The stuff from the Bearpaw formation no one talks about

[LabRatKing]

These came to my personal collection from an auction at a high school that shut down. Normally I prefer to dig my own, but these were too cool to ignore at a buck each.

 

I got lots of other science stuff too! Nothing like picking up a few goodies on the side while buying glassware and microscopy stuff for work!

 

 

[jpc]

wood from the Bearpaw.... I don't think I have ever seen that, but then most of my time is spent south of the MT/WY border, where we call it the Pierre Shale.  

[Norki]

Wood is one of the most common fossils found in the Bearpaw deposits here in SK (both silicified and carbonised). That's interesting to hear that it doesn't occur as much further south. I wonder why that is?

 

It must have to do with the proximity of the deposits to the paleo coastline, because I've even found leaves before, like this Merispermites:

 

 

Those Ophiomorpha burrow casts are also super iconic of the Bearpaw formation around here. Also associated with near-shore deposits... I think I'm starting to see something of a correlation here.

[LabRatKing]

Yeah usually on this end all one hears about is the ammonites it seems. I'm intrigued buy how coal-like the wood is. The Ophi casts are just as sandy as they look, yet hard and stable.

 

As @jpcsaid I'm used to the Pierre shale end.

[Norki]

The carbonized stuff pretty much ranges from a crumbly bitumen (more rare) to an extremely fibrous lignite (most common) with exceptional detail and preservation. The stuff often looks and feels like regular wood, which seems funny when you notice that it's encrusted in selenite or hard sandstone.

 

 

I'm pretty convinced that the wood has something to do with these sites being from near-shore deposits (a few years ago a buddy and I actually tuned the Royal Sask. Museum to a site we found that's now on their radar as being a lagoon deposit). Also worth noting is how incredibly well-preserved the stuff that you find inside the calcareous sandstone concretions of this formation is... Of course there's the extremely well preserved, nacreous ammonites that the Bearpaw is famous for, but almost everything else that's found in those sandstone concretions is also preserved remarkably well.

[FranzBernhard]

2 hours ago, LabRatKing said:

I'm intrigued buy how coal-like the wood is.

Is this particular specimen both in one: part coalified, part petrified?

Franz Bernhard

[LabRatKing]

2 hours ago, FranzBernhard said:

Is this particular specimen both in one: part coalified, part petrified?

Franz Bernhard

I don’t know if I’d cal it coal just yet, but it is close! Norki explains above.

[LabRatKing]

@Norki wow. I had no idea. It turns out these specimens were from a now defunct educational supplier stateside that specialized in fossils and were distributed by Ward’s to schools. 
 

I think I need to research this area as from what I see there is a pretty cool ecosystem preserved up there!

[FranzBernhard]

1 hour ago, LabRatKing said:

I don’t know if I’d cal it coal just yet, but it is close!

Thanks! Yes, clearly lignite (var. Xylite) in @Norki´s pic.

 

I am using the terms a little bit different over here.

For me, coal is diagenetically overprinted organic matter, irrespective of rank. Lignite, subbituminous coal, bituminous coal - everything, that can be combusted/burned is coal.

The other thing is petrified - organic matter replaced by silica etc.

I see often the term carbonization there on TFF. This is for me restricted to coal formation by great heat, resulting in charcoal, fossil or recent, does not matter.

 

So concerning the specimen above, one part of it seems combustible, the other not?

 

Here are examples of partly coalified, partly lithified wood specimens of subbituminous rank from my area:

When polished, you can see continuous wood grain in coalified and lithified part.

Franz Bernhard

[FranzBernhard]

6 hours ago, Norki said:

pretty much ranges from a crumbly bitumen (more rare) to an extremely fibrous lignite (most common)

Crumbly bitumen: This could also be gelified wood (also sometimes called Dopplerite). Xylite and Dopplerite can occur side by side.

Franz Bernhard

[LabRatKing]

2 hours ago, FranzBernhard said:

Thanks! Yes, clearly lignite (var. Xylite) in @Norki´s pic.

 

I am using the terms a little bit different over here.

For me, coal is diagenetically overprinted organic matter, irrespective of rank. Lignite, subbituminous coal, bituminous coal - everything, that can be combusted/burned is coal.

The other thing is petrified - organic matter replaced by silica etc.

I see often the term carbonization there on TFF. This is for me restricted to coal formation by great heat, resulting in charcoal, fossil or recent, does not matter.

 

So concerning the specimen above, one part of it seems combustible, the other not?

 

Here are examples of partly coalified, partly lithified wood specimens of subbituminous rank from my area:

When polished, you can see continuous wood grain in coalified and lithified part.

Franz Bernhard

 

2 hours ago, FranzBernhard said:

Crumbly bitumen: This could also be gelified wood (also sometimes called Dopplerite). Xylite and Dopplerite can occur side by side.

Franz Bernhard

Roger that!

This is the perfect excuse to find out the answer.

I have this specimen on the shelf in my office, so I’ll take a bit to the lab and run some tests.

 

only reason I got into science is to play with fire legally!

 

<insert crazy laugh here>

[jpc]

10 hours ago, LabRatKing said:

Yeah usually on this end all one hears about is the ammonites it seems. I'm intrigued buy how coal-like the wood is. The Ophi casts are just as sandy as they look, yet hard and stable.

 

As @jpcsaid I'm used to the Pierre shale end.

now that I think about it, I do find occasional bits of wood in my ammonite concretions.  Just not nearly as nice as the one you posted, and completely friable.  

[FranzBernhard]

I have posted this several months ago, maybe it is of interest also in this topic:

Franz Bernhard

[LabRatKing]

SO, I took a small sample from the specimen and put it to the test.

 

It doesn't show well in the photos, but there is small veins of calcite/silica type minerals running through it.

The black portions can best be described as spongey-glassy. Streaks black on tile (no surprise). Mohs range 3-4.

 

I honestly expected it to burn at least a little, but I was unable to get any char or ignition using propane or natural gas.

However, there was what is probable the most stable orange flame test spectra I have ever seen...were talking more in the Fe(III) range than the Sc.

I tried it under torch, and in a crucible. Result did not change Mohs hardness noticeably, but resulted in a silvery-gray color.

 

I have my GCMS and FTIR down for quarterly maintenance, but we will run some of that in coming weeks as my biochemists are all excited about this.

 

(photos to follow in next post)

[LabRatKing]

[LabRatKing]

I’m just guessing here but I think the black color is likely due to various iron compounds with the usual calcium/sodium/silicates mix we se in many sedimentary rocks.

 

But some serious machine tests will tell for certain.

[FranzBernhard]

That´s a fine documentation of your work, thank you!

The specimen you tested is fossil wood, that´s clear.

Question is, what is it composed of? I am guessing, that the black color is from relic organic matter, with inorganic matter (minerals) vastly dominating. But machines will tell, yes.

Franz Bernhard

[Norki]

@LabRatKing

For what it's worth I've also found pieces of fossil wood in the Bearpaw that were partly lithified and partly coalified, so there's some precedent to assume that your piece might be the same.

[LabRatKing]

I wish I had a tube furnace and a flame spectrometer here, but materials testing isn't something we do. However the FTIR will help a little after some sample processing (gotta grind it up super fine and hope that at least some of the stuff reacts to infrared.

 

We are formulating a plan to process samples for GCMS. I don't think HPLC is a good option here as getting this stuff into solution would change the constituents too much to be worth the effort.

 

I can try some UV-Vis too, but again I think sample processing would result in skewed results...however, I am confident that by next week we can get some more detailed materials testing analysis to at least make a good guess.

 

Good news is I have about 15 different samples of "coal" here, from straight up crude oils and asphalt right on up into lignite and anthracite and everything in between and so on to compare it to.

[FranzBernhard]

In your case of fossil wood, a polished section and reflected light microscopy would also be an option. Organic and non-organic constituents can be easily distinguished that way.

10 hours ago, LabRatKing said:

Good news is I have about 15 different samples of "coal" here, from straight up crude oils and asphalt right on up into lignite and anthracite and everything in between and so on to compare it to.

Yes, that is always a big bonus to have something for comparison .

 

@Norki, @LabRatKing, I am wondering, if any detailed literature exists about fossil wood in the Bearpaw formation. That xylite is quite unusual for Upper Cretaceous sediments, I think. Such fibrous stuff normally still contains some cellulose. 

 

Franz Bernhard

[Norki]

1 hour ago, FranzBernhard said:

I am wondering, if any detailed literature exists about fossil wood in the Bearpaw formation. That xylite is quite unusual for Upper Cretaceous sediments, I think. Such fibrous stuff normally still contains some cellulose. 

 

Franz Bernhard

That's interesting about xylite containing cellulose, I didn't know that.

 

As for your question, I haven't come across any literature specifically about fossil wood, but in this 1968 report on the Bearpaw formation in the South Saskatchewan river valley, W.G.E Caldwell has this to say:

 

 

I am also in contact with a paleontologist who is studying marginal marine sites of the Bearpaw formation (particularly where it intertongues with the Dinosaur Park Formation), and is interested in visiting the location I found that leaf fossil. Incidentally, that xylite in the second photo I shared is from the same site as the leaf - do you think that an analysis of the wood would give a clearer picture of the depositional context? I'll have to ask if the presence of xylite will be given much consideration in the study.

[FranzBernhard]

Thanks so much for the info and the excerpt, @Norki!

I don´t think that the xylite directly says something about the depositional context. But it could say something about diagenesis etc.

And at least it could be checked for cellulose content. If some cellulose is still there, this cellulose could give some paleoenvironmental data via stable isotopes (as far as I can remember, just talk with the pros).

Franz Bernhard

[LabRatKing]

12 hours ago, FranzBernhard said:

In your case of fossil wood, a polished section and reflected light microscopy would also be an option. Organic and non-organic constituents can be easily distinguished that way.

Yes, that is always a big bonus to have something for comparison .

 

@Norki, @LabRatKing, I am wondering, if any detailed literature exists about fossil wood in the Bearpaw formation. That xylite is quite unusual for Upper Cretaceous sediments, I think. Such fibrous stuff normally still contains some cellulose. 

 

Franz Bernhard

I'll have to dig around a bit and see. I also have some small samples digesting (my wife was very happy I brought home chemicals and such to play with my rocks over the long holiday weekend here...)

This stuff at a glance appears to very pourus in structure, I kind of wish I had some of the fibrous specimens to play with. I may have to see about purchasing some.

 

I plan to do some sections for microscopy next week! Had to get a replacement cutter blade and the holiday delayed my plans.

I am intrigued at the light absorption capabilities and am curious if it is a result of structure or chemistry. Blackest blacks are always fun. Plus, I am always looking for new possible substrates for the cell culturing I am working on.

[LabRatKing]

11 hours ago, Norki said:

That's interesting about xylite containing cellulose, I didn't know that.

 

As for your question, I haven't come across any literature specifically about fossil wood, but in this 1968 report on the Bearpaw formation in the South Saskatchewan river valley, W.G.E Caldwell has this to say:

 

 

I am also in contact with a paleontologist who is studying marginal marine sites of the Bearpaw formation (particularly where it intertongues with the Dinosaur Park Formation), and is interested in visiting the location I found that leaf fossil. Incidentally, that xylite in the second photo I shared is from the same site as the leaf - do you think that an analysis of the wood would give a clearer picture of the depositional context? I'll have to ask if the presence of xylite will be given much consideration in the study.

I am attempting some demineralization from this specimen as I write, however, due to its time above ground it is "bone dry" so to speak. In hindsight, I should have tried rehydration of a few samples too. I'll add that to the list. In the case of this specimen if any xylite was present, it has long since dessicated.

[FranzBernhard]

10 hours ago, LabRatKing said:

This stuff at a glance appears to very pourus in structure,

This is quite unusual for fossil wood, isn´t it?

Possibilities:

- It has gone through a wildfire of unspecified temperature.

- It is partly replaced by calcite, which has been partly dissolved. Did you do an acid test?

Franz Bernhard