Sunday, January 24, 2010

Written in Stone - New England Geology

After Ed Myskowski piqued my interest in the geology of New England, I borrowed "Written in Stone" by Chet and Maureen Raymo from the Arlington Robbins Library. A great introduction to the geology of New England. Plate tectonics is central to the discussion. It has changed my whole conception of time, and how mountains, lakes, rivers and valleys formed.

I had heard about "Pangea" the super-continent, but hadn't heard about how the continents were arranged before they coalesced to form Pangea. As impressive as our mountains are now, this book describes how before Pangea a mountain range rivaling the Himalayans stood along what is now the East Coast of North America. At the time though, this land was located near the equator.

The continents have joined and separated, plant and animal species have come and gone, rocks have formed, compressed and changed, mountains have been thrust up and have eroded to plains. In geologically recent times, the land has been shaped and tilled by glaciers. In the last few moments of geologic time, a creature with an unusually large brain has walked the earth. The longevity of this species is to be determined, over the next few 100 millions of years.

For a great animation of the tectonic movements of the earth's land masses, leading to our current continents, see this Animation from UC Berkeley . Note that you can step through the sequence slowly with the left/right arrow keys. Watch Florida float into place at about 430-270 (million years ago) and India zoom up and slam into Asia starting about 120 million years ago.

Added on 6 Mar 2010: A video dramatization and Plate Tectonics primer: