Rock identification?

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Rock identification?

Postby gindling » Jun 25, 2013 9:51 am

So I'm bolt climbing in this Ordovician Dolomite cave and I come across this red to yellow, light and slightly chalky feeling deposit on the otherwise black dolomite and im trying to figure out what it is and how it fits into the speleogenesis of the cave. Any help would be greatly appreciated.
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Re: Rock identification?

Postby Phil Winkler » Jun 25, 2013 12:17 pm

An iron oxide deposit? I think sulfuric acid on a sample will create a black iron sulfide.
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Re: Rock identification?

Postby gindling » Jun 25, 2013 7:17 pm

I'll do that.Thanks for the idea.
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Re: Rock identification?

Postby Squirrel Girl » Jun 26, 2013 5:14 am

Typically, yellow/orange/red things are iron oxyhydroxides. The yellow/orangy things are limonite and red is hematite. That's probably what these are, though many things people think are iron staining are really organics in flowstone.
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Re: Rock identification?

Postby Phil Winkler » Jun 26, 2013 8:16 am

Thanks, Barbara, for the info. In an earlier life I wanted to be a geologist and attend the Colorado School of Mines. Instead, I got drafted and became a caver. :)
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Re: Rock identification?

Postby gindling » Jun 26, 2013 9:35 am

This cave has a large fault running on the north side of an uplifted block of limestone with a very active hot spring at the fault zone making me believe that this is a hydrothermal hypogene cave. Hematite and Limonite are both known markers for hypogene caves (as well as nailhead spar, roof pendants, ceiling cupolas) so i'm getting a better understanding as to how this cave formed and where I should be bolting to so I can find all those miles of passage I dream is there... Thanks to you both. I had an inkling thats what they were and I was hoping for some reassurance.

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