General preparations for Niobrara Fm. field trip

[The Amateur Paleontologist]

Hey everyone  

Though it'll probably take place next summer, I'm already running through some preparations for my field trip to the Niobrara Chalk Fm. of western Kansas. Based on what I've heard from other collectors (and my own experiences in other sites), I drew up a list of stages I should go through for excavating and preparing any vertebrate material (especially fish) I might encounter..

 

 

1)   Surrounding matrix/overburden is brought down to expose the bone layer

 

2)   Shellac/Vinac/other consolidant is applied to the exposed surface

 

3)   Fossil is covered in plaster

 

4)   Plaster slab is removed and brought back home

 

5)   Removing the underlying matrix of the fossil

             ->Surface that has never been seen before

                        -Proceed with care

             ->Using picks/dental tools

 

6)   Consolidating the fossil by brushing it with polyvinyl acetate (PVA or Vinac) dissolved in Acetone (50:1 ratio – acetone being the 50 parts)

             ->Vinac gives a nice appearance to the bones

 

7)   Removing the excess rock on the sides and smoothening the chalk for aesthetical effect

 

 

Does this look good? If so, what should be changed? @KansasFossilHunter @Ramo @grokfish @MikeE @Xiphactinus @Castle Rock

 

Thanks for the help  

-Christian

 

 

P.S. Would any of the steps need to be changed in case I encounter reptile material?

[Castle Rock]

Looks fine to me! 

[Ramo]

It sounds so easy, reading it like tjat!!

Don't forget plenty of water, some thin strips of wood and burlap to strengthen the jacket, and hand lotion for your hands that will dry out from the plaster.  It wouldn't hurt to set up a simulation of some kind to practice on.  I'll post some pictures tomorrow of my biggest jacket ever that I did thus summer.  

[JimB88]

remember to put tinfoil or news paper between the fossil and the plaster so you dont damage anything!

[Xiphactinus]

1 hour ago, JimB88 said:

remember to put tinfoil or news paper between the fossil and the plaster so you dont damage anything!

For the chalk, I would NOT recommend this on a fish. You want the plaster to stick to the bones. Once you prep from the bottom, you will be left with bones stuck to plaster...keeping everything in position. If you put a release layer between the bones and plaster, everything will fall apart.

 

That's the tried and true method for hunting in the chalk that has worked since the 1800's.

[Xiphactinus]

Here's what a giant jacket looks like with bracing. (This is too big. Don't do this!)

 

[jpc]

And don't use shellac.  

 

Many of the fossils from out there are pretty big.  Be prepared for that if you have to fly home.  Big AND heavy.  

[The Amateur Paleontologist]

3 minutes ago, jpc said:

Many of the fossils from out there are pretty big. 

C'mon, jpc.. Do you really expect a Kansas chalk novice like me to actually discover some 4-foot-long Cimolichthys?  The best I'll probably find will be a few little fish vertebrae...

-Christian

[Xiphactinus]

7 minutes ago, The Amateur Paleontologist said:

C'mon, jpc.. Do you really expect a Kansas chalk novice like me to actually discover some 4-foot-long Cimolichthys?  The best I'll probably find will be a few little fish vertebrae...

-Christian

Honestly....It's fairly easy to find a fish over 3 feet. Even if you find a loose tail from a Xiphactinus, you're looking at a jacket that is easily 3 to 4 feet wide. That's one of the reasons the chalk is world famous. Most of the fossils are articulated. In most places, you find a vert here, a tooth there. In the Kansas chalk, a good percentage of the fossils are the entire critter, or at least a big section.

 

And yes, our first trip to the chalk, we found a 4-foot-long Cimolichthys!   We had no clue what we were doing, but did manage to get it home. Thank goodness we found a sheet of old plywood that had been dumped on the ranch. Slid the fish onto it like a platter. Rookies can and do find big stuff

[jpc]

The only thing I have found in the Niobrara is a Xiph skull in a concretion.  It is 30-40cm around and weighs much more than I would want to bring on a plane.  

[The Amateur Paleontologist]

1 hour ago, Xiphactinus said:

Honestly....It's fairly easy to find a fish over 3 feet.

Not sure whether to be pleased or not about that fact..  I mean sure, it'd be cool (in my opinion) to have a nice big Cimolichthys, but in terms of logistics/transport... 

@jpc Would sending a specimen (jacketed and consolidated of course) by airmail back to my country be a good idea, tho?

-Christian

[jpc]

2 minutes ago, The Amateur Paleontologist said:

Not sure whether to be pleased or not about that fact..  I mean sure, it'd be cool (in my opinion) to have a nice big Cimolichthys, but in terms of logistics/transport... 

@jpc Would sending a specimen (jacketed and consolidated of course) by airmail back to my country be a good idea, tho?

-Christian

It would be a great idea... but an expensive one.  I still have a large slab from Dotternhausen (Deutschland) with a crinoid stem in it living in my aunt and uncle's barn in Switzerland.  It had been there since 2011...  

[The Amateur Paleontologist]

@jpc then I guess I'll have to travel (very) lightly, and try to reduce as much as possible the mass of any block of chalk that I might consider bringing home... 

-Christian

[Xiphactinus]

I've not done it personally, but I do know of people that have used expanding foam spray as a lightweight jacket option. Build a form around the fossil with cardboard and then fill it with spray foam. In this case, you would NOT want the foam to contact the fossil.

[Castle Rock]

I have had a fair bit of experience collecting in the chalk myself and I think several of the statements made above are CLEARLY the exception and NOT the rule.  I have made MANY trips out there and found NOTHING but float.  Sure, it's good to be prepared but, honestly, let's keep expectations realistic. Just this year, I have made two trips up to western Kansas, one in May (during a relative drought period) and one in August (after some serious rainfall).  Nothing but float this year.  Yes I have had some really great years, but many more that were LEAN. Contrary to an earlier remark, MOST fossils up there are NOT "big".  Not trying to be a downer here, but I started collecting up there in 1962! Dave

[The Amateur Paleontologist]

@Castle Rock You know, I'd already be very pleased with just some 'float' material.

-Christian

 

P.S. what sort of float did you find?

[Castle Rock]

7 hours ago, The Amateur Paleontologist said:

what sort of float did you find?

I found several isolated teeth and some vertebrae, including a couple that were large enough (an inch across) that they really frustrated me, in that I could find nothing else of the remains.  I can only conclude that the remainder of the remains were scattered by scavengers. After having had a couple of EXCELLENT hunts over the last few years, it was a disappointment that something more consequential was not found. I had to be quick to remind myself that it takes a lot of average years to realize a great one!

[Ramo]

I said I would post a few photos of "jacketing" in the Niobrara.  Sorry it took so long.  I'm a little behind with my real job.

Here is a Cimolichthys I found after digging down to the "bone bed".  I had found the base of a skull eroding out of a bank.  The skull was gone.  I uncovered the bones, and found most of the verts in pretty good shape.  I mixed up some plaster, and poured it directly on the bones.  I went looking for other stuff and came back a couple hours later and flipped the jacket.  All the bones were stuck in the plaster,  some matrix also came up, but not a lot. I brought it home and cleaned off all the matrix leaving just the bone and plaster. 

Fast forward a year or two, and I found a Cimolichthys skull that would be the correct size for my cimo body, so I made a frame.  Placed them together, and made a composite.  Now it proudly hangs on the wall of my "museum"

[The Amateur Paleontologist]

@Ramo Neat specimen - thanks for showing! Just to know, how did you prepare it?

-Christian

[Ramo]

Here are some photos of my biggest jacket yet.  This was done earlier this summer.  I got ahold of Xfish, for some advice on large jackets, and he helped to advise me to not make it too big.  Unfortunately it ended up too big anyways!!

I found a part of an X-fish pectoral fin laying in a small gully.  I then found where it came from and started uncovering the overburden.  I found most of the skull, and a string of verts going back into the bank.  I glued the exposed bones, and covered it up since I had neither the time, nor the materials to get it out.  I uncovered back to a fault in the rock that was about 4 feet of fish exposed.  I thought that the rest of the fish would be on back in the bank.

I returned 3 days later with my son, and a bunch of plaster.  We dug back into the bank and found that there was no more.  We did find part of an upper jaw in the washed out area when we were digging the trench.   No lower jaws were found.   Some of the bones were disarticulated, and it appears that this fish must have been bitten in half.  The exposed bone bed was 2' X 4'.  Too big for one jacket, and almost too small to "split" into to, so of course, we tried it with one.  I used a chainsaw to trench around the slab.  This was the first time I ever tried this, and I loved it.  It worked great, and most importantly it did not jar the slab like chopping around it with a pick would.  The slab was a little crumbly, so I was worried it would all crumble.  We drove some long screwdrivers under the jacket in a few spots to try and loosen it.  We then went to flip it.  It was HEAVY!!!  Almost all the chalk inside fell out despite our best efforts, and I thought all was lost.  After we got it flipped we saw that all the bones were safely locked in the plaster.  If the chalk would have stayed in we would have never been able to lift it anyways!  The two of us struggled  and took 3 or 4 breaks, to carry it the 50 yards over to the truck and were able to get it home.  I was able to do some work cleaning, and gluing the bones, but it isn't done yet.  Hopefully this winter I will get it completed.  In the final picture, the ditch that washed out and exposed the fossil would have been parallel to where the jaws were.  It claimed the jaws, teeth, and part of the pectoral fins.  I would guess sharks claimed the back end.  I'm happy with the middle!!!  It has been a ton of work, and there is still quite a bit to do, but its fun!!   (Sorry the pictures are sideways, I thought I fixed them, I don't know how the move them.)

[The Amateur Paleontologist]

@Ramo That's quite an amazing specimen  thanks for sharing this - part of me is actually hoping that I won't find something like that (given my lack of experience...)

-Christian.

[Xiphactinus]

Nice job documenting the process @Ramo!  Nice fish too!

[Ramo]

Thanks again for your advice xiphactinus,  even though I didn't take it when it came to jacket size!