Jump to content

Lyme Regis plesiosaur propodial with pyrite disease - how to treat


pachy-pleuro-whatnot-odon

Recommended Posts

pachy-pleuro-whatnot-odon

Hi all,

A couple of years ago I acquired a lovely pair of plesiosaur propodial bones from Lyme Regis. It was a matched pair of both humerus and femur. Today, when I was looking to make space in my cabinet for a new acquisition I had made, I discovered some odd dust next to the humerus that, on inspection and to my horror turned out to be pyrite bloom! I immediately removed the specimen from the cabinet, checked the other podial and nearby fossils, and used a tooth brush to brush of the most direct traces of pyrite decay. But the question is: what now? How do I ensure the propodial's preservation, and make it safe for display again. Should I store affected piece in an open or closed container? I suspect the latter, together with silica beads to consume any excess moisture might be best right now. But how do I get to the point where I can take it out again? Any suggestions are welcome.

 

From my own thread on this topic I know of the existence of pyrite stopper, which sounds ideal for this situation. But I've also been warned that this is quite a hazardous solution and am therefore afraid of trying this out myself. So, part of the question would be whether someone offers pyrite treatment as a service, of knows of someone who does.

 

Thanks in advance for your help!

 

1467886249_LymeRegisplesiosaurpropodialwithpyritedisease01.thumb.jpg.ee7d4f94dfe5452a95417f1771e95f64.jpg1019085578_LymeRegisplesiosaurpropodialwithpyritedisease02.thumb.jpg.b59f7cb3299fd2d43c34029ea512e88c.jpg798077860_LymeRegisplesiosaurpropodialwithpyritedisease03.thumb.jpg.28dfe5cd4d4e29af321fdf8c90c5feba.jpg1906220976_LymeRegisplesiosaurpropodialwithpyritedisease04.thumb.jpg.1cfa2c42e93e344342829b7af7c5ee72.jpg

 

2134981883_LymeRegisplesiosaurpropodialwithpyritedisease05.thumb.jpg.6385a24a4e25174f4b46d905ada154f7.jpg1357447650_LymeRegisplesiosaurpropodialwithpyritedisease06.thumb.jpg.2f7b2e7bf1d02580137d7518e504947d.jpg

 

1093418834_LymeRegisplesiosaurpropodialwithpyritedisease07.jpg.be917db03fd9585c58264871703df61f.jpg628874819_LymeRegisplesiosaurpropodialwithpyritedisease08.thumb.jpg.53d3f36338d193216d73aa16cda78a2e.jpg

 

1826144622_LymeRegisplesiosaurpropodialwithpyritedisease09.thumb.jpg.1d02eaed573a3975d979af549ba61566.jpg1040826077_LymeRegisplesiosaurpropodialwithpyritedisease10.thumb.jpg.b48c1976a78b96ab30000894b202b154.jpg

 

 

@Ptychodus04 @DanJeavs @paulgdls @RuMert and others

 

 

Edited by pachy-pleuro-whatnot-odon
Link to post
Share on other sites
Manticocerasman

try to clean it out as much as possible and then seal it with paraloid B72 . I can't guarantee it will work, but that's what I would do.

 

once the decay has started there is not much els you can do I think.

Edited by Manticocerasman
  • Thank You 1
Link to post
Share on other sites
pachy-pleuro-whatnot-odon

Apart from the pyrite stopper, I've also heard of people just blasting or prepping the decay product of and then indeed sealing it, to prevent further decay. Since I bought this piece from a befriended seller three years ago, and this UK-based seller also provides preparation services, I decided to also get in touch with them to see if they might offer services to help stabalize the decay. I'm still awaiting a response. But with the Oxford Show taking place this weekend, it may be a while before I get an answer. There a couple of other UK-based preparators that I might give a try in case the original seller can't help me. But as I can't blast the spot myself (I lack the equipment) and don't want to dig a hole in the bone, getting someone from the UK with experience in Lyme Regis material involved doesn't seem like a bad idea at this point... Especially since the propodials are a matching pair, it would be a real shame to loose one of them. Moreover, the morphology of the specimen is relatively unique to the early stages of the Jurassic, so it's the only specimen I've got and not easy to replace...

Link to post
Share on other sites

Pyrite decay is a slow process. It won’t hurt the specimen to sit for a few weeks until prep can be done as long as you isolate it from the other fossils. The sulphuric acid produced by the decay is pretty indiscriminate.

 

 

  • I found this Informative 1
Link to post
Share on other sites
pachy-pleuro-whatnot-odon
43 minutes ago, Ptychodus04 said:

Pyrite decay is a slow process. It won’t hurt the specimen to sit for a few weeks until prep can be done as long as you isolate it from the other fossils. The sulphuric acid produced by the decay is pretty indiscriminate.

 

Thanks, Kris! Good to know, as I do hope to find someone who can help me with this and that may take some time, especially if I need to have the specimen shipped... I've already isolated the specimen (though haven't added silica gel yet, as I don't seem to have any packs lying around! :o Hopefully I can pick up some nearby or order some online. I've also cleaned the spot with a moistened kitchen towel. Hopefully that'll be enough to clean up any traces of the sulphuric acid and make the shelf save for storing other fossils on again (the shelf is laminated)...

 

Other than that, any recommendations on how to deal with or treat this kind of affliction? I mean, I might not need to act immediately, but I will need to act eventually...

Edited by pachy-pleuro-whatnot-odon
Link to post
Share on other sites

A little pyrite dust is not a verdict:D Lots of specimens are for years exposed to different weather conditions and get afterwards covered by grayish dust but nothing happens to them. I have many pyritized specimens but didn't lost anything apart from 2-3 vertebrae sets which were already in poor condition

  • I found this Informative 1
Link to post
Share on other sites
pachy-pleuro-whatnot-odon
13 minutes ago, RuMert said:

A little pyrite dust is not a verdict:D Lots of specimens are for years exposed to different weather conditions and get afterwards covered by grayish dust but nothing happens to them. I have many pyritized specimens but didn't lost anything apart from 2-3 vertebrae sets which were already in poor condition

 

While true and something a lot of museums with collections from pyrite-rich deposits work based upon, such external symptoms of decay belie the decay going on inside such pieces. Agreeably, the decay may go very slow, but it's likely to still take place and pose a risk to other specimens. That's why museums continuously remove and treat such visible traces of pyrite disease...

Link to post
Share on other sites

For example, a pyritized ammo I found a year ago. It was exposed to everything and already covered with gray dust. Guess what? Nothing happened to it

IMG20201011132621.jpg

  • I found this Informative 1
Link to post
Share on other sites
pachy-pleuro-whatnot-odon
1 minute ago, RuMert said:

For example, a pyritized ammo I found a year ago. It was exposed to everything and already covered with gray dust. Guess what? Nothing happened to it

IMG20201011132621.jpg

 

I guess, though, there might be a difference between a specimen that had already reached a stable state of decay, versus one that has just started showing signs of it, after having been stable for three years or more...

Link to post
Share on other sites

Maybe:) With valuable specimens I'd 1st heated them on a stove (kills bacteria), then covered with Paraloid or varnish. A popular method here is boiling in paraffin, I've never practiced it

  • I found this Informative 1
Link to post
Share on other sites

Neutralization of the sulphuric acid and low relative humidity are the most important factors. Coating / Sealing with Polyvinyl acetate, Shellac or Polybutyl Methacrylate (Paraloid) is not effective and not recommended anymore.Pyrite Oxidation Review and Prevention Practices.pdf

Edited by oilshale
  • I found this Informative 1
  • I Agree 1
Link to post
Share on other sites
pachy-pleuro-whatnot-odon
6 minutes ago, oilshale said:

Neutralization of the sulphuric acid and low relative humidity are the most important factors. Coating / Sealing with Polyvinyl acetate, Shellac or Polybutyl Methacrylate (Paraloid) is not effective and not recommended anymore.Pyrite Oxidation Review and Prevention Practices.pdf

 

That's what I've heard as well... As I understand it, there's no guarantee of an airtight seal, you might lock in humidity and/or sulfuric acid and either continue or exacerbate the decay, and complicate further future treatment.

 

12 minutes ago, RuMert said:

With valuable specimens I'd 1st heated them on a stove (kills bacteria), then covered with Paraloid or varnish. A popular method here is boiling in paraffin, I've never practiced it

 

I recently got a batch of fossils that had been treated with paraffin fifteen years ago. I can't say I was overwhelmed by the results. The fossils were dark with little detail visible, and felt brittle to the touch. Obviously the paraffin was holding the specimens together as a surface coating, but hadn't had any penetration. So I removed the paraffin (as best I could), heated the specimens up, and dunked them in Paraloid. The result is that a lot more detail is visible now, and the fossils no longer feel as brittle...

 

Your suggestion of heating the specimen in an oven might be worth a try, though :b_idea:

Link to post
Share on other sites
21 hours ago, Manticocerasman said:

try to clean it out as much as possible and then seal it with paraloid B72 . I can't guarantee it will work, but that's what I would do.

 

once the decay has started there is not much els you can do I think.

 

I agree. Clean it by grinding the bloom off to a smooth surface (this gives minimum surface area), wipe with a rag soaked in acetone to remove the dust, then apply a couple of layers of thick paraloid. This has worked on a number of my fossils where the pyrite decay isn't too bad. Often the surface layers are the worst affected and once they are removed (which can take repeated removal over a number of years) the fossil is stable. 

 

all the best

 

Paul

 

  • Thank You 1
Link to post
Share on other sites
pachy-pleuro-whatnot-odon
49 minutes ago, paulgdls said:

 

I agree. Clean it by grinding the bloom off to a smooth surface (this gives minimum surface area), wipe with a rag soaked in acetone to remove the dust, then apply a couple of layers of thick paraloid. This has worked on a number of my fossils where the pyrite decay isn't too bad. Often the surface layers are the worst affected and once they are removed (which can take repeated removal over a number of years) the fossil is stable. 

 

all the best

 

Paul

 

Thanks, Paul! Will give this a try!

  • I found this Informative 1
Link to post
Share on other sites
pachy-pleuro-whatnot-odon

Just read that Paraloid B-67 might be better as a sealant after removal of the bloom, for its hydrophobic properties, but that it does tend to turn yellow with exposure to sunlight/UV. Anybody have any experience with this product? @Harry Pristis may be?

Link to post
Share on other sites

Sorry, I don't know of any simple way to stop pyrite disease.

  • Thank You 1
Link to post
Share on other sites
pachy-pleuro-whatnot-odon

Okay, so at least I've now got my packs of silica gel, which, together with the closed container and having brushed away most of the surface bloom should buy me some time, at least, while I figure out what exactly to do... Using a pyrite stopper may still be on the table after having received a link to this blog-post. Haven't read it yet, but it looks both informative and hope-giving.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...