[Stratofox Announce] photos from Crater Assault 2

[Ian Kluft]

The Stanford BioLaunch B07C balloon flight was delayed a week to June 9.
So four of us went to Black Rock this past weekend for "Crater Assault 2".

Pictures are at
   http://www.stratofox.org/pics/sca2-20070602/

The attendees were Jim Dennis KG6ZXF, Brad Douglas KB8UYR, Ian Kluft KO6YQ
and Heather Stern KG6ZYC.

Looking into the theory of an impact crater at Black Rock is consistent
with Stratofox's efforts at familiarization with Black Rock.  But it isn't
of interest to all who came to Stratofox looking for rockets and balloons.
So we created the br-crater mail list for that topic.  After this overview,
please direct follow-up discussion there.  You can subscribe yourself at
   http://www.thunder.net/mailman/listinfo/br-crater

We achieved one of the two orignial goals of the trip.  We visited another
circular shaped valley near Black Rock which we've been eyeing on the maps
since January.  We couldn't find an official name for it.  Based on a
geology paper's description of it as a "donut-shaped" basin, we nicknamed
it "Donut Basin".  There's a hill at the center of it which we nicknamed
"Donut Hole Hill".  Donut Basin is located at 41.164069 N 119.568155 W
and is about 12 miles in diameter.  Washoe County's unpaved Hwy 34 goes
through it.  It's at the upstream end of Little High Rock Canyon.

Part of the interest in this site, besides the circular shape, is that
a 1970's geology paper described it as a "failed caldera".  Since then
others have cited that paper - but no one seems to have revisited the
claim as far as we can tell.  There are no other examples of any "failed
caldera".  A volcanic caldera doesn't fail to finish collapsing once it
starts.  So we wanted to look at it for evidence of a second possible
impact crater in the area.

We climbed to the top of Donut Hole Hill, which is in the right place to
be a central uplift in an impact crater.  We didn't see any proof of an
impact.  But we found ocean-bottom sedimentary rocks near the top of the
hill, which practically rules out a volcanic origin on its own.  There are
lava rocks above the sedimentary layer, which could be impact melt and are
in the right place for it on top of the central uplift.  All over the
basin the rocks are similar to the Black Rock region where we already
have evidence of a possible impact.

So that was more than enough to get us interested in Donut Basin as a
potential impact crater.  But interest is all we really have so far.
Brad will look at multispectral satellite imagery for chemical composition
of the rocks across the area.

We wanted to go next to Upper High Dry lakebed in the Black Rock Range.
That's near the center of the possible 40-mile impact crater at Black Rock.

But several things made us give up on that.  We had a late start at
Donut Basin and got out at dark.  We were all exhausted.  One member
of our group became ill.  As if that wasn't enough, one of the scattered
thunderstorms that evening was in progress over the southern Black Rock
Range when we would have been trying to go there, raising the risk of
encountering mud in the dark.  Upper High Dry will have to wait.