Wednesday, July 29, 2015

July club field trip

Samples of coral,  limestone showing mineral alteration and a volcanic rock with alteration halo and calcite crystals
Submitted by Anita Williams

The Rolling Stones July field trip was relatively close to home and we had a very nice crowd participating including some young pebble pups.  It was nice to have kids along on the trip having fun collecting rocks.  As one of our sage members observed during the trip the kids have a distinct advantage in rock collecting since they are closer to the ground.  There is definitely something to that along with keen eyes and abundant enthusiasm.
Field Trip Participants

Saturday hosted a clear blue New Mexico sky as we all gathered at Walmart at 8 am.  Right on schedule the car-a-van lined up and headed east for the Georgetown area.  Our collecting locales were in the Devonian/Mississippian limestones.

It was a short ride over to our first stop just off the Georgetown Road.  We searched the area for  limestone garden rocks.  In this spot there were some outcrops of lovely, weathered limestone blocks, but many were too big to handle on this trip.  Next stop was similar except the hillside also hosted some beautiful cacti some of which George collected for his cacti garden.  The limestones in this area were fossiliferous too.

Samples from the Prospect pit--the top rock is gossan on limestone, dendrites on clay and examples of bands of alteration
Silicified corals
Next stop was very near “old” Georgetown.  We parked on some more recent tailings and started scouring the hillsides for corals and other fossils.  I was investigating a prospect pit and finding some gossan (translation from German is iron hat).  It is usually an iron mineral such as hematite and it is an indication of mineralization in the close proximity—thus the prospect pit.  I also found some silicified volcanic rocks with calcite crystals and some dendrites on clay partings.  Meantime I started hearing excited chatter and the sound of rocks falling into plastic buckets and I headed over that direction.  Folks were collecting some beautiful specimens of silicified corals in that area.  Everyone found nice samples and toted their buckets back up the hill to the vehicles for a brief lunch break.

Our last official stop was near the old Georgetown townsite.  Down in the stream valley folks were finding some brachiopods and crinoids.  I was farther up the hill and found lots of old glass and square nails.  Ansel went off to check on another collecting area, but the day was hot and everyone was tiring.  Everyone opted out and headed back to town to look over their new found treasures.

Field Trip Participants

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