Triassic Cumnok(?) Formation, Fusain?

[Alejandro (Alex) Rosas]

Hi guys,
I did a lot of research to find out what on earth this is.

It contains clay and massive amounts of plant material (or I think it is plant elements). This material is unusual for me as it has a leathery texture and it is hyper glossy to the eye (picture below is only one side but all sides contain glossy material). It is rather odd so I placed it under the Stereo Micro to see if I could find some identifying features. This made things rather more confusing. On one side I found black (chrome like) very glossy material which looks like melted metal (comparison not real) but has plantae features to it. When I turned it around for another perspective thing got more complicated as it resampled fish scales. If you look at the picture with the whole specimen it has the leathery glossy material I mentioned which is the one under the micro which has scaly look to it. I do apologize for the Micro Pics I do not have an adapter yet they were taken with my phone.

To make this short the only thing I could find that resemble this are specimens of Fusain collected in Pennsylvania. In North Carolina’s Deep River Basin there is only one Formation which has commercially mined coal, The Cumnock Formation. Where I found this specimen there are clear signs of the Pekin and Sanford Formation and in-between there are organic rich shales directly below the spot where I found this (resembling the Cumnock Shales). The only problem is that I am way south of the known exposures off this formation (50 miles). Continuing my research, I found out that a Pekinosaurus olseni (Revueltosaurus as later discovered) which was found 50 yards north of this exposure and for which his name was given based on the Pekin Formation was lateron discovered that it was actually laying in a southern extension of the overlying Cumnock Formation (Heckert et al). I mention this because Fusain is usually found above coal. My eyes are putting to many names to this so I decided not to look further and to ask for help.

Any help guys @rleder @egardner ?

PS: Ronny my sincere congratulations on your newborn!

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[Dr. Ronny Maik Leder]

Hey Alex (@alex-rosas), I see what you are talking about and this kind of structure can easily be misinterpreted as fossil, but it seems to me that it is just a mineral structure (lacquer or coating) from iron oxide (probably pyrite) or marcasite. I have seen lot of these structures but most of the time it was just from mineral origin. Sometimes real organic material (like tree leaves) attract such minerals so that the minerals get accumulated in the organic structure and replace it. But then you still should see the leaf structure like venation etc. But like I said earlier, such examples are a very good way to understand how complex this field is and how much we have to take a closer look until we can state: yeah this is fossil!

Thank you for sharing it!

All the best

Ronny

btw: thank you for the congrats 🙂

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