Tuesday, July 24, 2012

New EarthCache Developed: Hill City Fold, Black Hills, SD

I've mentioned a couple of times previously that I spent the month of June out in the Black Hills of South Dakota, teaching field camp for Wheaton College at their Science Station.  It was a great experience and hopefully I'll get to give it a go again in the future.  I've also written recently about EarthCaches, a program between the Geological Society of America and  While in the Black Hills, I logged a number of EarthCaches and also recorded information about a couple of places in order to place some new ones.

The first one I've set up is a roadcut on Highway 16/385 near Hill City, SD, within the Black Hills.  The roadcut exposes a fantastic example of a fold.  EarthCaches must have an educational component, and for this one I ask the geocacher to identify whether the fold is a syncline, anticline, inclined, or recumbent, so the geocacher has to learn something about the axial plane of a fold and be able to recognize it in the rocks.  So, forgive me if I don't post a picture of it!  The cache description contains enough information for geocachers to know what these terms mean, so by observing the fold in the field this ought to be easy to answer this question.

I also ask the cacher to measure the horizontal length of the fold as exposed in the roadcut.  One of the easiest ways to measure distance over land is with a GPS, which every cacher ought to have with them in the field.  In order to navigate toward a point of interest, geocachers often enter the coordinates of a location into their GPS to set a waypoint, tell the GPS to "GoTo" the point, and the GPS will then tell them how far away the point is.  This obviously makes it easy to see your distance to the point decreasing as you get closer.  I have cachers use this technology in reverse - establish a waypoint (POI) at one end of the roadcut, tell the GPS to "GoTo" that point, and then they themselves physically walk away from it to the other end of the roadcut.  When they reach the other end of the roadcut, the GPS will tell them how far they've gone.  This exercise hopefully helps cachers to learn to use GPS technology in a way they might not have thought of before.  After all, why would I tell the GPS to "GoTo" a point, but then I myself "GoAway" from it?  It isn't an intuitive use of a GPS but works really well.

The new EarthCache was just approved, so we'll see how long it takes someone to visit the site and log it.