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Climbing and ... Climbing => Masters of Mud -- Pinnacles => Topic started by: mungeclimber on July 31, 2012, 01:27:21 PM

Title: green volcanic glass?
Post by: mungeclimber on July 31, 2012, 01:27:21 PM

This has been mentioned as being at Pinnacles, but I'm not sure what it is referring to.

Anyone seen this before?

Title: Re: green volcanic glass?
Post by: JC w KC redux on July 31, 2012, 01:53:30 PM

I've got an old field guide around here somewhere that gives some pretty good geologic background on the Monument.
I believe the rock you are referring to is called Perlite and it is green and glassy.
If I remember correctly we used to walk up Condor Gulch to a sizeable outcrop when we did a geologic mapping exercise with our West Valley classes. I'll email my colleague over there and get him to email me the guide.

Title: Re: green volcanic glass?
Post by: JC w KC redux on July 31, 2012, 03:05:24 PM

I found it and I was right - at least partially.
The perlite is a hydrated volcanic glass that can be green when fresh and weathers to grayish hues.
There is also a lapilli tuff that's green.
I'll scan some stuff and send you a PM probably tomorrow...
I've got a map that shows where the different rock types are exposed - it's pretty cool.

Title: Re: green volcanic glass?
Post by: mungeclimber on July 31, 2012, 03:17:05 PM

sweet, thx!!