[BR-Crater] for comparison: photos of shatter cones near Santa Fe, NM

[Ian Kluft]

Over the weekend I visited Santa Fe, New Mexico and got photos of
shatter cones in that area.  For those who were looking for more
photos of shatter cones to use for comparison in our search at
Black Rock, here are some dozens of new images to use.
   http://ian.kluft.com/pics/nm-200809/

The shatter cones were in a decades-old highway cut on New Mexico
State Route 475 in the Sangre de Cristo Mountains northeast of
Santa Fe, just outside the entrance of Hyde State Park ("one of the
oldest state parks in New Mexico"), which is also used in Winter to
access a ski area.  They went unnoticed until recently.

A geologist noticed the shatter cones in 2005 and published a paper
in 2007.  The shatter cones now on the surface at 8000' elevation would
have been below the crater floor or in a central uplift - except this
crater's suface features seem to be completely eroded away.
   http://www.lpi.usra.edu/meetings/lpsc2007/pdf/1207.pdf

In my visit to the area, I found that the shatter cones occur all along a
half-mile stretch of SR475.  In one area where there was a landslide onto
the side of the highway, all the rocks in the landslide contain shatter
cones. Then for a mile either side of that are fractured rocks which exhibit
some similarities to shatter cones, including apexes, crossing sets of
parallel fractures and joints, etc.

Over a matter of steps in the walk, the quality of the cone formations
varies with the changing types of rocks.  In some places they have the
nice textbook striations.  In others, you couldn't tell if they hadn't
been surrounded on both sides by better formations.

Those fracturing patterns outside of the area of well-formed shatter cones
are very similar to what we've been seeing over a much larger area at
Black Rock.

I brought back some small handheld-sized samples.  There were a lot of
already-broken rocks on the ground to choose from.  But I had to keep
these small since I brought them on carry-on luggage.