New microcontinent identified between Greenland and Canada is a crustal anomaly

New Delhi, India

Scientists have discovered a submerged microcontinent offshore of west Greenland. It has been named the Davis Strait proto-microcontinent since it formed owing to the tectonic evolution of the strait in the region. 

Continent formation is directly linked to plate tectonics which are also responsible for natural occurrences like earthquakes, volcanic eruptions and mountain formations. The movement of these plates, especially at their margins, results in the above natural events. A plate boundary lies between Canada and Greenland and forms the Davis Strait. The tectonic evolution of this strait is dated to ~33–61 million years ago (Ma) during the Paleogene and resulted in the formation of an unusual feature. Researchers say that there is a thicker-than-normal fragment of continental crust in the ocean owing to this evolution.

The microcontinent is 19–24 km thick thinned continental crust and is surrounded by two narrow bands of thin (15–17 km) continental crust. This crust separates it from mainland Greenland and Baffin Island.

How did the crust form?

Research published in Gondwana Research is working to understand how this crust came into being. For this, the researchers created a reconstruction of the plate tectonic movements spanning ~30 million years which have led to the creation of this proto-microcontinent.

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Doctoral researchers Luke Longley, Dr Jordan Phethean (University of Derby, UK) and Dr Christian Schiffer of Uppsala University, Sweden, define proto-microcontinents as "regions of relatively thick continental lithosphere separated from major continents by a zone of thinner continental lithosphere."

They studied the age of faults linked to the rifting, the mid-ocean ridge and associated transform faults by using maps derived from gravity and seismic reflection data. 

Researchers say that the initial rifting between Canada and Greenland began in ~118 Ma during the Lower Cretaceous. The seafloor started spreading in the Labrador Sea and Baffin Bay at ~61 Ma.

However, the formation of the proto-microcontinent was linked majorly to the period ~49–58 Ma. The orientation of seafloor spreading between Canada and Greenland altered from northeast-southwest along the Pre-Ungava Transform Margin, rifting off the Davis Strait proto-microcontinent. Greenland later collided with Ellesmere Island and joined the North American plate.