Plate tectonics determine the earth’s continental makeup, causing earthquakes, volcanic eruptions and mountain formations, and according to a recent study, the movement of these plates between Canada and Greenland has caused a microcontinent to emerge.
The plate boundary which exists between Canada and Greenland is responsible for forming the Davis Strait seaway, which connects two ocean basins, the Labrador Sea and Baffin Bay. According to Phys.org, the tectonic evolution of the Davis Strait can be dated to between 33 and 61 million years ago, during the Paleogene. During this period, an unusual geological phenomenon occurred – a thicker than usual section of continental crust in the ocean.
This anomaly is now considered to be a newly-accepted, submerged microcontinent offshore of west Greenland known as the Davis Strait proto-microcontinent.
New Research into the Greenland Microcontinent
New research published in the journal Gondwana Research seeks to better understand the mechanism and reason for this aberration in the crust formation on this particular plate boundary. Doctoral researcher Luke Longley and Dr. Jordan Phethean, along with Dr. Christian Schiffer, have produced a reconstruction of the plate tectonic movement going back roughly 30 million years that formed the microcontinent.
They categorize proto-microcontinents as “regions of relatively thick continental lithosphere separated from major continents by a zone of thinner continental lithosphere,” per Phys.org.
“The well-defined changes in plate motion that occur in the Labrador Sea and Baffin Bay, which have relatively limited external complications affecting them, make this area an ideal natural laboratory for studying microcontinent formation,” Dr Phethean told Phys.org.
Adding “Rifting and microcontinent formation are absolutely ongoing phenomena — with every earthquake we might be working towards the next microcontinent separation. The aim of our work is to understand their formation well enough to predict that very future evolution.”
With the aim of further understanding this, the researchers employed maps taken from gravity and seismic reflection data to ascertain the orientation and age of faults pertaining to rifting, the mid-ocean ridge – where Greenland rifted away from the North American plate – and connected transform faults.
The team determined that initial rifting occurred between Canada and Greenland around 118 million years ago during the Lower Cretaceous, with seafloor spreading beginning in the Labrador Sea and Baffin Bay at around 61 million years ago.
It was then noted that the period between 49 and 58 million years ago was key to the formation of the proto-microcontinent. In the model used, the Davis Strait proto-microcontinent is located based upon crustal thicknesses, where the microcontinent seems to be in the range of 19–24 km-thick.
Several islands in the eastern Indonesian Archipelago are considered continental fragments, or microcontinents, as well as other regions of the world. The archipelago is home to numerous microcontinents with complex geology and tectonics.