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Preserving Leaves


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#1 ashcraft

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Posted 23 October 2009 - 08:35 AM

I have found a deposit of pleistocene material, 20,000 years old or so. It appears to be a flood deposit, full of leaves and wood, which are encased in a sticky clay.

I split a piece of the clay and found a beautiful whole leaf, which I set to the side. A few minutes later, Bill wandered by, and I picked it up to show him. Imagine my consternation when it was gone! I split another piece, finding a part of a leaf, beautiful and brown. I then watched it, in 2.5 minutes it turned from a brown leaf to ash.

My question is, how can you preserve such a specimen? The clay is wet, so spray on coatings will cloud up. Is there a water-soluble spray on coating? Any other suggestions?

Brent Ashcraft
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#2 tracer

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Posted 23 October 2009 - 09:15 AM

i'd try cyanoacrylate (super glue), and i'd separately try pva/water-thinned emulsion (like elmer's). if neither works, then i don't know what would, other than photographing them.

if the stuff is that fragile, it might require trying to "fume" or "mist" the fossils with the consolidant - a dicey proposition.

good luck with it.
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#3 jkfoam

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Posted 23 October 2009 - 09:16 AM

Brent,

You might try diluting Elmers glue with water and using that to preserve those leaf prints. I would try it on a scrap piece first to see if it will work.

JKFoam
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#4 ebrocklds

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Posted 23 October 2009 - 09:19 AM

cyanoacrylates will fog as well. i would suggest an elmers solution like tracer mentioned. you can also try a matte finish clear spray paint somebrands will fog but others won't the next problem you are going to have is the matrix crumbling. the elmers should help with that.

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#5 tracer

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Posted 23 October 2009 - 09:31 AM

cyanoacrylates will fog as well. i would suggest an elmers solution like tracer mentioned. you can also try a matte finish clear spray paint somebrands will fog but others won't the next problem you are going to have is the matrix crumbling. the elmers should help with that.

Brock


thanks for correcting me on the cyanoacrylates, brock. i had remembered that they set up faster in the presence of moisture, but forgotten that they fog.
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#6 Auspex

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Posted 23 October 2009 - 10:04 AM

Try Future Floor Polish to fix the organic film in place; you are still left with what clay does when it dries out, though.

"There has been an alarming increase in the number of things I know nothing about."
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#7 ashcraft

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Posted 23 October 2009 - 10:23 AM

Thanks all, so far good suggestions. I had considered elmer's wash. Floor polish is something I have no experience with. How would you apply? Brush? Spray bottle?
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#8 Xiphactinus

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Posted 23 October 2009 - 10:32 AM

Ashcraft -
I've been working with similar stuff from Coldwater Creek. IF the leaves can handle it, immerse the clay with the fossils in acetone for several days. This should drive out the water without drying the leaves. Replace the pure acetone with an acetone/vinac solution and continue soaking. After a few days, remove and allow to dry. The vinac should keep the leaves from drying out and dizzolving, and should keep the clay from shrinking too much.

Edit - take aluminum foil with you in the field and tightly wrap the fossil immediately to get it home w/o drying.

Edited by Xiphactinus, 23 October 2009 - 10:33 AM.


#9 ashcraft

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Posted 23 October 2009 - 10:54 AM

x-man,

Thanks, great suggestion.

Brent Ashcraft
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#10 ashcraft

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Posted 23 October 2009 - 12:26 PM

Ashcraft -
I've been working with similar stuff from Coldwater Creek. IF the leaves can handle it, immerse the clay with the fossils in acetone for several days. This should drive out the water without drying the leaves. Replace the pure acetone with an acetone/vinac solution and continue soaking. After a few days, remove and allow to dry. The vinac should keep the leaves from drying out and dizzolving, and should keep the clay from shrinking too much.

Edit - take aluminum foil with you in the field and tightly wrap the fossil immediately to get it home w/o drying.



By the way, what kind of leaves are you finding? I know Bruce has told me the Coldwater Creek deposit is around 30,000 years old, based on radio carbon dating. I think the deposit I am working on is somewhat younger, 20,000 years or so. I have not found any boreal remains, all hardwood, with butternuts, which are not common down here now. I think the forest supposedly changed over around 20,000 years ago or so.

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#11 tracer

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Posted 24 October 2009 - 05:42 AM

i thought of two more points, based on what x-man and auspex said. first, if the acetone doesn't work, you could try ethanol. ethanol does mix with water, though, so it's a different concept. i've taken water-soaked fossils through successive "baths" of progressively greater concentrations of ethanol up until they're in 100% ethanol. i did this in order to prevent shrinkage or cracking during the drying process. at any rate, something else that could be tried.

as far as the floor polish goes, i believe it may now be called "pledge with future shine". it is also apparently used a lot by modelers and other hobbyists and is available semi-worldwide under different names. the msds sheet on it indicated it's a water-based acrylic with small amounts of a couple of big-word ingredients that might be surfactants and/or preservatives or something - i wasn't in big-word-lookup-mode at the moment. apparently the polymer hardens very glossy, so modelers sometimes add a "flattening" component to dull the finish.

i've never used the floor polish, but it seems so widely used that it might be a pretty good thing to experiment with. sounds like it could be thinned if needed, and that the fossils could be dunked in it, since it's water-based.
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#12 Xiphactinus

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Posted 24 October 2009 - 08:23 AM

By the way, what kind of leaves are you finding? I know Bruce has told me the Coldwater Creek deposit is around 30,000 years old, based on radio carbon dating. I think the deposit I am working on is somewhat younger, 20,000 years or so. I have not found any boreal remains, all hardwood, with butternuts, which are not common down here now. I think the forest supposedly changed over around 20,000 years ago or so.

Brent Ashcraft

I'm not sure....I find fragments and want to work on finding more complete leaves to study the ecosystem. I've been finding a lot of spruce cones and wood. The coolest thing is I'm finding wood that was chewed by beavers 30-40,000 years ago! I've been trying to perfect how to preserve the chewed wood. The system I described above seems to work well with minimal shrinking and distortion. Once we get some dry time and the creek goes down (Oct. has had 4x the normal amount of rain - a new record dammit) I'm working hard to find wood chewed by a giant beaver! As far as I know, that has never been found. We've found the teeth/bones, so the chewed wood should be there.

#13 ashcraft

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Posted 24 October 2009 - 10:01 PM

I'm not sure....I find fragments and want to work on finding more complete leaves to study the ecosystem. I've been finding a lot of spruce cones and wood. The coolest thing is I'm finding wood that was chewed by beavers 30-40,000 years ago! I've been trying to perfect how to preserve the chewed wood. The system I described above seems to work well with minimal shrinking and distortion. Once we get some dry time and the creek goes down (Oct. has had 4x the normal amount of rain - a new record dammit) I'm working hard to find wood chewed by a giant beaver! As far as I know, that has never been found. We've found the teeth/bones, so the chewed wood should be there.


Rich H with the EMSP thinks he has a piece. He has it preserved in a jar with water and iodine. My two pieces of spruce from this summer are doing fine after soaking for two weeks in 50/50 water elmers

Edited by ashcraft, 24 October 2009 - 10:12 PM.

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#14 Auspex

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Posted 25 October 2009 - 03:34 PM

...I'm working hard to find wood chewed by a giant beaver! As far as I know, that has never been found. We've found the teeth/bones, so the chewed wood should be there.

Check this out (forwarded from another thread, started by
Angus Stydens):
http://dsc.discovery...avers-wood.html

"There has been an alarming increase in the number of things I know nothing about."
-Ashleigh Ellwood Brilliant




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