Lost continent discovered that formed 60 million years ago!
Researchers at the University of Derby in the UK have accidentally discovered a landmass more than 400 kilometres long beneath the Davis Strait, between Canada and Greenland, while studying the tectonic movements of plates in the region.
The researchers noted that the newly discovered Davis Strait protocontinent, a tectonic block that became a separate continent, was formed during "a long period of rifting in the seafloor between Greenland and the North American continent".
Discovery of a minicontinent
"The rifting and the formation of the minicontinent are completely ongoing phenomena, with every earthquake," Dr. Jordan Fithian told the physics website "Phys.org".
The researchers identified the new minicontinent using a combination of crustal thickness data derived from gravity maps, seismic reflection data, and plate tectonics modeling.
The gravity maps contain information about the density of rocks and the depth and distribution of anomalous source rocks.
The team focused on how the crustal anomaly formed by reconstructing tectonic movements that lasted for about 30 million years.
They described the proto-microcontinent as larger than other microcontinents, measuring between 17 and 23 kilometers thick, and said understanding how it formed is vital to ongoing science today.
The average thickness of a microcontinent is typically between 5 and 25 kilometers.
Mapping techniques tracked how seafloor movements changed over millions of years and identified “an isolated landmass with relatively thick continental crust that broke away from Greenland during a recent phase of ‘east-to-west’ extension along western Greenland,” according to Space.com.
The researchers said Davis Strait is one of the largest known clusters of rift structures with well-defined changes in plate motion that could help understand how microcontinents formed.
The beginning of the initial rift
According to the study, the initial rift between Canada and Greenland began about 118 million years ago, but the seafloor didn’t start spreading until 61 million years ago to form what is now Davis Strait.
About 3 million years later, the scientists reported, the seafloor spreading shifted from northeast to southwest, cutting off the small, straight Davis protocontinent.
The shift continued for about 33 million years and only stopped when Greenland collided with Ellesmere Island to the north.
The researchers hope their findings can be used to understand how other small protocontinents around the world formed, including the Jan Mayen microcontinent northeast of Iceland and the Golden Drake Knoll off the coast of Western Australia.
