Tuesday, September 22, 2009

Mystery Photo of the...Day, Week, Month?

I haven't posted any mystery photos for a long time, but here is an intriguing pattern I caught yesterday. I know how y'all hate a lack of context, so here it is: I was at Bumpass Hell in Lassen Volcanic National Park.

So, what is going on here, and what materials are involved?

I have posted a video of this on Facebook, and I think you can access it here without having to sign up with Facebook:
http://www.facebook.com/home.php?ref=logo#/video/video.php?v=168206768711

POSTSCRIPT (9/26): This is a boiling mud pot. The magma providing the heat is at a depth of three miles or so, and groundwater seeping into the crust is heated to beyond boiling, and a vast steam reservoir has developed beneath Bumpass Hell. The steam condenses to hot water near the surface, but is charged with hydrosulferic acid, which does a serious number on the andesite lavas underlying the area. The rock is turned to clay, which forms the gray stuff in the mudpool. The black swirls are actually finely divided iron sulfide, the mineral pyrite. That's right, fool's gold! If you have had a basic class in geology, you may remember that pyrite is black in powder form (the streak). The patterns are hypnotic to watch.
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7 comments:

  1. Ron SchottSeptember 22, 2009 at 6:28 PM

    My best educated guess would be that the Stay-Puft Marshmallow Man was enjoying a dip in the hot springs when a tornado passed through.

    Surely there can be no other explanation!

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  2. LockwoodSeptember 22, 2009 at 6:52 PM

    I'm guessing the material on the surface is native sulfur precipitating out of (up from?) H2S-saturated water. I think I've seen that also at one of the Yellowstone boiling pools. It's being swirled into the cool patterns by turbulent flow in the pool.

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  3. Silver FoxSeptember 26, 2009 at 9:43 AM

    Darn! That's what I was going to guess - FeS2 for the dark swirls. But I thought Lockwood was on to something, and couldn't figure out what the light stuff was. Mud!

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  4. LockwoodSeptember 26, 2009 at 9:46 AM

    I had it completely backwards... I thought the lighter material was floating on darker water. Perceptions can be stupid things, to paraphrase Reagan.

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  5. Silver FoxSeptember 28, 2009 at 9:38 AM

    (You even remember anything Reagan said?)

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  6. LockwoodSeptember 28, 2009 at 10:05 AM

    Reagan was trying to repeat the famous aphorism "Facts can be stubborn things," but actually repeated it as "Facts can be stupid things."

    ReplyDelete
  7. BrentOctober 29, 2009 at 1:20 PM

    It sure looks like Von Karman vortices to me.

    ReplyDelete