2023-09-26 08:05:48
Approximately 23 million years ago, a momentous event occurred in the geological history of our planet: Zealandia, which was emerging as the eighth continent, It was 95% submerged under ocean waters, after separating from the supercontinent Gondwana about 60 million years ago.
What we know today as New Zealand, New Caledonia and its surrounding islands are the only portions of Zealandia that emerge above the ocean surface, leaving much of this continent mired in a mystery.
Science has revealed some aspects of Zealandia
Despite this enigma, The science has managed to shed light on certain aspects of Zealandia. We know that its crust is thinner than that of most continents, although thicker than oceanic crust. It was formed during the fracture of Gondwana, when the crust was thinned and stretched.
Additionally, it has been confirmed that Zealandia was home to a varied fauna and flora in the past, thanks to evidence such as pollen spores from land plants and remains of shallow sea creatures, now hidden under the ocean.
Precise origin of your weight loss
However, the exact cause of his weight loss remained a mystery. For this reason, researchers have recently completed cartography and have created a detailed map of the northern two-thirds of Zealandia to study how this continent was formed, thus completing the documentation of the almost three million square kilometers of submerged land mass.
In a study published in Tectonics, Scientists from GNS Science in New Zealand describe their process of collecting rock samples from the Fairway Ridge to the Coral Sea in order to analyze the rock’s geochemistry and understand the underwater composition of Zealandia.
“This work completes the offshore survey geological mapping of the entire continent of Zealandia,” the researchers said.
The scientists found sandstone dating back about 95 million years, from the Late Cretaceous, and a combination of granite and volcanic pebbles that are up to 130 million years old, also from the Late Cretaceous. The basalts are more recent, with an age of approximately 40 million years, during the Eocene.
The sinking of the continent Zealandia
According to the team, between 100 and 80 million years ago, a significant thinning of the crust occurred that culminated in the collapse of the continent, probably due to its stretching in several directions.
In particular, the paper notes that the internal deformation of both Zealandia and West Antarctica indicates that stretching led to the formation of cracks similar to those associated with the subduction of tectonic plates, allowing ocean water to break through to create the Tasman Sea. Subsequently, a new fracture in Antarctica continued to stretch Zealandia’s crust until it thinned enough to fracture and become largely submerged.
This contradicts the prevailing theory of a rupture caused by slip.
According to Science Alertthe team of scientists suggests that the direction of stretching varied by up to 65 degrees, which may have facilitated extensive thinning of the continental crust.
Edited by Felipe Espinosa Wang.
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