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Reposting Pam's Odd Rock/Fossil - 2nd opinion?

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  • Reposting Pam's Odd Rock/Fossil - 2nd opinion?

    Pam, I'm reposting your odd rock because it continued to trouble me and I had a radical idea that I am floating here for anyone to weigh in with their opinions. Here's the rock or fossil or whatever it is:

    Now... I see shrinkage cracks towards the back, I see black glassy or crystalline material in the cracks so I'm thinking igneous, probably basaltic lava, probably pillow lava from rapid cooling as a result of molten rock meeting water. Igneous tells me it can't be a fossil so it has to be just an odd, weathered shape.
    Or is it?
    What occurred to me afterwards is that it is in fact possible to find fossils in igneous rocks (especially volcanic ones) if we stretch our definition of fossils just a bit. You may have seen these kinds of poignant casts of people who were buried in volcanic ash at Pompeii and Herculaneum from the eruption of Vesuvius in Roman times:

    Dogs, too:

    Even a loaf of bread, forever preserved in stone:

    But these were special circumstances weren't they? And these organic objects were mostly preserved as casts in deep layers of compacted volcanic ash. Well, that's true, but take a look at these examples which resulted from molten lava meeting something organic:

    What we have here is an assortment of seal pups and penguins that were swamped by a molten lava flow about 100 years ago on Barthalome Island in the Galapagos.
    Events like this are unusual, but not actually rare. Here's some examples from Hawaii:

    This is a Pandanas fruit cast in basaltic lava. It's a mere ten years old.

    This is obviously a fish, also cast in basaltic lava and a mere fifteen years old.
    Examples of this kind of formation are typically from recent eruptions but there are older examples too, like this (now empty) cast of a palm tree in basaltic lava which dates to around 2000 years ago.

      So, these are "igneous fossils" of a kind. Given the odd shape of Pam's rock, I just wonder if it is the result of lava smothering something organic and taking on that shape? Not recently of course. Also not a trilobite I feel, but I wonder what? Old knobbly bit of wood or something of the kind? I know that most of Ohio's basalt is truly ancient (pre anything likely to be organic) from the "Middle Run Formation", but have there been any more recent intrusions of lava? Anyone know?
    Watcha think?
    Roger
    I keep six honest serving-men (they taught me all I knew); Their names are What and Why and When and How and Where and Who.

  • #2
    Great pictures, Roger.
    Here's a link, (you may have all ready seen), provides a good simplified timeline of
    Ohios' geologic past.
    http://vulcan.wr.usgs.gov/LivingWith...past_ohio.html
    Volcanic activity is pretty darn old.
    Joe

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    • #3
      Lover this stuff.
      Jack

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      • #4
        Hey, Roger.  When I found the rock, I thought it was some sort of worm, or shelled bug.  I also thought it had a head and a body.  But seriously, I had no idea what-so-ever which is why I posted it.  Creepy looking sort, but not something I would leave behind.  Here are three more pics for a closer look at the other side of the rock.  Helpful, I hope.  Love to find interesting fossils!  Or whatever it is.
        Pam



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        • #5
          It does look like an insect head. Grasshopper or catapplier maybe. Very cool Pam

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          • #6
            Thanks Joe, that's really helpful. So, there was volcanic activity in Ohio in the Ordovician and again in the Devonian. That's "more recent" in my book and certainly recent enough to speculate that molten rock and organic material may have come together. Now that Pam has given us a side view, I am more convinced that lava has enrobed something organic, probably incinerated it and left a 3D cast behind. It doesn't look like just an odd shaped part of the rock, does it?
            But I wonder what? Maybe not trilobite... I couldn't find a species mentioned here that has a size and morphology which is consistent with Pam's find, but personally I wouldn't rule it out completely:
            http://www.dnr.state.oh.us/Portals/1...cts/geof05.pdf
            It has some resemblance to a mud lobster. It's definitely something. :blink: I love it.
            Pam: Is there a local natural history museum of any repute that you could take it to?
            Roger
            PS: Did you spot the complete penguin in my earlier pics?

            I keep six honest serving-men (they taught me all I knew); Their names are What and Why and When and How and Where and Who.

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            • #7
              Hey, Roger!  Sorry for the delay in a response...my Dad is visiting from NM and haven't had a spare moment until now.  Maybe the Ohio Historical Society?  I'll check it out when Dad heads back home.  It would be interesting and cool to get some info on my ugly bug!!!
              Pam

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