In this geographical reconstruction of North America, you can admire Hudson Bay with Nastapoka’s Arch (in the southeastern part). 
Lorenzo Pasqualini meteorized Italy June 10, 2023 1:00 p.m. 4 min
When you look at a geographic atlas or surf the Internet on one of the many global satellites available, You might come across many curiosities of earth geography. One of them is in Canada, in the eastern part of Hudson Bay. Here, north of Blades Bay, A huge circular structure can be recognized by the characteristic “finger” that extends south from the bay.
A perfectly circular arch that cannot escape the attention of an attentive viewer. What is actually surprising it is its almost perfectly circular shape, whereas, as is often the case, one would expect a rugged coastline.
We stand in front of the Nastapoka arch, and the mystery surrounding the cause of this circular shape has motivated numerous studies and expeditions.
Many hypotheses have circulated about the formation of the mysterious Nastapoka Arch in Hudson Bay (Northeast Canada), and there has been lively debate about its geological origin.
A giant asteroid?
One of the hypotheses mentioned in the past is that of an asteroid impact. Also in Canada, a few thousand kilometers east of Nastapoka’s Arch, is the “Eye of Quebec”, Lake Manicouagan, a large freshwater basin with a diameter of approximately 70 km, with a very characteristic ring shape created by the impact of a huge meteorite.
However, the first thing you notice when comparing dimensions between Nastapoka Arch and Lake Manicouagan is the size. Lake Canada is about 70 km in diameter, while the Nastapoka Arch, if completed with a compass, would be 450 km in diameter.
So we would be faced with a meteorite of unimaginable proportions. However, no possibility is ruled out and geologists have been trying to figure out if this particular structure is involved for decades is actually the result of an apocalyptic meteor impact, but they found no evidence.
Image from NASA Earth Observatory, by Lauren Dauphin.
A geological field study conducted in the 1970s no evidence of impacts such as molten rock, radial fractures, etc.
The asteroid hypothesis is therefore currently on hold, Although some scientists have speculated that traces of an asteroid impact may have been erased by geological processes, and new hypotheses are explored.
The result of an ancient continental collision?
Today, Geologists generally believe that the arc is the result of a continental collision. According to a NASA article, it was a 2 billion year old episode of mountain building This so-called Trans-Hudson orogeny is said to have led to the first formation of the North American continent.
According to this theory, the Nastapoka Arch would be the remaining remnant to this day an arcuate tectonic plate boundary and would therefore have a tectonic origin.
Based on numerical modeling studies, regional geological studies and in the absence of evidence of an impact by an extraterrestrial body, There is currently general consensus on this theory of tectonic origin.