Tuesday, November 13, 2012

Scratching the surface

The cliffs of Bell Island at some 200 feet high are quite imposing when looking up from the seat of a kayak.  But what is exposed at sea level is only scratching the surface.

These rocks were laid down in an Ordovician sea between 485 and 443 million years ago on the micro-continent of Avalonia which had separated from the super continent of Gondwana, in what was then a southern ocean.  Since then its drifted a long way north.

Fourty-two million years is a long time and a lot of sediment can build up over that time.  E. R. Rose estimates this series of rocks have a measured thickness of more than 8,000 feet in a Geological Survey of Canada memoir from 1952.  There's obviously way more to this "book" than what is to be seen at sea level.

No comments:

Post a Comment