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Unknown Cambrian Feature from Oak Spring Trilobite Site


Sagebrush Steve

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I have been working through the trilobite specimens I dug recently at the Oak Springs Trilobite Site in eastern Nevada.  I came across this feature in the shale that I can't identify.  When I split the piece of shale I found this oval-shaped feature on both halves. It could be geologic or possibly some sort of fossil.  It has the same reddish color as some of the trilobites I found, but it's clearly not a trilobite.   When I turned one slab over I found the shape extended through the thickness of the slab (about 7 mm or 1/4 in thick) but was no longer a simple oval on the other side, it was much wider.  It did not extend through the thickness of the other half of the slab.  Anyone have any idea what this is? 

 

This is from the Combined Metals Member of the Pioche Shale.  The Combined Metals Member was named by the mining community.  Apparently this ore was fairly rich in silver, lead, and zinc sulfides and was mined heavily in the early part of the 20th century.

 

Here is the shape from the inside of the split slab (looks the same on both halves).  Scale in mm:

59da661908eb1_Unknown1.jpg.8bf61534dde6c49b2ebfa4c3d2851ec7.jpg

 

And here is what it looks like on the other side of the slab:

59da664089bbc_Unknown2.jpg.ca675a9ecdec2fa6ae727f683288e3c7.jpg

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The remnants of a bivalve shell in cross section ?

theme-celtique.png.bbc4d5765974b5daba0607d157eecfed.png.7c09081f292875c94595c562a862958c.png

"On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry)

"We only well see with the heart, the essential is invisible for the eyes."

 

In memory of Doren

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3 hours ago, fifbrindacier said:

The remnants of a bivalve shell in cross section ?

Could be possible.  That might explain why there is a distinct lighter colored outline around the whole outer edge--shell remnant?  And perhaps the thicker part along the bottom of the second photo is the hinge looking down from the top?  I know there aren't too many bivalve species in the Cambrian and I don't know if any have been found in the Pioche shale, but it is one possibility.

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Another possibility : some kind of early echinoderm, but that wouldn't explain the difference in thikness and shape.

theme-celtique.png.bbc4d5765974b5daba0607d157eecfed.png.7c09081f292875c94595c562a862958c.png

"On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry)

"We only well see with the heart, the essential is invisible for the eyes."

 

In memory of Doren

photo-thumb-12286.jpg.878620deab804c0e4e53f3eab4625b4c.jpg

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No expert, but it seems like knowing just how high up in the Cambrian this is would be important to the conversation. Aren't these tiny for most of it ?

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Yes, that would be important.

theme-celtique.png.bbc4d5765974b5daba0607d157eecfed.png.7c09081f292875c94595c562a862958c.png

"On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry)

"We only well see with the heart, the essential is invisible for the eyes."

 

In memory of Doren

photo-thumb-12286.jpg.878620deab804c0e4e53f3eab4625b4c.jpg

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I found a paper written by Dr. Bruce Lieberman of U Kansas in 2003 titled “A New Soft Bodied Fauna: The Pioche Formation of Nevada."  Since this is from the Pioche Formation and could be a soft bodied organism I emailed him to see if he could help identify it.  Have not yet heard back.  I am in one of the few parts of the town of Santa Rosa, California that isn't burning down right now but that could change, so it might be awhile before I can check in again.

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I just heard back from Dr. Lieberman.  @fifbrindacier, looks like you could be right:

 

Hi Stephen,

 Thanks very much for the email and the photos.  It is possible that this fossil does represent the remains of a soft-bodied organism, for instance, some kind of bivalved arthropod.  It somewhat has that appearance from the “top side” photo.  However, the “bottom side” photo is much more irregular in shape.  Probably I would say the best thing is to treat this as some kind of indeterminate, possible organic remain or mineral stain.  Truthfully it could be either one of those.  I would probably keep it though, just in case.  Also even if it’s not anything organic or directly referable to species, it does look kind of cool.  I know that is not a huge help, but it is the most I can state based on the photos so I hope it helps at least a bit.  Take care and all the best.

 

Sincerely,

Bruce

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On 10 octobre 2017 at 0:34 AM, Sagebrush Steve said:

I found a paper written by Dr. Bruce Lieberman of U Kansas in 2003 titled “A New Soft Bodied Fauna: The Pioche Formation of Nevada."  Since this is from the Pioche Formation and could be a soft bodied organism I emailed him to see if he could help identify it.  Have not yet heard back.  I am in one of the few parts of the town of Santa Rosa, California that isn't burning down right now but that could change, so it might be awhile before I can check in again.

I hope that you'll have no harm. I swear you good luck.

theme-celtique.png.bbc4d5765974b5daba0607d157eecfed.png.7c09081f292875c94595c562a862958c.png

"On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry)

"We only well see with the heart, the essential is invisible for the eyes."

 

In memory of Doren

photo-thumb-12286.jpg.878620deab804c0e4e53f3eab4625b4c.jpg

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2 hours ago, fifbrindacier said:

I hope that you'll have no harm. I swear you good luck.

Thank you very much.  At this point we have been evacuated but our home has not burned down.  Many others have not been so fortunate. We are staying at a local church for the next few days.

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On 10/11/2017 at 9:42 AM, Sagebrush Steve said:

Thank you very much.  At this point we have been evacuated but our home has not burned down.  Many others have not been so fortunate. We are staying at a local church for the next few days.

Thanks for the update. 

Be safe, Steve. :(  :fingerscrossed:

    Tim    -  VETERAN SHALE SPLITTER

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  • 7 months later...

Interesting... but I have two main worries about it being something good. The first is the orientation. To go vertically through such a thickness of shale without being totally squidged is unlikely; you're looking at a cross-section of something, here, rather than the flattened impression of something oval.

 

Second is that there's a thin curved line running through the middle and out both ends; I reckon that if there's a fossil here, then that's it, and the rest is a mineral halo. You say there are trilobites there; could it just be a bit of trilobite standing on end, with a mineral stain growing out through the rock around it? The way to be sure would be to split it vertically along that curved line... but you'd need to be pretty sure it was nothing interesting before doing that! ;)

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7 hours ago, Spongy Joe said:

Interesting... but I have two main worries about it being something good. The first is the orientation. To go vertically through such a thickness of shale without being totally squidged is unlikely; you're looking at a cross-section of something, here, rather than the flattened impression of something oval.

 

Second is that there's a thin curved line running through the middle and out both ends; I reckon that if there's a fossil here, then that's it, and the rest is a mineral halo. You say there are trilobites there; could it just be a bit of trilobite standing on end, with a mineral stain growing out through the rock around it? The way to be sure would be to split it vertically along that curved line... but you'd need to be pretty sure it was nothing interesting before doing that! ;)

Thanks.  I think I will leave it alone.  If anyone out there wants to access it as part of their Ph.D. Dissertation I would be happy to make it available. :)

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