Fossil or Pseudofossil (Not Dendritic) from the Oregon Coast Range

[Hominid]

I found these rocks in the Oregon Coast Range (central to north) many years ago and have always wondered whether the interesting image was a pseudofossil or an actual fossil. If it's a pseudofossil, any ideas on how it would form? If it's a fossil, what on earth is it? The image measures about 37 mm at its widest point. I'm afraid that's all I know about it; the plane of view is unknown, although the right side could be tapering down to a stem/pedicel of some sort (or not). Web searches have proven futile. (Although probably wouldn't have if I knew what it was!)

 

Thanks for any insight you can provide!

 

 

 

 

Edited April 10, 2017 by Fossildude19
Added photos

[GeschWhat]

First let me welcome you to the forum! For some reason your images didn't show up. Do you mind posting them again?

[Hominid]

Thanks for the welcome, Lori! It's odd that the photos don't show at your end. They do here, but I'll post them again, and hopefully, they'll be visible to one and all.

Thanks for looking,
Dave

 

 

Edited April 10, 2017 by Hominid

[Rockwood]

Still polar bear eating marshmallows in a snow storm here.

[GeschWhat]

Same here...weird!

[EMP]

Try going to imgur.com. Click on the green "new post" button at the top, and upload your photos to that. Once you're done then copy the link of your photo uploads and paste the link here.

[Hominid]

Thanks! Hope this works.

 

If there are no images, here are the links...

 

<< http://imgur.com/sTPcMim >>

<< http://imgur.com/vcKJHVm >>

 

Dave

 

[Rockwood]

Has the look of a septarian concretion.

[Fossildude19]

Hmmm... can't access imgur from work.  

 

[fifbrindacier]

I agree it might be a concretion, but a weird one.

[ynot]

I do not see a concretion here.

Is the piece flat or mounded?

Tony

[GeschWhat]

That is really interesting. I have no idea what it is, but definitely intriguing. 

[Hominid]

Here's another photo with a close-up lens this time, although it doesn't reveal much more. I don't think it's a concretion;  there's essentially no dimensionality to the specimen.  It's almost as if it's drawn (but isn't) on a micrometers thick mud-colored surface on shale. Here's a link to Imgur, case it doesn't show up here: << http://imgur.com/a/6FbZP >>

Thanks for looking!

Dave

 

[GeschWhat]

Do you know if this is from a marine deposit? My money is on @abyssunder to figure this one out!

[Hominid]

I suspect so; the Coast Range resulted, in part, from uplift of oceanic rocks during the Miocene.

[Rockwood]

Cross sectioning rarely shows dimensionality. 

[abyssunder]

Well, it is still a mystery to me. It looks like a large foraminifera in cross section, but usually they are tiny. Can't be gastropod because of the chamber-like structure. Maybe mineral stains caused by efflorescence, minerals and salts left on the surface of the block by the evaporating water.

[Rockwood]

Any chance it may have been in a location where a lichen could have grown on it ? I can picture one etching a pattern like this. 

[GeschWhat]

Of course the shape is different, but it reminds me of the staining found in Mazon Creek concretions that is attributed to jellyfish. Did you split this or was it split when you found it?

[westcoast]

I'm leaning towards some bizarre kind of liesegang pattern...or certainly  some inorganic process.but I can't find anything even close. It would be so much easier if it had just been doodled by somebody using another stone but the dark internal 'structure' in the centre of the lighter area rules that out.

[piranha]

The UO ichnofossil specialist said it looks like Paleodictyon: an odd deep sea trace fossil.

Paleodictyon petaloideum is similar in appearance with meshes of unequal size and shape.

 

 

This is a unique and important discovery that UO has expressed an interest in acquiring.

Please contact me via PM if you would be interested in making a donation for research.

 

[westcoast]

Good to have an ID.

Just for final clarity...So the original raised ridges of the honeycomb structure of paleodictyon  have been abraded leaving the broad lighter coloured pattern?

[piranha]

1 hour ago, westcoast said:

Good to have an ID.

Just for final clarity...So the original raised ridges of the honeycomb structure of paleodictyon  have been abraded leaving the broad lighter coloured pattern?

 

UO:

Maybe.  Or maybe it was in a more friable matrix than usual.

 

 

[Kane]

And thanks to @piranha for facilitating contact. This seems very promising.

[Hominid]

Thanks for everybody's comments! Here's a bit more information: I collected the specimen when I was randomly cracking open rocks; you can see the G-pick marks on the right side, so no surface abrasion, evaporation, nor lichen growth. MOTM thought it looked like a large foram in cross-section and that was the first thing I thought of when I saw it, but dismissed the idea because of the usually diminutive size of forams, although now I see there are exceptions to that generalization and that they can reach 20 cm or more. On the other hand, the tapering seen on the right side of the image makes me wonder about the possible presence of a peduncle of some sort, either separated or in another plane, but maybe that's a red herring/my imagination. I like piranha's icnhofossil specialist idea of Paleodictyon petaloideum, although the drawing of it seems less organized to my eye than the voids in the mystery fossil. (You can take that with a grain of salt since I haven't attended a geology class in nearly 40 years, when I minored in the subject.)

 

By the way, when I copied the image onto the Google search box, Google concluded the image was of "jeans." Good for a chuckle, anyway.

 

Dave