Friday, September 21, 2012


I'm still here!  OK so I've been insanely busy for the last few months with work and planning my wedding but now that I'm all married hopefully I can get back to posting.  I know...I say things...anyway, this time the post is about...GEOLOGY!

I'm not very good at geology so I invite you to berate me for inaccuracies in the comments.  The image above I made during my last trip to the White Mountains in New Hampshire.  This is a body of water called a tarn near Mt. Lafayette.  A tarn is essentially a mountain lake.  The basin of the lake is formed by a glacier and is always found on one side of a mountain slope.  You can see said slope above the tarn in this image.  

Often a terminal moraine provides a dam that keeps water in the basin.  What's a terminal moraine you ask? Well that's one bit of geology I actually am fairly confident I understand.  So when a glacier slides across the landscape (glaciers are so huge, by the way and I've never actually seen one in real life...I have to imagine an ice sheet of this size) it picks up a lot detritus including rocks and boulders.  Here in New England if you've ever spied a huge boulder just sitting all by its lonesome in a field with no other boulders around you can be pretty sure a glacier dropped it there.  So anyway, the glacier will pick up rocks and boulders and also drop them.  A moraine is a collection of detritus, soil, rocks, boulders, etc., dropped by a glacier.  A terminal moraine is a moraine formed at the furthest advancing edge of the glacier.  Usually the largest accumulation of debris is at the "snout" of the glacier (the advancing face/edge) and as the glacier finally stops and begins to melt it leaves a (sometimes) massive pile of rocks and such.  

So it's this kind of moraine that provides the dam for a tarn.  Now you can impress your friends by telling them about tarns and moraines.  Fun geology words!

OK I have a few other photos from the Whites I'm hoping to post.  Get ready for FUNGUS!

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