Petrified Charcoal?

[Lindsey]

Is it possible for burnt wood to petrify and if so is that the case with these two rocks? They are both as solid and hard as a rock and do not flake, they both appear to have layers like I've seen in pieces of charcoal. If not can anyone tell me what they might be, as usual they were found in the North Suplhur River. I did a bad job with the photos tonight, if I need to take better ones I can.

[tracer]

i don't think permineralized charcoal is the issue here. "petrified wood" consisting almost purely of quartz can nonetheless come in various colors due to the presence of various other minerals. so "black" fossil wood is pretty common. the fossil wood i've found at nsr was all hazy/sandy and funky looking. it seems to have more of a largish microcrystalline structure rather than the much finer, basically invisible (cryptocrystalline) structure of the fossil wood i've found closer to home.

as far as do i think permineralized/pseudomorphed charcoal is possible, yeah, i guess, under perfect and rare conditions. a tree getting struck by lightning, burning into charcoal, falling over, and then a huge flood burying it in perfect conditions both to hold the charcoal together and to facilitate permineralization in an environment of high-dissolved-silica-content water percolating through it...

you wouldn't have the normal diagenetic boost for the fossilization because the organic bases for that would be gone already due to the burning. interesting thing to contemplate...

p.s. - the piece on the left looks like chert pseudomorphing of wood. the piece on the right could be well-worn fossil wood, but it might possibly be a tumbled piece of sedimentary rock of some kind. not sure, but probably also fossil wood.

[frozen_turkey]

The one on the right is just a rock. But the one on the left might be petrafied wood. Though it to might just be a rock.

-Frozen

[Lindsey]

Thanks for the info, one's got to be curious as I see it in the river quite often. The one on the right I was thinking rock because it doesn't look so much like wood on the flat surface, but the rest of it looks to be in layers which don't show up in the photos, guess it was the way the rock formed. But hey we've all got to learn, it's been sitting around figured I better go on and ask.

[tracer]

the one on the right may well be fossil wood. just hard to see the "grain" well enough to tell. some of the places i've found fossil wood have it in varying stages of morphing to "pure", unrecognizable chert, and after you look at a whole bunch of it, you start recognizing that some of the "rocks" started out as wood.

[Dave Bowen]

The NSR to the west has some high levels of phosphorus. You can find baculites and small ammonites that are charcoal black. That might be a factor in it's color, if it is petrified wood.

[Lindsey]

the one on the right may well be fossil wood. just hard to see the "grain" well enough to tell. some of the places i've found fossil wood have it in varying stages of morphing to "pure", unrecognizable chert, and after you look at a whole bunch of it, you start recognizing that some of the "rocks" started out as wood.

It's hard to explain the grain, I tried to take a better picture of it. It appears as if it was still soft you could flake pieces off, but I just can't get a good picture of the flaky side.

The NSR to the west has some high levels of phosphorus. You can find baculites and small ammonites that are charcoal black. That might be a factor in it's color, if it is petrified wood.

What you say could be true, we search the river in more of the Paris area so everything gets washed down river eventually.

[tracer]

yeah, that looks like wood to me. black coloration in fossil wood can be from carbon, manganese or i think sometimes even from the presence of iron. it doesn't take much of a particular oxide (or sulfide) to color fossil wood. you may have noticed in the past that a lot of mucky mud you get into has "blooms" of bacteria showing and also sometimes has a "swamp gas" smell. Hydrogen sulfide gas plays a big role in turning stuff black in such environments. if you turn over stuff laying on the ground in such environments, or dig down into the muck, you frequently see everything's all black. certain chemical processes seem to be prevalent in the formation of fossil wood that isn't formed purely through permineralization. it isn't all straightforward like that.

[Tony Eaton]

I've seen Cretaceous charcoal written in the literature for the Woodbine of Texas. I may have found some, but have not studied it. Perhaps charcoal is less common in non terrestrial, marine deposits?

Edited July 23, 2010 by Tony Eaton

[tracer]

I've seen Cretaceous charcoal written in the literature for the Woodbine of Texas. I may have found some, but have not studied it. Perhaps charcoal is less common in non terrestrial, marine deposits?

"carbonized wood" is definitely found as a state of preservation, but to me that's a different concept from "petrified charcoal". the specimen displayed here does not appear to me to be silicified charcoal, but i've been wrong before.

[grampa dino]

Yes it is possilbe to find burnt Petrified wood so there

[Lindsey]

Thank you everyone for all this info, although a bit mixed I still appreciate all thoughts on it.