Friday, August 29, 2008

Gros Morne Tablelands

In Gros Morne National Park in Newfoundland, one can see a geological rarity, the Gros Morne Tablelands. Here an ophiolite sequence is exposed. This is a slab of ocean floor that has been jammed up onto the North American continent. These rocks are normally found between the floor of the ocean and the earth's mantle which underlays the crust typically about 3 miles beneath the ocean floor.


These rocks can be seen be seen by taking a boat tour on a lake called the Trout River Pond. (Newfoundlanders call virtually all of their lakes "ponds")




Because of the chemical composition, few plants will grow on the rocks of the Tablelands.








These are "pillow basalts" that form underwater when magma oozes up onto the sea floor at a tectonic "spreading center" where new sea floor is being created.



These rocks are from the Mohorovičić discontinuity (commonly called the "Moho"). This is the area where the bottom of the Earth's crust rests on the underlying mantle .

This area is definite "must see" for anyone with an interest in geology.

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