Scientists have discovered a lost continent deep in the southern arm of the Arctic Ocean that was formed 60 million years ago.
Researchers at the University of Derby in the UK discovered the 400-kilometer-long landmass beneath the Davis Strait between Canada and Greenland by chance while studying the plate tectonic movements of the area.
The newly discovered proto-microcontinent in the Davis Strait, a tectonic block that broke away from a continent, was formed “by a prolonged period of seafloor splitting and spreading between Greenland and North America,” the researchers explained.
The team suspects that the proto-microcontinent broke away from Greenland after tectonics between the country and Canada caused it to split into two parts about 118 million years ago.
Scientists have discovered a submerged microcontinent between Canada and Greenland that was formed 60 million years ago. Pictured: The Davis Strait, where the microcontinent was discovered
Researchers from the University of Derby reconstructed the plate tectonic movements of the area when they discovered a thick crust stretching for nearly 250 miles beneath the Davis Strait. Pictured: The Davis Strait proto-microcontinent lies underwater in the Davis Strait
“Rifting and the formation of microcontinents are absolutely ongoing phenomena – with every earthquake we could be working towards the next microcontinent breakaway,” Dr. Jordan Phethean told Phys.org.
“The aim of our work is to understand their origins so well that we can predict exactly this future development.”
The researchers identified the new microcontinent using a combination of crustal thickness data from gravity maps, seismic reflection data, and plate tectonics models.
Gravity maps contain information on rock density as well as the depth and distribution of anomalous source rocks.
The team focused on the formation of the crustal anomaly by reconstructing tectonic movements that lasted about 30 million years.
They described the proto-microcontinent as larger than other microcontinents, ranging from 17 to 22.5 kilometers thick, and said understanding its formation is crucial to today’s science.
The average microcontinent is typically between 5 and 24 kilometers thick.
The mapping techniques tracked how seafloor movements had changed over millions of years and identified “an isolated terrane of relatively thick continental crust that was formed during a newly recognized phase of [the east to west] Expansion along West Greenland,” the study says.
Researchers said the Davis Strait is one of the largest concentrations of known fault structures with clearly defined changes in plate motion that could help understand the formation of microcontinents.
Proto-microcontinents are part of the continental lithosphere, a section of the Earth’s outer crust that is divided into several tectonic plates – rock plates.
About 80 to 190 kilometers below the Earth’s surface there is a semi-liquid layer of rock that is heated and then melted, causing the rock to begin to flow.
The movement causes the tectonic plates to shift, causing them to rub against each other over millions of years, resulting in earthquakes and volcanic eruptions.
When this happens, the land mass separates from the major continents and a separate proto-microcontinent is formed.
Proto-microcontinents are part of the continental lithosphere, a section of the Earth’s outer crust that is divided into several tectonic plates – rock plates. Pictured: Movement of tectonic plates over millions of years
The research team used maps created from gravity and seismic reflection data showing images of the Earth’s subsurface, using sound waves to determine the age and location of fault lines. Pictured: An overview of the tectonic plates in the Davis Strait
The first split between Canada and Greenland began about 118 million years ago, but it was not until 61 million years ago that the sea floor began to expand, creating what is now the Davis Strait.
After about three million years, scientists reported, the spreading of the sea floor shifted from northeast-southwest to north-south, causing the proto-microcontinent of the Davis Strait to break off.
The shift lasted about 33 million years and was only ended by the collision of Greenland with Ellesmere Island to the north.
The researchers hope their findings can help understand the formation of other proto-microcontinents around the world, including the Jan Mayen microcontinent northeast of Iceland and the Gulden Draak Knoll off the coast of Western Australia.
“Rifting and microcontinent formation are absolutely ongoing phenomena – with every earthquake we could be working toward the next microcontinent breakaway,” Phethean told Phys.org.
“The aim of our work is to understand their origins so well that we can predict exactly this future development.”