Petrified Wood slab

[theArborist]

I have a 4" x 6" x 0.6" slab, collected in Arizona or New Mexico by my grandfather in the 1960s. It was cut and polished, now a pen holder.

I can clearly see the cellular structure. Is it possible to determine the type of plant/tree this was? I can do this for living trees, but I'm lost with trees from millions of years ago.

Also, there are some microscopic features that appear to be roots that were growing through the wood before silicification. Any thoughts or comments on these? See bottom left of 4th photo.

Finally, are there are resources I can use to answer these questions? Researchers, experts, etc whom I might contact?

Thanks for your help.

 

[Fossildude19]

There are experts, and that is what would be needed to say anything further about this, I believe.

Maybe @digit  or @piranha  can recommend someone.

[Coco]

@MarcoSr

 

Coco

[MarcoSr]

22 minutes ago, Coco said:

@MarcoSr

 

Coco

 

Really nice cell structure.  From what I see in the pictures, "longitudinal tracheids"and "resin canals", the wood is a softwood.  Hardwoods have a different basic cell structure.  You can use extant wood cell structure (see below extant softwood cell structure) to help identify a lot of fossil woods because fossil species can have extant related species.  However, softwood cell structures are very similar and only experts can really tell the softwoods apart.

 

 

 

Marco Sr.

 

[theArborist]

Thanks, Coco. I've been identifying extant wood for nearly 50 years, am quite familiar with cellular structure. I also suspect a coniferous species. The cells are distorted in many places, so have to be careful getting sizes and . There are also some sort of growth in many of the resin ducts, like a tiny root. Not sure exactly what they are. I can see cells in a few of them.

 

The stumbling point for me is that the slab does not have exposed radial or tangential surfaces to inspect, and I'm not sure I want to cut into this. I don't know enough yet about ancient species to guess at what this might be. I'm hoping to find some resources for U.S. Southwest to give me some clues as to what has been found there, and what to look for. Would like to get it to the genus level if I can.

 

This slab has been buried in my basement for 30 years (a little bit less than it was buried in the southwest). I just re-discovered it, and it rekindled my interest. My grandparents were rock hounds in their retirement, and did some amazing things. Here's a small axe in a stump, with obsidian blade and PW stump and handle. The stump is 2 inches wide. Used to have some split woo to go with it, but those pieces were lost.

[MarcoSr]

4 hours ago, theArborist said:

I don't know enough yet about ancient species to guess at what this might be. I'm hoping to find some resources for U.S. Southwest to give me some clues as to what has been found there, and what to look for.

 

The attached PDF will give you a general overview of fossil wood.  The "Bibliography" references a lot of other fossil wood papers that may be of interest.  I don't have a specific paper on US Southwest fossil wood.

 

 

Viney 2013 The Anatomy of Arborescent Plant Life through Time.pdf

 

 

Marco Sr.

Edited January 12 by MarcoSr
Added Bibliography reference

[theArborist]

Thanks for the help. Looks like a good intro to the topic.

[MarcoSr]

On 1/13/2024 at 1:34 AM, theArborist said:

Thanks for the help. Looks like a good intro to the topic.

 

I should have mentioned "Daniels Dayvault 2006 Ancient Forests A closer look at fossil wood" which is a pretty comprehensive book on fossil wood.  It has a very large number of incredible color pictures of fossil wood pieces through the ages found worldwide.  It also has a great many fossil wood cell structure pictures, but some of these pictures tend to be on the smaller side, for me at least, to fully grasp the structures.  An electronic version of the book would be better than the hard copy because you could blow up the cell structure pictures.

 

Marco Sr.

[paleoflor]

Beautiful photography and lovely rootlets!

 

Is the provenance ironclad? The overall preservation (mineralisation, colour scheme, etc.) reminds me of petrified wood from Saddle Mountain, WA. There also seem to be some fissures in the wood near the 6-o-clock position in first photo (correct ?) This could fit with bald cypress (for which the Saddle Mountain locality is well-known). 

 

P.S. The InsideWood database is an incredible resource for both recent and fossil wood identification. 

 

[theArborist]

MarcoSr: Thanks for the book suggestion. Someone else suggested it, so I ordered it. Incredible resource!

[theArborist]

Paleoflor: The provenance is NOT certain. Collected by my grandfather in the 1970s. My grandparents traveled the country in a Dodge van converted to rock-hunting and camping, and collected from many sites. I don't believe they kept any records of the sites or pieces collected.

[paleoflor]

Hi theArborist: If provenance is uncertain, you might want to compare your slab with examples of petrified wood from Saddle Mountain, WA-USA. As I wrote before, the overall mineralization pattern/colour scheme of the slab shows resemblance to material from that locality. See for example this specimen, or this one, or this one.

 

Are the structures encircled in yellow below physical gaps/fissures in the slab?

 

 

[theArborist]

Paleoflor: yes, those are fissures. I'm trying to decide if they might be decay pockets in the wood before petrification, or if they occurred later.

 

While reexamining the slab, I discovered an are that shows what I believe to be a stem bud that had not opened: red circled area and a CU image. The bud trace starts near the stem pith (left) and is 31 mm to the light part of the bud tip. At the right end of the bud trace is a fissure that breaks across the trace, and two small bud bracts on the sides of the trace. The preservation of such fine detail sorta blows my mind. I'm hoping this will help lead to a genus ID.