Perhaps the traces shown indicate microbial activity of silicate lichens or algae.

Dear George,

such traces/microborings can be done by funghi, but sometimes also by sponges or algae. There is a good possibility that those traces are fossil ones, but not for sure. More information concerning the term "petrified" could be usefull.

Best regards

Johannes

Dear George

I think our two colleages are right; it is posible that these traces represent a type of microbial activity and/or the presenece of fugal hyphae; the smooth surfaces of the microtunnels are suggestive of either of these two possibilities. The opposite situation is to find for a kind of "micro-bite marks". A smoth Surface is more related to a fungal/microbial activity.

Sincerely

Rubén

Hi George

Looking at the size of the borings, and as suspected by the colleagues above, it appears that these are possibly microbial trace fossils caused by metabolic activities of microorganisms, the so called Euendoliths (Golubic et al. 1981). Best wishes.

Hello,

it seems to be a bioreosion feature probably made by either fungi, algae,etc...but:

• was it before permineralization of the wood, endophytes organisms living on the alive plant ?
• after the permineralization: endolithic organisms?

Dear George

Thank you for uploading these beautiful pictures. I am currently researching upon bioerosion on petrified wood, and the pictures you've uploaded seem as this may be the case in your fossils. I believe you have some sort of chemiolithotroph microorganisms.

I have some questions for you:

1) Did you clean, cut, polish or in any other way interfere with your samples prior to SEM-EDS observation and analysis?

2) Can you get some pictures from not cleaned fossil samples? What you have here is the traces of microorganisms. It would be nice if we could have a picture of the organisms themselves.

3) Have you spotted any difference in chemical composition when comparing the inner part of the traces and unharmed fossil?

4) What is the methodology you use in SEM?

I am looking forward to hearing from you. It would be nice if we could collaborate on this. I am studying some samples from Thailand, and up to now, I have noticed more than 20 different kinds of microorganisms. Part of that research has been presented in the 4th ARCH_RNT Archaeological Research & New Technologies  Symposium of Archaeometry in Kalamata, Greece. I have not cleaned my samples yet, but I am very curious to see if I can spot some traces after I've cleaned them.

Please feel free to contact me any time. You can also e-mail me at [email protected]. I am sure a possible collaboration can prove to be very fruitful!!!

Evangelia

PS: Escuse my bad English!!! I am just so thrilled that someone else has spotted traces of chemiolithotrophes on fossil wood using SEM!!!!

Evangelia,

Your work sounds interesting, thinks for responding.

This sample was just the outer surface of a small block of sandy sediment, just glued to a stub and sputter coated with Pd. No cleaning at all. The wood shard is late Miocene, mineralized with calcium phosphate. I have a lot of other wood specimens from this site, I haven't had time to go to the SEM lab to look at any more. I originally assumed the traces were made prior to fossilization, but I now suspect they were made by a microbe that was etching into the fossil wood, perhaps attracted by the high  phosphorus content.

Best wishes,

George

In that case you might be dealing with phospitobacteria.

Here are some sentences taken from my presentaion “Preliminary SEM-EDS Observations on Microorganisms present on Petrified Wood Samples from the possibly World’s Longest Fossil Tree”, at the 4th Symposium ARCH_RNT Archaeological Research & New Technologies:

There are several types of bacteria:  spherical (cocci), rod-shaped (bacilli), spiral (spirilla), comma-shaped (vibrios), corkscrew-shaped (spirochaetes) and they appear as single cells, pairs, chains or clusters. [.....] Chemiolithotrophic bacteria include phospitobacteria, nitrogen oxidizing bacteria, thiobacteria, nitrogen-fixing bacteria and iron bacteria. Phosphitobacteria are chemiolithotrophes that use inorganic compounds as reducing equivalents for energy or biosynthetic reactions. The reducing equivalent of phosphitobacteria is phosphite and the reaction involved is 4 PO32-  +  SO42-  +  H+  →  4 PO42-  + HS-.

I hope that helps. Let me know if I can do anything for you.