48 million year old fossilised wood of Schinoxylon sp.

Bruce Williams · Post by **Bruce Williams** » Tue Mar 13, 2007 5:26 pm

Hi folks,

This is a posting to both forums.

You are looking at a piece of fossilised branch (~5cm in diameter and 10cm long). It comes from the Green River Formation in the Blue Forest area of SW Wyoming. Fossils from this formation are known to be ~48 million years old. The presence of resin ducts lying along the medullary rays rather than following the line of the tree rings indicate that this is a Schinoxylon sp. (a member of the cashew family, Anacardiaceae).

The fossil weighs 502g.

The blue/gray areas are agate. Tree rings and cellular structure as well as some of the bark detail has survived fossilisation - see posting in Microscope Forum:

http://www.photomacrography.net/forum/v ... 1742#11742

Bruce

MacroLuv · Post by **MacroLuv** » Wed Mar 14, 2007 12:36 am

Amazing piece of fossilized wood. Looks like some parts are older than others.

Maybe there are fossilized worms inside.

How about investigate it with CT (computed tomography) or other appropriate method?

beetleman · Post by **beetleman** » Wed Mar 14, 2007 9:19 am

That sure is a nice piece of fossilized wood Bruce and the microphotographs are even better. You can sure see the sap veins. Have you counted the rings yet?? If you don`t RiK probably will (he will just want to know!)

Adrian · Post by **Adrian** » Wed Mar 14, 2007 11:14 am

awsome, ive allways been so facinated with fossilized wood, it is such an amazing natural process

Bruce Williams · Post by **Bruce Williams** » Wed Mar 14, 2007 1:09 pm

Thanks for your comments guys.

Nikola - It's not at all uncommon to find fossilised evidence of bug infestation. Steve Valley would be the expert here, but I have fossilised wood with tunnels and chambers that look like they were made yesterday. I'll post some pics sometime soon.

Doug - Not the easiest piece to do a ring count as the medullary rays tend to dominate everything else within the photo (not so much thru the microscope eyepiece) - interesting idea though - I may have to experiment with the lighting to try and emphasise the rings

.

Adrian - Absolutely - and there is so much variation due to the almost limitless permutations of timescale, chemistry, species, location and the actual fossilisation process itself.

Bruce

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Wed Mar 14, 2007 7:05 pm

My grandmother (a woman limited to an 8th grade education, but boundlessly curious about the world) gave me a rock very similar to this when I was a child, telling me it was a stalactite/stalagmite from a cave....The bark wasn't as distinct as your specimen, so I always accepted that (how could Grandma be wrong?!"). Now I'm going to have to find that rock amongst all my dusty boxes of mementos, and see if it is actually petrified wood.

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Wed Mar 14, 2007 7:07 pm

Bruce Williams wrote: The presence of resin ducts lying along the medullary rays rather than following the line of the tree rings indicate that this is a Schinoxylon sp. (a member of the cashew family, Anacardiaceae).

I'm ignorant about anything that doesn't have a pulse, but curious (like Grandma!) can you relate what we see in the fossil to the sentence above?

Bruce Williams · Post by **Bruce Williams** » Thu Mar 15, 2007 11:50 am

Mike - If your Grandma's gift does turn out to be a stalactite or stalagmite as she thought, it will still be an interesting piece and worth photographing. I for one would be very interested to see a sawn and sanded cross section, prepared along the lines of the concrete in Rik's recent posting.

I'll try and answer your question about the resin ducts etc - although its a huge subject and I'm certainly no expert. Firstly, if you haven't already done so I suggest you check out the related Microscope Forum posting "Cell and ray detail in 48 million year old fossilised wood" which shows details of the medullary rays and cell structure:

http://www.photomacrography.net/forum/v ... php?t=2016

Identification of fossil wood is usually based on similarities with living species and fortunately there are a number of books on the subject of identifying modern woods. A good and faily cheap "starter" is "Identifying Wood: Accurate Results with Simple Tools" by R. Bruce Hoadley. If you've got the money a really great book on the subject of identifying fossilised wood is, "Ancient Forests" by Frank Daniels and Richard Dayvault.

Of particular significance is the look/structure of the bark and (when viewed in cross section) the grain pattern produced by the annual rings and the medullary rays (radiating from centre to bark). The presence/colour/transition of earlywoods and latewoods and the presence and arrangement of earlywood/latewood pores are also very important factors in pinning down the species of tree ....and of course there are many more identifying characteristics that may helpfully be looked at - eg, resin ducts.

If present, resin ducts (see pic2, Microscope Forum posting) can either be radially or axially oriented and typically are shaped like drawn out ovals. Now the chap that I bought this "log" from (a major supplier of fossil wood) obviously considered the presence and arrangement of the resin ducts to be particularly diagnostic of a Schinoxylon species as he singled out that observation to be included on the specimen card that came with the fossil wood.

Hope that helps a bit.

Bruce

cactuspic · Post by **cactuspic** » Thu Mar 15, 2007 10:09 pm

Good shot of an interesting subject. I have a huge petrified log in my front yard that came with the house when we purchased it in 1981. Now I am curious to see what it looks like inside.

Irwin

Bruce Williams · Post by **Bruce Williams** » Fri Mar 16, 2007 1:43 pm

Irwin - Whole logs cost an arm and a leg in the UK. Some folks even have them standing upright inside the house as prized items of décor.

Bruce

Danny · Post by **Danny** » Sat Mar 17, 2007 5:55 am

Amazing details Bruce and remarkable shot !!. Very, very clever work and fascinating. Thanks for the info, these sort of posts makes it all worth while.

Danny.

Mike B in OKlahoma · Post by **Mike B in OKlahoma** » Sat Mar 17, 2007 10:46 am

Bruce Williams wrote:Mike - If your Grandma's gift does turn out to be a stalactite or stalagmite as she thought, it will still be an interesting piece and worth photographing. I for one would be very interested to see a sawn and sanded cross section, prepared along the lines of the concrete in Rik's recent posting.

It wasn't sawn and sanded, but the ends were cut. My recollection is of a rock that looked like milky quartz, but I haven't laid eyes on it probably in at least twenty years, so not positive. I'm going to have to look for it!

Bruce Williams · Post by **Bruce Williams** » Sun Mar 25, 2007 4:27 pm

I haven't checked this posting for a while and so missed the last 2 replies. So my apologies to Danny and Mike for not replying sooner.

Your very supportive comments are really greatly appreciated Danny - IMO it's the people as much as the postings that make the forum!

If you do find it Mike there are a number of small companies on the web that will cut and polish it for you at quite reasonable prices.

Bruce

Cyclops · Post by **Cyclops** » Mon Mar 26, 2007 8:01 am

Fascinating Bruce, being a palnt lover I would love to find something like this!

48 million year old fossilised wood of Schinoxylon sp.

48 million year old fossilised wood of Schinoxylon sp.

Re: 48 million year old fossilised wood of Schinoxylon sp.