Similarity between Vermont Slate & Welsh Slate
FIG 1. Evolution of the Earth dueto Plate Textonics (Watson, 1.999)
The Slate Valley of Vermont is unique in the world because of its formational history.
Metamorphism of shale into slate and the different cooling temperatures acted to make many different
colors of slate in this very small area.
It is world renowned for this fact.
The slate in this region has been formed between 450 and 650 million years ago during the Cambrian
and Ordovician Periods of the Paleozoic Era. The reason why slate is so widely dispersed throughout the world
is due to plate tectonics. At one time, every continent on the earth was combined into one major landmass,
Because the continents were all joined together, there were shared areas of similar rock formation.
For example, the slate in Vermont and New York has similar formation times and characteristics to the slate
from Wales. Nowaday, the slate valley is a fairly large area that covers parts of two different states. It is
located in Rutland County, Vermont and Washington County, New York. Overall, it measures approximately
thirty miles from north to south and about ten miles from east to west, a total area of about 300 square miles.
FIG 1.1. PERMIAN 225 Million years ago.
FIG 1.2. TRIASSIC 200 Million years ago.
FIG 1.3. JURASSIC 135 Million years ago.
FIG 1.4. CRETACEOUS 65 Million years ago.
FIG 1.5. Pesent day.