Maine's ~600 Million Years of Heritage
The geologic history of Maine involves the formation of mountain ranges (“orogeny”) and ocean basins (“rifting”) through plate tectonic collisions and separations. The Appalachian Mountains of eastern North America formed during ~600-200Ma of plate collisions and are still present in the modern landscape although greatly denuded after millions of years of erosion. The Atlantic Ocean, an iconic feature of coastal Maine, began opening about 200Ma with the breakup of Pangea, and is still widening today along the Mid-Atlantic Ridge.
A chain of super volcanoes formed along the eastern margin of the continent from subducting plate tectonics forming large plutons of intrusions granite rock. Mount Desert Island was once one of those volcanoes.
Over the last million years, the coast of Maine has been shaped by a series of continental glaciers that have carved valleys, deposited sediment, and changed sea levels.
After Maine was ice-free around 12,000 years ago, people started to settle in the region. Since then we have modified the landscape in many ways.