Mazon Creek- Freeze / Thaw Results

[Nimravis]

I have not posted anything recently, but I thought that I would do a quick one. Here are the results of a number of freeze / thaw cycles of some of my Mazon Creek concretions.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

All Jellyfish here and above.

 

 

I will post more as they pop.

[Fossildude19]

Some really nice fossils popped in this batch, Ralph!

Thanks for posting them!
I always enjoy seeing your finds.

[Nimravis]

9 minutes ago, Fossildude19 said:

Some really nice fossils popped in this batch, Ralph!

Thanks for posting them!
I always enjoy seeing your finds.

Thanks- I just had four more Essexella’s come out. I like them a lot, but I want different things. I am freeze / thawing several hundred. Hopefully they keep opening, some have gone through several cycles.

[stats]

Very nice ones!  Love the Rhacophyllum!

 

Cheers,

Rich

 

[Jaybot]

Nice!  Great results, thanks for sharing!  Mazon creek concs are pretty interesting.

[Denis Arcand]

Really nice fossiles 

 

Can you explained the  freeze / thaw cycles

[Nimravis]

1 hour ago, Denis Arcand said:

Really nice fossiles 

 

Can you explained the  freeze / thaw cycles

With Mazon Creek concretions there are two ways to open them to see if there is a fossil inside. The easiest way is to whack them with a hammer, but with this process you can damage the fossil. I have a large thread on the Forum called “Sometimes You Have To Whack It”, check it out sometime and you can see what I found and what got damaged. The other way to open them is the preferred “Freeze / Thaw” method. The way that it accomplished is by placing the concretions in a bucket or other container and filling it with water. You leave the concretions in there so the water can soak into micro cracks that might be in the area of the plain line of where the fossil is sitting in the concretion. The vast majority of the fossil bearing concretions have the fossil almost in the center of the concretion (Width and height) as with this Essexella asherae jellyfish that opened last night:

 

 

 

As you can see from the pics, the plain line was found in the center of the concretion where it cracked and the fossil itself is orientated in the center of the concretion. But this is not always the case, as with this leech, it plain line was way off center, though the fossil was almost center on the two halves.

 

 

 

Once you soaked the fossils in the bucket for about a day, you place the bucket, with the water and concretions into the freezer and let it freeze. All collectors vary on the time that they let them freeze, but I leave them in there for about 36 hours and then take the bucket out and let it thaw. Once thawed, I dumped the water and lay the concretions out so they can dry. Some may pop open at this time, others I lightly tap with a hammer to see if they will open. When I am done with that, I start the process over and keep repeating. It is very time consuming, but better than the hammer method. The reason I use the hammer method in my other post was because I had over 105 gallon buckets full of concretions that I needed to go through. Trying to freestyle those would probably take 1 million years lol.

 

Here is a picture of two large containers that I am thawing out right now. They probably contain about 200 concretions. If I am lucky, maybe five concretions will open up.

 

 

and lastly, here is a picture of a bucket that contains 300 concretions that is soaking and waiting to be placed into the freezer. On this bucket, I decided to count how many concretions fit inside it so I can check the ratio of what’s opening.

 

 

I hope this answers your question.

[Nimravis]

Here are some Essexella asherae jellyfish that opened last night.

 

[Yoda]

@Nimravis

Fantastic fossils 

[Denis Arcand]

2 hours ago, Nimravis said:

With Mazon Creek concretions there are two ways to open them to see if there is a fossil inside. The easiest way is to whack them with a hammer, but with this process you can damage the fossil. I have a large thread on the Forum called “Sometimes You Have To Whack It”, check it out sometime and you can see what I found and what got damaged. The other way to open them is the preferred “Freeze / Thaw” method. The way that it accomplished is by placing the concretions in a bucket or other container and filling it with water. You leave the concretions in there so the water can soak into micro cracks that might be in the area of the plain line of where the fossil is sitting in the concretion. The vast majority of the fossil bearing concretions have the fossil almost in the center of the concretion (Width and height) as with this Essexella asherae jellyfish that opened last night:

 

 

 

As you can see from the pics, the plain line was found in the center of the concretion where it cracked and the fossil itself is orientated in the center of the concretion. But this is not always the case, as with this leech, it plain line was way off center, though the fossil was almost center on the two halves.

 

 

 

Once you soaked the fossils in the bucket for about a day, you place the bucket, with the water and concretions into the freezer and let it freeze. All collectors vary on the time that they let them freeze, but I leave them in there for about 36 hours and then take the bucket out and let it thaw. Once thawed, I dumped the water and lay the concretions out so they can dry. Some may pop open at this time, others I lightly tap with a hammer to see if they will open. When I am done with that, I start the process over and keep repeating. It is very time consuming, but better than the hammer method. The reason I use the hammer method in my other post was because I had over 105 gallon buckets full of concretions that I needed to go through. Trying to freestyle those would probably take 1 million years lol.

 

Here is a picture of two large containers that I am thawing out right now. They probably contain about 200 concretions. If I am lucky, maybe five concretions will open up.

 

 

and lastly, here is a picture of a bucket that contains 300 concretions that is soaking and waiting to be placed into the freezer. On this bucket, I decided to count how many concretions fit inside it so I can check the ratio of what’s opening.

 

 

I hope this answers your question.

 

Thanks for the explanation. I understand that only a small proportion usually open. How many times do you repeat the process before resorting to a hammer?

 

I ask all these questions because I have already tried freeze-thaw cycling processes on two shale slabs without much success. I did not know that others were doing it, I thought of it from my observation of nature. 

[Nimravis]

1 hour ago, Denis Arcand said:

 

Thanks for the explanation. I understand that only a small proportion usually open. How many times do you repeat the process before resorting to a hammer?

 

I ask all these questions because I have already tried freeze-thaw cycling processes on two shale slabs without much success. I did not know that others were doing it, I thought of it from my observation of nature. 

With the specific concretions that I have currently I will not resort to a hammer on them. I will continue the freeze thaw process until they open or disintegrate. These concretions were collected in the late 1970s and early 1980s from pit 11, so I am expecting to hopefully find a few nice things. With the specific concretions that I have currently I will not resort to a hammer on them. I will continue the freeze thaw process until they open or disintegrate. 

Edited November 23 by Nimravis

[Sjfriend]

Very cool pieces. Love the 2nd shrimp! Amazing to have that many from so long ago. Should keep you busy for a bit.

[Moth.11]

Love the shrimps

[Nimravis]

Here is a nice one that opened today, a 2-fer.

 

Myalinella meeki and a Cyclus americanus.

 

 

[FossilMo]

On 11/23/2024 at 1:02 PM, Nimravis said:

With the specific concretions that I have currently I will not resort to a hammer on them. I will continue the freeze thaw process until they open or disintegrate. These concretions were collected in the late 1970s and early 1980s from pit 11, so I am expecting to hopefully find a few nice things. With the specific concretions that I have currently I will not resort to a hammer on them. I will continue the freeze thaw process until they open or disintegrate. 

Wow so if I’m understanding this correctly, these concretions have taken ~40 years of continuous freeze/thaws to open?

[Nimravis]

1 hour ago, FossilMo said:

Wow so if I’m understanding this correctly, these concretions have taken ~40 years of continuous freeze/thaws to open?

No- they were collected that long ago- the Freeze / Thaw has just started.

[Nimravis]

Here are a few more from today, Essexella asherae jellyfish.

 

 

A small, possibly smashed Myalinella meeki.

 

[Nimravis]

Only two pieces popped today-

 

Mazonomya mazonensis-

 

 

A weak Pecopteris-

 

 

 

[Nimravis]

A couple from today- 2 weak Pecopteris and a nice coprolite.

 

 

 

 

 

[Nimravis]

Found a partial shrimp molt and Essexella asherae opened today, I will check more concretions later and see if anything else pops.

 

[Kohler Palaeontology]

Those jellyfish are very cool!! You don't hear of them in the fossil record that much.

[Nimravis]

I just did a quick check on some concretions that dried out after thawing and another Essexella asherae jellyfish popped as well as Belotelson magister shrimp. Not exactly what I am looking for, but it is something. This is a very long process to go through.

 

[Nimravis]

These are from today.

 

Annularia inflata

 

 

 

 

 

Macroneuropteris macrophylla

 

 

 

 

 

Shrimp

 

[Nimravis]

Today I went through about 110 concretions. 4 were duds and contained nothing, 3 had something in them. The remaining 107 are soaking again and will be frozen.

 

Here is what came out-

 

Possible trail - I do not believe it is an Acorn worm.

 

Essexella asherae-

 

 

Misc. Plant material-

 

[Nimravis]

I had some pop from a small bucket today, but nothing special.

 

A portion of what would have been a larger worm.

 

 

Another poorly preserved worm.

 

 

Mazonomya mazonensis 

 

 

A poorly preserved Neuropteris.

 

 

A cute Annularia-I could not find the positive portion of this tiny piece.

 

 

2- Essexella asherae 

 

 

2 pieces of coprolite.

 

 

 

 

And this last piece is just a poorly preserved piece of flora.

 

 

Hopefully tomorrow brings something nice- they are there, they just need to open.