Grand Caverns, Grottoes, VA

And that's a title only cavers can understand fully.  First up, Grand Caverns is a commercial cave located in Grottoes, VA.  Take a tour if you are in the area (just south of Harrisonburg, VA) as it is a pretty and historical cave.  Discovered in 1804, it is the oldest continuously operating show cave in the US.  Tours started there in 1806.  They have a pretty nice website at:  http://www.grandcaverns.com/v.php?pg=15

Next up, the name.  Grand Caverns was adopted in 1926, presumably to shorten the cave name and give it a name appealing to tourists.

And finally, the name of the town.  I don't know the history, but can explain the word "grotto."  A grotto is a cave with human usage in some way, and Grand Caverns has seen human usage as a show cave and historical site for over 200 years.

I was there as part of a group that has volunteered over the last many years to map the cave, clean the cave, improve the cave and generally use caver volunteers to help out as needed.  Many, many projects have been completed.  But one project that needs continual attention, is the cleaning of green stuff growing around the lights that are used for the commercial tours.  Yes, as said so eloquently in Jurassic Park, "Life will find a way," and here it is algae and such that grows underground, and is green with chlorophyll, using the cave's lighting as an energy source.  Such things are not part of the normal cave ecosystem, so need removed.

And of course, while in the cave, I took my usual bunch of photos, and will put them up here over the next couple days.  For today, I am going to focus on soda straws, because I posted the quite interesting soda straw with an air bubble recently from Melrose Caverns, and figured to post some pics of normal soda straws in action.

But first...

I arrived Friday night (with my son along) and it was on the cold side, dropping to 27 degrees. So we had a fire in the outdoor pavilion where we were camping. Note this is NOT a campground, the cavers have special permission to do this to be more effective.

And waking up in the morning I crawled out of my tent, which I set up under the pavilion on one very hard and cold cement slab, I saw...

Lots of sunshine, which was great, and still lots of snow on the ground.

But I was here, with some old friends and my kid, and time to look around.

A sign in the woods. Welcome! So much better than all the No Trespassing signs these days

The property is a community park located on the South River, and this is looking downstream

And this is looking upstream. A fine trail goes along the river and a few folks were fishing for trout

Looking across the park toward Cave Hill, where the entrance to Grand Caverns is about halfway up

But that's enough about the site, let's talk about soda straws.  These are cave formations made out of calcium carbonate that form when a drop of water is released from the cave ceiling over and over again for many years from the same spot.  They are, as one might suspect, hollow tubes roughly the size of the straw you drank your last McDonald's soft drink with. 

The water comes through the limestone rock, and drips from the ceiling of the cave.  And each time it does this the water de-gasses a bit of carbon dioxide and deposits a bit of calcium carbonate around the circumference of the drip, forming a tube with a drip at the bottom, and the water coming through the tube.

So it is a crystalline structure, made of calcium carbonate (with a few other possible chemical compositions that do not need mentioned here), that is in the shape of a soda straw and has water moving down the middle of it. 

And a brand new one looks like this...

Very young soda straw, only just starting to get the form. Probably less than 200 years old, but really shows the crystal growth around the rim.

And getting back to the issue of things going green underground, here is a green soda straw.  We were not tasked to clean formations, just clean the crud from around the lights, but this demonstrates the trouble that commercial caves have in keeping down the green stuff.

Green soda straw due to commercial lighting. Cool pic, but not what you want your soda straws to look like.

Now the proper soda straw shots, after so much ado...

A small soda straw (with another in the background) just starting to load up some water from it's ceiling source. At this point it is weighted to the left

Now the little straw has a proper water droplet.

And then off it goes, leaving a tiny bit of calcite to continue the soda straw, and maybe a tiny bit to continue the stalagmite below

And a crop of this one for folks who want to see the nitty gritty details.

Right after a drop falls from a soda straw

And that's the story on soda straws.  More tomorrow from the Grand Caverns weekend.