HomeOpinionNew microcontinent discovered between Greenland and Canada

New microcontinent discovered between Greenland and Canada

Plate tectonics is the driving force behind the continental configurations of the Earth; the lithosphere (oceanic and continental crust and upper mantle) moves due to convection processes occurring in the softer asthenospheric mantle below. Many earthquakes, volcanic eruptions, and mountain building are direct results of the movement of these plates covering the Earth, especially at their edges.

One such plate boundary runs between Canada and Greenland, forming the Davis Strait, which connects two ocean basins, the Labrador Sea and Baffin Bay. The tectonic evolution of the Davis Strait dates back to approximately 33–61 million years ago (Ma) during the Paleogene, during which time a particularly unusual feature formed: a thicker than usual (19–24 km) section of continental crust in the ocean.

It is now recognized as a newly recognized, incompletely submerged microcontinent off the coast of West Greenland: the Davis Strait protomicrocontinent.

Understanding the mechanism and cause of this crustal anomaly is the subject of a newly published study. Gondwana ResearchDr Luke Longley and Dr Jordan Fetean (University of Derby, UK), together with Dr Christian Schiffer (Uppsala University, Sweden), have produced a reconstruction of the plate tectonic movements over approximately 30 million years that led to the formation of the proto-microcontinent. They define protomicrocontinents as “areas of relatively thick continental lithosphere separated from the main continents by a region of thinner continental lithosphere”.

Dr. Fetean explains why this particular location was so important to this study and why studying the past formation of microcontinents is vital for today. “The well-defined changes in plate motion that occur in the Labrador Sea and Baffin Bay with relatively limited external perturbations making this area an ideal natural laboratory for studying the formation of microcontinents.

“The formation of rifts and microcontinents is definitely a permanent phenomenon. With each earthquake we can study the next separation of microcontinents. The goal of our work is to understand their formation well enough to be able to predict the same evolution in the future.”

New microcontinent discovered between Greenland and Canada that is not completely split
A model of plate tectonic evolution between Canada and Greenland that defines the location of the Davis Strait Protomicrocontinent (DSPM) and also shows the location of transform faults along the Mid-Atlantic Mid-Ocean Ridge and the thickness of the continental crust. Authorship: Longley et al. 2024.

To investigate this in more detail, the research team used maps derived from gravity and seismic reflection data to determine the orientation and age of faults associated with rifting, the mid-ocean ridge (where Greenland separates from the North American plate) and associated transform faults (where two tectonic plates slide past each other).

Scientists have determined that the first rift between Canada and Greenland began about 118 million years ago during the Lower Cretaceous period, and that seafloor spreading in the Labrador Sea and Baffin Bay began about 61 million years ago.

Later, the period ~49–58 Ma is considered key to the formation of this proto-microcontinent, with the seafloor spreading between Canada and Greenland changing orientation from northeast to southwest along the north-south boundary before the Dungava transform, breaking away from the proto-microcontinent at the Davis line. Oceanic spreading ended approximately 33 Ma, with the collision of Greenland with Ellesmere Island and the subsequent accretion of Greenland to the North American Plate.

In this model, the Davis Strait proto-microcontinent is defined by crustal thickness; here the microcontinent appears as a 19–24 km thick range of thin continental crust, surrounded by two narrow thin (15–17 km) bands of continental crust that separate it from mainland Greenland and Baffin Island.

This research can be applied to other microcontinents around the world to understand how they break away from the continental crust, including the Jan Mayen microcontinent off the northeast of Iceland, the East Tasman Rise off the southeast of Tasmania, and the Gulden Drake Hills off the coast of Western Australia.

“A better understanding of how these microcontinents form allows researchers to understand how plate tectonics work on Earth, which has useful implications for reducing plate tectonic hazards and discovering new resources,” Dr. Fetean says.

Source: Port Altele

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