of which date back to the time of the dinosaurs. That’s very remarkable, don’t you think?
When two edges of the Earth’s crust press against one another, the process known as subduction occurs. This causes one edge to descend into the Earth’s mantle. However, contrary to what was said before, the magnetic anomalies that were discovered in the exact location are not associated with this event.
The researchers hypothesize that the Campbell Magnetic Anomaly System came into being as a result of substantial stretching that occurred between various regions of Gondwana before it finally broke apart to form the sea levels that encircle Zealandia.
New Zealand and the islands that surround it are the only landmasses that are now visible above the surface of the water; thus, Zealandia is still a vast mystery. Because water covers around 94 percent of the 4.9 million km2 continent, information regarding the northern portion of the land mass remains hidden but awaiting.
Tulloch and his colleagues discovered evidence that suggests the direction of stretching changed by as much as sixty-five degrees between 100 and 80 million years ago. They believe that this may have been what allowed for the significant weakening of the crust of the continent. The research is still ongoing.
