Under the Sea
During the Protoerozoic Eon, the
proto North American continent did not include what today is known as
New England or the Canadian Maritime Provinces. Much of the land
that would one
day create these states and provinces either lay at the bottom of the
oceans
or were attached to other continents at this time!
The Green Mountains of Vermont
were created in the Grenville Orogeny. An orogeny is what
geologists call a mountain building event due to the collision of land
masses. The rocks that became the Green Mountains were sedimentary
rocks. These particular rocks were created from sea sediments,
mostly shale (compacted muds) and limestone (the collection of
skeletons of tiny sea creatures and carbonates that settled out of the
ocean), off the coast of the early North American continent.
These sediments were uplifted under great pressure and
temperature as a result of the land masses pushing against each other.
This great pressure and heat changed the physical nature of the
shale into slate and the limestone into marble. When the
physical
characteristics of a rock are changed due to intense pressure and /or
heat,
geologists call the new creation metamorphic rock.
This is important for New
Hampshire because most of the Granite State is not granite - which is an igneous rock created from the solidification of magma (molten rock). Most of the bedrock in New Hampshire is actually metamorphic rock!
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Vermont
Ocean Beachfront? |
This image from the coast of
New Hampshire shows the Atlantic Ocean as it is today. After the
Grenville Orogeny created the Green Mountains, by lifting up ocean
sediments, this could have been what the coast of Vermont looked like!
(Click
on the image for a closer look.)
Image Credit: Daniel
E. Reidy
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