Mapping Zealandia: Scientists explore the seabed off the coast of Australia in hopes of unraveling the mystery of Earth’s ‘hidden’ eighth continent that sank into the sea 23 million years ago
- The ‘lost’ continent of Zealandia was first identified by geologists in 2014
- Australian and American experts mapped the depths in northwestern Zeeland
- The team collected a total of 4,286 square miles of bathymetric data
- It will be used by the Seabed 2030 project to create a map of the world’s oceans
Scientists have explored the seafloor off Australia to unravel the mystery of Zealandia, the “lost” eighth continent that sank into the sea 23 million years ago.
The largely submerged continent – of which New Zealand and New Caledonia remain above the waves – was first identified by geologists in 2014.
Australian and American experts have just spent 28 days at sea on the Falkor research vessel, which maps the depth of the seabed on the northwestern edge of Zealand.
They collected 37,000 square miles of bathymetric data that they provided to the Seabed 2030 project.
This aim is to produce a publicly available bathymetric map of the entire world’s ocean floor by the year 2030.
Scientists have explored the seabed off Australia to unravel the mystery of Zealandia, the ‘lost’ eighth continent that sank 23 million years ago
Australian and American experts have just spent 28 days at sea on the research vessel Falkor (photo, with expedition leader Derya Gürer in the foreground) mapping the depth of the ocean floor on the northwestern edge of Zealand, in the Coral Sea Marine Park
“We’re just beginning to discover the secrets of Zeelandia – it remained hidden in plain sight until recently and is notoriously difficult to study,” said expedition leader and geologist Derya Gürer of the University of Queensland.
“Zealandia is an almost completely submerged mass of continental crust that subsided after breaking from Gondwanaland 83 to 79 million years ago.”
Gondwanaland is the name given to the supercontinent that encompassed landmasses we would recognize as South America, Africa and Antarctica.
It formed about 550 million years ago before becoming part of the greater Pangea supercontinent and disintegrating about 180 million years ago.
Zealandia, continued Dr. Gürer, “covers 4.9 million square kilometers [1.9 million square miles] and is about three times the size of Queensland. ‘
“Our expedition collected topographic and magnetic data on the seafloor to gain a better understanding of how the close connection between the Tasman Sea and the Coral Seas in the Cato Trough region, the corridor between Australia and Zealandia, was formed.”
‘The seabed is full of clues for understanding the complex geological history of both the Australian and Zeeland continental plates.’
“These data will also improve our understanding of the complex structure of the crust between the Australian and Zeeland plates.”
“It is thought to include several small continental fragments or microcontinents that split off from Australia and the supercontinent Gondwana in the past.”
The largely submerged continent – of which New Zealand and New Caledonia remain above the waves – was first identified by geologists in 2014. Pictured, a tectonic map of the 1,930,511 square mile continent of Zealandia, of which only one small part on land. On the map, the continental crust is shown in red, orange, yellow and brown tones, while the oceanic crust is shaded in blue. The volcanic island’s arc crust is pink, while the great igneous provinces are green
While conducting their bathymetric survey at the Coral Sea Marine Park, the researchers also took the opportunity to study seabirds and also check for ocean-borne microplastic pollution. Pictured: The researchers sampled for microplastics in the wet lab
While conducting their bathymetric survey at the Coral Sea Marine Park, the researchers also took the opportunity to study seabirds and also check for ocean-borne microplastic pollution.
“Through the ship’s seawater flow-through system, we analyzed more than 100 samples for microplastics, in addition to 40 samples collected from a previous voyage,” said earth scientist Tara Jonell, also from the University of Queensland.
“Only one sample contained no visible microplastic,” she added.
According to Dr. Gürer – who is also involved in a citizen science project to tackle plastic pollution at sea – there was a clear message in the seawater, which was collected to a depth of 3.5 kilometers.
“There appears to be a higher concentration of microplastic fibers in the deep ocean,” she explained.
ZEALANDY: EARTH ‘LOST’ EIGHTH CONTINENT
Pictured, the continent Zealandia
‘Zealandia’ – also known as ‘Te Riu-a-Māui’ in te reo Māori – is a largely submerged mass continental crust.
Zealandia sank when it split off from the supercontinent Gondwanaland some 83-79 million years ago.
The concept of Zealandia was first proposed in 1995, but was not recognized as a continent in its own right until 2017.
It is twice the size of the largest microcontinent and also meets the continental criteria for the thickness and density of the Earth’s crust.