How do I preserve/ prep shale fossils?

[Joe Salande]

Greetings guys/gals.

 

I have recently received some leaf imprints in shale stone.

These are from the Minkin site in Northern Alabama.

These are from the Carboniferous period and are imbedded in shale rock. That's a bit soft..

I am asking how would you guys suggest that I clean up and preserve them.

That is with the lease amount of equipment. So basic wash technique and 

would you suggest using paranoid on these things?

Any thoughts would be greatly appreciated.

Thanks,

Joe

 

[Thomas.Dodson]

14 minutes ago, Joe Salande said:

would you suggest using paranoid on these things?

I'm always paranoid about fossil preparation.

 

These seem to be in pretty clean shape as is. Is there anything in particular you wanted to try and reveal? If there's uncovered leaves the pick and scrape method with some needles would work best and shouldn't be too hard since they're soft. I'd be careful washing them too much. The water might damage any carbon film depending on the preservation.

 

I don't think you will need to use paraloid on these. They look pretty sound to me but pictures aren't the best judge of this. Some people coat their plant fossils regardless with PVA or paraloid. I prefer to only do so if I have reasonable fear of disintegration or degradation. Maybe others more familiar with this specific site will weigh in.

[Joe Salande]

Thanks Tomas.

I'm a bit nervous about doing to much also. But I want to be sure to do at least the best minimal things. What I posted is pretty representative of how they 

look currently. It was quite the chore to collect these

and would hate to have Not done a simple procedure.

I was just thinking a little paranoid may give them a little shine, but I don't want to do that if it would injure them.

 

Anyhow, thanks for the recommendation.

Joe

[FranzBernhard]

2 hours ago, Joe Salande said:

I was just thinking a little paranoid may give them a little shine, but I don't want to do that if it would injure them.

Try it with the poorest specimen and see, if you like the resulting look. Sure, paraloidia can be removed, but the look of the specimen could have been already permanently changed.

 

6 hours ago, Thomas.Dodson said:

Maybe others more familiar with this specific site will weigh in.

Yeah, look at the "history" of specimens from this specific site.

 

6 hours ago, Thomas.Dodson said:

The water might damage any carbon film depending on the preservation.

That´s also my greatest fear. Matrix looks quite stable (the matrix is already in the diagenetic stage of at least bituminous coal, maybe even anthracite?); carbon films could flake off, if specimen dries out and wetted again, though.

 

Franz Bernhard

[Wrangellian]

Is there an autocorrect feature somewhere that is changing 'paraloid' to 'paranoid'?

I concur with the others.. I'd be paranoid about using Paraloid or any other coating on these. For the most part fossils don't need coating, unless they're going to be handled repeatedly by children..... and don't need prepping unless there are parts of the fossil(s) that are covered by matrix, but I don't see anything like that here. I would not wash, either, if a simple brushing will remove dust/dirt.

[Sjfriend]

Absolutely do not use water to wash if any carbon film left as it will lift it off. Also, if shale is soft the water could smear it.

 

As for using a paraloid or PVA, if fossil is stable no need. But, on a lot of my plant fossils the carbon starts to dry out and flake off so I use VINAC to preserve them. Not all get treated but those that either the carbon film is weak or the matrix itself is needs to be stabilized. 

[cngodles]

Once you add the paraloid, it will have a permanent wet look. Not recommended.

 

The only prep I'll do with shale plant fossils it to use a granite cutting wheel grinder to carefully cut off excess if I can. An example here, where there was no way I was keeping this Calamites specimen on the huge 3 foot by 3 foot slab it was on. To note though, a lot will be covered with dust so it may not be worth it for a carbon film plant specimen.

 

[LabRatKing]

I have destroyed more amazing fossil detail with paraloid and other methods than I care to admit. Please consider proper storage over chemical treatment.

 

a bit of mineral oil goes a long way and eliminates chemistry risk.

 

my two bits.