Presqu’ile Lake and its crater

Presqu'ile Lake and its crater

Presqu'ile Lake is located south of the town of Chapais, James Bay Region. It has a diameter of 24 kilometres.

This lake was studied during the decades by many scientists who discovered here unusual metamorphic rocks characteristic of a meteoritical formation. These zones are called “collision cones”.

These shatter cones are developed in massive, fine-grained rhyodacites. Thus, there is circumstantial evidence that about 500-800 million years ago (as no reliable date is available, the age is estimate on the high degree of erosion), a huge meteorite struck the earth’s surface at the place.

However, neither PDF in quartz or other minerals nor evidence of microbrecciation has been found at this supposed impact site. The crater with a diameter of about 7 kilometres has undergone up to 3,000 metres of vertical erosion, making it difficult to identify today.

Anyway, the circular shape of Presqu’ile Lake supports the hypothesis of a meteoritical collision.