THINGS TO SEE
As you look at the large rock near the side door in the Discovery Center’s inner courtyard, you’ll see many small impressions, the size of a dime or smaller. These are the remnants of raindrops from a summer day in the Jurassic period, 200 million years ago.
THINGS TO KNOW
A different climate. Back in the Jurassic, Turners Falls was near the equator, so the noon sun was directly overhead and very bright. Our climate was tropical to semi-tropical, and because this was a rifting or sinking valley, a shallow lake periodically flooded much of our area.
In fact, the whole Earth was warmer in the early Jurassic than it is now. As with the present-day climate of Costa Rica, summer rains were likely short but intense. The hot sun would quickly dry the fine muddy lakeshore, leaving large mud cracks like those we can still see today on mud flats in many regions of the world, from Utah to eastern Africa. Once in a while in those ancient days, afternoon showers would pummel the lakeshore and sometimes these showers left behind tiny raindrop impressions.
How did the raindrop impressions form? Because the warm sun would quickly dry the impressions to a solid or semi-solid state, they were not washed away when the lake water rose. Instead, when more rains would come, the lake waters brought more fine mud that buried the impressions a few fractions of an inch beneath the water surface. Like a photograph from the early Jurassic period 200 million years ago, the raindrop impressions in this rock record a moment in the history of the Earth.
NEXT STOP
Walk to the Rock Garden in the middle of the Discovery Center grounds.
