Soft wood found in blasted rock

[Kellydm15]

This was found in blasted rock with shells, geodes on Vancouver Island. It is covered in some very thin hair like crystals and larger more solid quarts like crystals. It has a wood grain, very dark, charcoal like. I originally thought petrified wood but it is soft if you press your nail into it. Can anyone identify it for me? Thanks! 

[Thomas.Dodson]

17 minutes ago, Kellydm15 said:

This was found in blasted rock with shells, geodes on Vancouver Island. It is covered in some very thin hair like crystals and larger more solid quarts like crystals. It has a wood grain, very dark, charcoal like. I originally thought petrified wood but it is soft if you press your nail into it. Can anyone identify it for me? Thanks! 

Wood seems correct. "Petrified" might not be the correct term in this case since that usually refers to wood completely permineralized or replaced with hard minerals. Lignin often remains in fossil wood in varied levels. In this case I'd imagine there is less hard mineral replacement and more lignin. I see poorly permineralized bits of wood like this in many marine deposits in North Dakota. Some of it is basically wet pulp and others act like old matchsticks or simply sawdust.

[Rockwood]

29 minutes ago, Kellydm15 said:

, charcoal like

Charcoal is quite stable. And it also looks a lot like charcoal. 

[Kellydm15]

14 minutes ago, Thomas.Dodson said:

Wood seems correct. "Petrified" might not be the correct term in this case since that usually refers to wood completely permineralized or replaced with hard minerals. Lignin often remains in fossil wood in varied levels. In this case I'd imagine there is less hard mineral replacement and more lignin. I see poorly permineralized bits of wood like this in many marine deposits in North Dakota. Some of it is basically wet pulp and others act like old matchsticks or simply sawdust.

And this can occur even even everything else has basically fossilized? So it’s still very old but has maintained some organic matter vs turning to a harder material? 

[Rockwood]

23 minutes ago, Rockwood said:

quite stable

Perhaps geologically stable would be more accurate. Well over the arbitrary age set to represent a fossil. 

[Kellydm15]

8 minutes ago, Rockwood said:

Perhaps geologically stable would be more accurate. Well over the arbitrary age set to represent a fossil. 

Interesting! So caused by an ancient fire I assume?

[Thomas.Dodson]

6 minutes ago, Kellydm15 said:

And this can occur even even everything else has basically fossilized? So it’s still very old but has maintained some organic matter vs turning to a harder material? 

Correct. As an example I often find similar wood in Fox Hills sandstone concretions with other perfectly preserved fossils (my avatar for instance).

 

I once threw some concretion pieces from the Fox Hills site my avatar is from into hydrochloric acid to get a better idea of how much wood was in some of the concretions. The lignin/less replaced wood resists the hydrochloric acid while the sandstone and other fossils get eaten by it. The end result is this.

 

Here's another example of very soft fossil wood from a sandstone concretion I collected in the Cannonball Formation last week. This one has been exposed to the elements a bit too long.

I accidentally dropped it after the picture and this much fell off. These give you an idea of how fragile, soft, and variable pieces of wood can be depending on the amount of mineral replacement, the type of mineral replacement, and lignin.

[Kellydm15]

11 minutes ago, Thomas.Dodson said:

Correct. As an example I often find similar wood in Fox Hills sandstone concretions with other perfectly preserved fossils (my avatar for instance).

 

I once threw some concretion pieces from the Fox Hills site my avatar is from into hydrochloric acid to get a better idea of how much wood was in some of the concretions. The lignin/less replaced wood resists the hydrochloric acid while the sandstone and other fossils get eaten by it. The end result is this.

 

Here's another example of very soft fossil wood from a sandstone concretion I collected in the Cannonball Formation last week. This one has been exposed to the elements a bit too long.

I accidentally dropped it after the picture and this much fell off. These give you an idea of how fragile, soft, and variable pieces of wood can be depending on the amount of mineral replacement, the type of mineral replacement, and lignin.

Wow! This is so interesting! I had no idea this could happen. Thanks so much for all of the information.

[Creek - Don]

Looks like coal    I also found large coalified wood from Cretaceous Austin Chalk formation limestone few years ago.   One of those large tree trunk got trapped at the bottom of the Western Interior Seaway about 80 million years.     Left is a lignite (Eocene)  and one on the right is a coal (Cretaceous)  found in the limstone picture below.  

 

 

 

 

Edited July 11, 2021 by Creek - Don

[Rockwood]

All these suggestions seem quite valid. I suspect that it would take a keen eye to even begin to differentiate them in a photo.

[Rockwood]

3 hours ago, Kellydm15 said:

Interesting! So caused by an ancient fire I assume?

Some pieces I collected in Carboniferous aged rock were ID as probable evidence of just such an occurrence. Apparently there were times in the past when the elevated oxygen levels promoted more vigorous fires which would burn through even swampy environments to a greater extent than seen today.

[Ludwigia]

By the way, the minerals could very well be gypsum.

[Kellydm15]

5 hours ago, Ludwigia said:

By the way, the minerals could very well be gypsum.

Oh, I didn’t realize gypsum could be so dark. I’ve only ever seen grey to white gypsum before. 

9 hours ago, Creek - Don said:

Looks like coal    I also found large coalified wood from Cretaceous Austin Chalk formation limestone few years ago.   One of those large tree trunk got trapped at the bottom of the Western Interial Seaway about 80 million years.     Left is a lignite (Eocene)  and one on the right is a coal (Cretaceous)  found in the limstone picture below.  

 

 

 

 

Wow! These are beautiful finds! 

[Ludwigia]

8 minutes ago, Kellydm15 said:

Oh, I didn’t realize gypsum could be so dark. I’ve only ever seen grey to white gypsum before.

Chemical or mineral impurities can be built into the crystal lattice causing all kinds of colors, depending on which mineral, to occur in what would normally be a clear crystal. You can also observe that with quartz and calcite for example.

[FranzBernhard]

Looks very much like charcoal, @Kellydm15.

 

The coal petrographic term would be "Fusain". Most commercially mined coals contain a few volume percent of fusain as minute particles intermixed with the other coal components. 

Fusain (link to wikipedia, with a very nice pic!)

Franz Bernhard

[DPS Ammonite]

18 minutes ago, FranzBernhard said:

Looks very much like charcoal, @Kellydm15.

 

The coal petrographic term would be "Fusain". Most commercially mined coals contain a few volume percent of fusain as minute particles intermixed with the other coal components. 

Fusain (link to wikipedia, with a very nice pic!)

Franz Bernhard

When you look at black crumbly wood in the first photo or wood found in the Cretaceous rocks of Texas, how to you tell the difference between coalified vs. charcoal wood?

[FranzBernhard]

1 minute ago, DPS Ammonite said:

When you look at black crumbly wood in the first photo or wood found in the Cretaceous rocks of Texas, how to you tell the difference between coalified vs. charcoal wood?

I was considering the fibrous and porous texture, the black color*, the slight gloss and the softness - "It looks very much like charcoal." 

*Color should be checked! Whats the color of a very fine powder of this specimen, @Kellydm15? If it is not black, it is not fusain, of course, and I am wrong!
Franz Bernhard

[Kellydm15]

2 hours ago, FranzBernhard said:

I was considering the fibrous and porous texture, the black color*, the slight gloss and the softness - "It looks very much like charcoal." 

*Color should be checked! Whats the color of a very fine powder of this specimen, @Kellydm15? If it is not black, it is not fusain, of course, and I am wrong!
Franz Bernhard

The very find powder is black! My first thought when looking at it was burnt wood, so charcoal would make sense?

[FranzBernhard]

11 hours ago, Kellydm15 said:

The very find powder is black! My first thought when looking at it was burnt wood, so charcoal would make sense?

Ok, seems indeed to be fusain.

Yes, incompletely burnt wood (the black pieces you my find in a campfire, for example) is charcoal. Completely burnt wood is - ash .

But note, the properties of fossil charcoal might not be completely the same as fresh charcoal. Consider tens of millions of years sitting in the ground under several hundred or thousand meters of overburden in a water-saturated sediment. This may change some properties.

Franz Bernhard

[Rockwood]

16 hours ago, FranzBernhard said:

"Fusain"

As I recall, many of the fine details of extinct plant anatomy have been gleaned through study of tiny examples that were preserved this way.