Curious about iron and pyrite in the Hell Creek Formation

[Maniraptora]

Hey all! When I went on a collecting trip in the Hell Creek Formation in Montana, there were many iron concretions, and I've noticed that some specimens from there appear to be iron-stained. This makes me wonder if pyrite could be among the minerals involved in fossil preservation there. Are some of the bones found in the Hell Creek pyritized, and how could those be distinguished from others preserved differently? If so, do those Hell Creek specimens ever develop "pyrite disease," and what would be the warning signs to look out for?
Thanks so much for sharing your knowledge!

[Bobby Rico]

6 minutes ago, Maniraptora said:

pyrite disease,

I don’t know to be honest but I think pyrite disease can be caused in the improper storage of the specimen. Specimen that are kept in damp conditions or not fully dry and stored in Tupperware or poly bags . The only diseased specimens I have had was stored in polly bags. Other fossil from the same location but stored on shelves no problems so far . Probably no help with your question sorry pal.

[hadrosauridae]

I cant speak for all specimens.  The fossils I have seen with pyrite were patchy.  It doesnt look like "gold" pyrite, it looks black and extremely rough in texture.  Not all pyrite results in pyrite disease and I dont know if the HC specimens are prone to it but I suspect they are.

 

Pyrite disease can not be prevented.  Very humid conditions can cause it to happen faster, but tests done, and observations with pyrite over years have shown that the decay process can not be stopped.  It can be slowed, delayed, but never stopped.  The fossil can be vacuum sealed in plastic and it will still happen.  There are some chemical treatments you can use to remove the oxidized pyrite, but it only treats a shallow layer and has to be repeated, forever (or nearly for human life cycles) possibly.

[Oxytropidoceras]

Ullmann et al. (2017:791) stated of the Standing Rock Hadrosaur Site bonebed in the Maastrichtian Hell Creek Formation of South Dakota:

 

"Five of these pyritic concretions also permeate portions of interior bone, creating local zones of permineralization. Incipient pyrite

‘‘disease’’ is beginning to degrade some of these specimens, in which the pyrite concretions are friable and crumble when touched."

 

Looks like at this site, it occurs when pyrite concretions are attched to the fossil bone.

 

Reference cited:

 

Ullmann, Paul V., Allen Shaw, Ron Nellermoe, and Kenneth J. Lacovara.

"Taphonomy of the Standing Rock Hadrosaur Site, Corson County,

South Dakota." Palaios 32, no. 12 (2017): 779-796.

 

More PDFs of papres by Paul V Ullmann,Rowan University, Department of Geology

 

Yours,

 

Paul H.

Edited January 14 by Oxytropidoceras
added text

[Maniraptora]

Thanks for the helpful info! That's pretty frustrating that there's no way to prevent this. I guess a lot of specimens will eventually become "lost to science" via pyrite.

 

How would I recognize the very beginning stages of pyrite disease if it was happening to a specimen? I have one bone fragment where the cortical bone seems to have darkened in color (from light beige to... very slightly less-light beige) and gotten a bit shinier, but the difference doesn't seem to photograph and makes me wonder if I'm just noticing the way it always looked.

[hadrosauridae]

I'm not sure there is anything noticeable until it begins to crumble.

[FranzBernhard]

5 hours ago, Maniraptora said:

How would I recognize the very beginning stages of pyrite disease if it was happening to a specimen?

Smell. A faint smell of sulfur dioxide.

Would you like to show off the specimens in question anyways?

Franz Bernhard

Edited January 14 by FranzBernhard

[Maniraptora]

8 hours ago, FranzBernhard said:

Smell. A faint smell of sulfur dioxide.

Would you like to show off the specimens in question anyways?

Franz Bernhard

Well, it definitely smells like... nothingness. So I guess that's a good sign! I can't upload pics at the moment, though. One detail I've noticed about this specimen is that the material filling the holes in the tan bone is dark gray in color (with a couple spots with rust-colored staining), which contrasts with another Hell Creek sample in my collection with rust-colored infilling in almost-white bone. The latter specimen clearly hasn't changed over a period of years, whereas the former, if I'm correct, has changed a bit in the course of months.

[FranzBernhard]

@Troodon is the Hell Creek specialist! Thank you!

Franz Bernhard

[Troodon]

I've never run across it on bones where I've collected

[Oxytropidoceras]

16 hours ago, Maniraptora said:

Thanks for the helpful info! That's pretty frustrating that there's no way to prevent this. I guess a lot of specimens will eventually become "lost to science" via pyrite.

 

 

How about making a 3D scan of it and converting it into a digital model. Also, color images of the specimen can be applied to the digital model?

 

By the way, below are some papers about pyrite disease with links to their PDFs.

 

Tacker, R.C., 2020. A review of “pyrite disease” for paleontologists, with potential focused interventions. Palaeontologia Electronica, 23(3). open access

 

Becherini, F., Del Favero, L., Fornasiero, M., Guastoni, A. and Bernardi, A., 2018. Pyrite Decay of Large Fossils: The Case Study of the Hall of Palms in Padova, Italy. Minerals, 8(2), p.40. open access

 

Larkin, N.R., 2011. Pyrite Decay: cause and effect, prevention and cure. NatSCA News, 21, pp.35-43

 

Yours,

 

Paul H.

Edited January 14 by Oxytropidoceras
added papers

[Maniraptora]

5 hours ago, Troodon said:

I've never run across it on bones where I've collected

 

Well, that's encouraging! It can't be terribly common if you haven't run into it, with how much collecting I know you've done there.

 

3 hours ago, Oxytropidoceras said:

 

How about making a 3D scan of it and converting it into a digital model. Also, color images of the specimen can be applied to the digital model?

 

By the way, below are some papers about pyrite disease with links to their PDFs.

 

Tacker, R.C., 2020. A review of “pyrite disease” for paleontologists, with potential focused interventions. Palaeontologia Electronica, 23(3). open access

 

Becherini, F., Del Favero, L., Fornasiero, M., Guastoni, A. and Bernardi, A., 2018. Pyrite Decay of Large Fossils: The Case Study of the Hall of Palms in Padova, Italy. Minerals, 8(2), p.40. open access

 

Larkin, N.R., 2011. Pyrite Decay: cause and effect, prevention and cure. NatSCA News, 21, pp.35-43

 

Yours,

 

Paul H.

 

Looks like these will be really helpful papers! Thanks. And yeah, I hadn't thought about the 3D model approach. That definitely prevents the loss of a lot of data.