Delaware Bay - Part I

            Imagine an annual celebration at your house – a special end-of-the-year holiday fête or a grand summertime reunion.  Scores of relatives and neighbors and friends – some from distant parts of the country - descend on your home to eat and drink and laugh and generally make merry.  For most of the day you feel like the ringmaster of a traveling circus trying to keep everyone hydrated and fed and entertained over the course of several very hectic hours.  Sometime during the festivities you and your spouse step outside for a “breather.”  You look at each other and with a heavy sigh pose the inevitable question, “How did this get to be so crazy?” 

Interestingly, that’s a question scientists have been asking about Delaware Bay - the largest spawning area in the world for horseshoe crabs. 

For now, let's imagine a mouth-watering, taste-tempting, genuine home-made cherry pie.  Think about that oh-so-sweet pie as it’s baking in the oven.  Smells are wafting through the kitchen, down long hallways, and out into the garden.  The pie is gradually and gently turning a rich golden brown; and after about 30-40 minutes a small rift – a crack – begins to appear in the crust.  Over the course of the next ten minutes or so the rift grows a little longer and just a little wider.  Soon, a lava-like glob of rich-red cherry filling bubbles out of the crack, cascades over the fluted edge, and onto the bottom of the oven.  Minute by minute additional blobs of cherry “lava” bubble up like thickened primordial ooze.  By the time the pie is ready to be pulled from the oven the crack has grown wider, longer, and most definitely “oozier.”

The scenario above is one I share with students in my science courses – particularly when we begin our discussions on plate tectonics, volcanism, and the early history of the earth.  Its imagery is immediate and sensory.  Most importantly, it is a  memorable (and most delicious) way to begin our journey into the past.

I tell students that the earth is not a static entity – it is constantly in motion; it is forever sliding, shifting, moving.  Tectonic plates continuously grind their way over and under each other, earthquakes rip through the earth’s crust with daily regularity,« volcanoes belch molten lava from subterranean bowels (just like our cherry pie), and wind and waves sandpaper the fragile surface time and time again.  The earth changes – it is never exactly the same from one day to the next, and certainly not from one eon to the next.

It is constantly evolving.

Our story continues in Part II - the next blog.

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« The US Geological Survey estimates that several million earthquakes occur in the world each year. Many go undetected because they hit remote areas or have very small magnitudes. The National Earthquake Information Center now locates about fifty earthquakes each day, or about 20,000 a year.