A new microcontinent has been discovered in Davis Strait, between southeastern Canada’s Baffin Island and southwestern Greenland.
In a new study, researchers from the UK and Sweden mapped the microcontinent using gravity data and seismic reflection data to create a tectonic reconstruction of the region.
Although the geology of the region has been extensively studied previously, some mysteries remain.
How did a new microcontinent form in the Davis Strait?
“A prolonged period of seafloor rifting and spreading between Greenland and North America formed the Labrador Sea and Baffin Bay ocean basins, connected by Davis Strait,” the team explains in the paper.
“However, there is disagreement about the exact movements of the plates between Greenland and Canada, as well as about the tectonic evolution of Davis Strait, with previous models unable to explain the origin of the abnormally thick continental crust within the water,” the experts say.
While reconstructing the area’s past as Greenland separated from Canada, the team discovered that the abnormally thick crust is actually a new microcontinent, a tectonic block that has broken away from a continent and is surrounded by thinner oceanic crust.
“Reinterpretation of seismic reflection data from the west coast of Greenland, together with a newly compiled model of crustal thickness, identifies an isolated terrane of relatively thick (19–24 km) continental crust that was separated from Greenland during a new recognized phases of EV extension along the western margin of Greenland. We interpret this continental block as an incompletely broken microcontinent, which we call the Davis Strait proto-microcontinent,” the team wrote.
How old is this microcontinent?
Researchers believe that rifting (where the tectonic plates split in two) began about 118 million years ago, before continental separation occurred about 61.27 million years ago in the Labrador Sea. The continents continued to drift, before Greenland collided and joined the North American plate. During this period the new microcontinent was created, writes IFL Science.
“As our seismic reflection interpretations indicate an extensional event east of Davis Strait between 58 and 49 million years ago that is spatially coincident with the thinnest continental crust zone between the continental shelf and Greenland, we infer that this event of extension led to the separation of this fragment from Greenland”, say the researchers.
The team hopes that the research could help to better understand plate tectonics and the risks they can cause to Earth’s inhabitants.
“Overall, this work not only recognizes several new first-order tectonic features of the Earth, the Pre-UTM proto-microcontinent and the Davis Strait, but also indicates a strong control of the lithosphere on plate motion directions,” the team concludes.
“It is therefore fundamentally important to study this phenomenon in order to understand the functioning of tectonic plates on our planet,” the scientists conclude.
The study is published in Gondwana Research.
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Source: www.descopera.ro
