northspur

After the last ice age, the whole Lower Churchill Valley was
inundated by the sea up as far as Gull Island and a bit beyond.
Consequently, marine clays were laid down in these areas, after
which these clays were covered by more sediments as the land
uplifted. The general limit of glacio-marine clays in the North Spur/
Muskrat Falls area is at 130m above sea-level (Liverman (1997)).
Click
http://www.nr.gov.nl.ca/nr/mines/geoscience/publications/currentr
esearch/1997/liverman.pdf to see this document.
These “glacio-marine” clays have very peculiar properties that make
them infamous as a cause of massive rapid landslides (see red
triangles on next slide).
As the next slide shows, landslides (“failed slope”) are common along
the Lower Churchill Valley.
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