I was walking in the woods today near my house and I came across a recently uprooted tree. It fell over, probably in a storm that came through a couple months ago. A large circular area of earth around its base was peeled up and standing upright, held together by the roots. I looked into the gaping hole left in the ground and noticed a fairly big rock – about a foot in diameter. It had been buried under this tree, a good 3-4 feet underground. To my surprise, it was smooth and nearly round.
This got me thinking about how old that rock must be to not have seen the light of day in who knows how long and yet be smooth as if it had been sitting on the beach. A bit of Googling on New England field stones turned up a fact-filled page pointing to most of them being granite and deposited and worn down by glacial activity. And a bit more Googling on glacial activity in New England explains that, contrary to popular belief, there wasn’t just a single ice age 100,00 years ago, but dozens of them over the past million or so years, and hundreds upon hundreds before that. So who knows how many ice ages it took to make this hunk of granite round like a semi-flat basketball and deposit here, under this tree (which by my estimate was probably only about 80 years old) in some woods at the top of an esker (indicating the land probably hadn’t been cleared and tilled of rocks for farming).
Though it’s hard to find it pinned down precisely, multiple sources indicate that the granite in New England is probably hundreds of millions, if not billions of years old. That means this rock cooled from magma hundreds of millions of years before humanity existed. And there it is, just hanging out in the dirt, entirely unremarkable.
Our little sub-100 year lives are such amazingly teensy blips upon the surface of this great 4.5 billion year old planet, which is really just a spec of dust in the universe.
