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 Geocaching.com.  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.

A Growing Collection of Geology Field Photos

Today over at Georneys, Evelyn suggested, in what's sure to become a geoblogmeme, posting geology pictures.  I love it when geologists share their photographs, and since late August I've started building my collection of geology photos and posting them on Google+.  It all got started when I decided to take a leap and submit one of my photos to the NASA site Earth Science Picture of the Day, and they accepted it.  I mainly did that because I was a bit bored of all the cloud formations that tend to dominate the EPoDs (need more geologists submitting their pics to this site!).  Anyway, that experience as well as the huge amount of great photo sharing on G+ led me down this path.

Isoclinal folds in high-grade gneiss, eastern Blue Ridge, Southern Appalachians.

The pics are being collected in an PicasaWeb album.  When I post them on G+, I give a longer description & explanation so my followers can learn something cool about geoscience.  All of the photos are geotagged and their locations can be seen on the map in the PicasaWeb album (unfortunately, the same album viewed in G+ does not have the spiffy googlemaps with it), so that others can visit these locations and see for themselves.

Chilled margin in granite, St. Francois Mtns., MO

I've cross-posted the links to the G+ posts on my BookFace & Twitter accounts, but so far the blog here hasn't seen them.  I've also tagged each of these posts with the hashtag #geopic.  In this way, anyone can see the photos and search for the descriptions I wrote about them easily on G+.  I'm happy to let any geoscience instructors use them (unaltered, of course) as examples in their lecture slides.  A lot of photographers post beautiful pictures of landscapes, and I'm not a serious photographer in that way; these are meant for science, not necessarily for art.

Deformed mudcracks, Valley & Ridge Province, east TN.

So without further ado, here's the link to the collection:

https://picasaweb.google.com/106934864033790932269/GeologyFieldPhotos

The collection so far includes 14 pictures (I post about 1 per week).  I also upload the photos to my panoramio account so they can be viewed in Google Earth & Maps.  The collection so far includes about 10 structures (3 folds, a textbook delta clast, deformed mudcracks, en echelon veins, liesegang rings, a chilled margin in granite, and GIANT-size joints & cross beds), 2 landforms, 1 fossil, and 1 mineral/crystal.  I guess that's a bit skewed toward the structures!

Delta clast in gneiss, Parry Sound Shear Zone, Ontario, CA.