Strange rock

I saw this chunk of rock on the slope and hadn't seen this variety before. I have no clue as to what kind of rock this is but I'm sure someone out there who sees this pic might know and help identify it. Thanks in advance.


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Marcsoltan - May 2, 2009 9:55 am - Voted 10/10


I don't know the first thing about geology, but I've seen a lot of volcanic rocks that looked just like this. Are there any volcanos nearby? Sometimes the chunks get blown for many miles.


Dean - May 2, 2009 10:11 am - Hasn't voted

Re: Dean

It looks like a big chunk of brown pumice but yet I had never seen anything like it. Mike also hadn't seen anything similar and I really don't know if there is volcanic remnants in the Silver Island range. I will be returning to the area to visit more peaks there and will try and ask my geologist son in law. Thanks Marc.


Klenke - May 2, 2009 1:46 pm - Hasn't voted

Re: Dean

It could be a remnant chunk of a reef. Wasn't there an inland sea in Utah at one point? It looks like reef rock but also pumice at the same time.


Dean - May 2, 2009 2:04 pm - Hasn't voted

Re: Dean

Hmmm, reef. Yes, the whole area was seabottom at one time. It was strange to find this all by itself, almost like an erratic from the Missoula Ice floods that hit
eastern washington.

listorama - May 2, 2009 6:46 pm - Hasn't voted


This very well could be detritus ejected from the bathroom of an Alien spacecraft that was flying here on a reconnaissance mission. Touching it would not be a good idea. I have already said too much.


jackstraw0083 - Jun 2, 2009 4:07 pm - Hasn't voted


Hard to tell from a pic, but it may be a weathered tuff (lithified volcanic ash). I know there's a lot of tuff out in that area.

Alex Wood

Alex Wood - Jan 27, 2010 10:48 pm - Voted 10/10

Pyroclastic debre

I am calling it volcanic because of its vesicular texture. Pumice can be carried (convected) pretty far in a plinian eruption and it can even float. So it has a long range. Probably some time rhyolitic pumice. Did you happen to pick it up?


Dean - Jan 30, 2010 9:31 am - Hasn't voted

Re: Pyroclastic debre

We did pick it up and it wasn't light like pumice would be. An interesting rock but most likely volcanic.

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