Tuesday, February 3, 2015

Circle 'Round the Sun in Water Canyon

Yesterday, when out hiking in nearby Water Canyon (before the Super Bowl), MOH and I slowly (at least for me) made our way up a variably steep, grassy to rocky hillside until we came to a large rib of quartzite. While standing there admiring the many geological and other features of the rib (including quartz veins, fractures and joints, bright greenish yellow lichen patches, and packrat middens), I noticed that a nice circle (22° halo) had formed around the sun. I moved into position behind the towering quartzite rib and shot a picture or two. The best one (which is enhanced to match the way it looked on the camera, which is the way it looked IRL except for the high contrast or excessive darkness of the foreground, where my eyes could see better than the camera) is shown above. You can also see just a bit of the bright greenish yellow lichen on the quartzite, barely shining through the camera-darkened foreground.
The lichen, also with a more common dark gray to black or dark brown variety and a pale green variety, can be seen better in this photo showing the same quartzite outcrop, although here I've moved over a little to the right to center the photo on a tall, narrow cleft formed along a couple parallel fractures or joints, possibly a small fault zone.
I immediately walked into the fracture so I could turn around and take this picture looking back to the north. The white bands in the center of the brownish quartzite, slanting shallowly to moderately to the right, are several of a complicated quartz vein set that are no doubt saying something about the stress regime during the time of their formation.

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