Delicate Mastodon tusk extractions, any tips?

[Cthulhu2]

Hey guys. My fossil group found a submerged mastodon tusk while hunting. It’s completely underwater and very delicate (it falls apart super easy). Any idea on how to extract such a delicate tusk? The thing falls apart in your hand, we could only salvage some chunks last trip. 
 

As for preserving what would you guys recommend so the dang thing doesn’t fall apart?

 

thanks!

[Bobby Rico]

@Ptychodus04 Kris is a wonder at preserving fragile specimens. 

[Ptychodus04]

This one sounds like a nightmare. How deep is the water you're dealing with? If it is shallow enough, you can build a berm with sandbags to stop the flow of water to it. Then, use a pump to remove the water from around the tusk. This will allow you to jacket the tusk in order to get it out as intact as possible.

 

I used a similar tactic to excavate the Pentanogmius fritschi holotype specimen. We dug a trench around the specimen and pied up the shale and mud to mage a berm to divert the creek from the specimen. This worked really well but we only had to deal with about 6" of water.

[hadrosauridae]

If its already coming apart in chunks, it may not be savable.  Any attempt will require some form of jacket and reinforcing to bring it up.  Fastest may be HD aluminum foil to hold the bits in place, then a wire mesh tray to bring it up and transport.  PLan on it still crumbling as it dries, but if you are careful you work your way from one end to the other gluing the bits of the 3D puzzle back together.

[fossilus]

I faced a similar situation last year.  Mine was mammoth, buried in mud. Unfortunately when it dried the mud was as hard or harder than the tusk.  I was able to salvage some chunks but that was all.

[Cthulhu2]

32 minutes ago, Ptychodus04 said:

This one sounds like a nightmare. How deep is the water you're dealing with? If it is shallow enough, you can build a berm with sandbags to stop the flow of water to it. Then, use a pump to remove the water from around the tusk. This will allow you to jacket the tusk in order to get it out as intact as possible.

 

I used a similar tactic to excavate the Pentanogmius fritschi holotype specimen. We dug a trench around the specimen and pied up the shale and mud to mage a berm to divert the creek from the specimen. This worked really well but we only had to deal with about 6" of water.

Its only 6inches of water thankfully, diverting may be a big task. I’ve never Jacketed some before too, where should I get started with that?

[jpc]

Tusks can be nasty.  They want to fall apart more than any other fossil I know of.   I have not collected a wet tusk, but I have done a few dry ones and even thense just wanted to fall apart as they dried.  A wet one will need to be dried very slowly.  Even if you do a paster jacket, you will have to leave some of it open so it can dry for a few months to a year or two, and it will most likely shrink.  The folks at the museum in Gainesville might have some pointers for you.  I bet they have collected a wet tusk or two.    

[Ptychodus04]

On 7/29/2021 at 4:15 PM, Cthulhu2 said:

Its only 6inches of water thankfully, diverting may be a big task. I’ve never Jacketed some before too, where should I get started with that?

I agree with @jpc talk to the museum.

 

Field jackets are easy. All you need is burlap, plaster, and water. Cover the tusk in aluminum foil or toilet paper. Cut the burlap into strips, mix plaster with creek water, lay the plaster soaked burlap over the tusk. Be sure to go more than half way around the tusk or it will fall out of the jacket when you lift it.

 

Make several layers. I would even add some thin boards for additional stability along the length of the jacket. Just all them between a couple layers of burlap. End it all with a heavy coat of plaster.

 

Once it dries, you should be able to flip over the tusk for transport. The worst part is going to be diverting the water. Our diversion tactic took an entire day to complete. Then, if you’re successful, you will have a nasty, crumbling, broken tusk at home and you can sit back and wonder what made you think it was a good idea to collect it…