4/2 &4/7 Pit 11 Mazon Creek

[Patrick K.]

Hi All! 
 

 I had the chance to head out last Sunday with my kid and again for a few hours yesterday solo - both times we came back with very heavy backpacks. It’s not easy collecting, but neither of us mind the army crawl in the underbrush. We’re still learning what to take and what to leave - just my 3rd and 4th trip there (thanks to fellow member and friend tom_mo for showing us the ropes and getting me addicted!!) We look for the small water created gully’s in the steep hills, lots of these have been collected over the years but just as many have not it seems. Or maybe the good collectors have just left all the big Essexella and midsized open concretions! Ha   It’s so exciting when we find a vein that has loads of nodules  - very addicting! I do use a hand held 15$ Home Depot hoe/cultivator to disturb the surface and move moss and leaves, and sturdy gloves to sift through the piles - it really helps. Still have to clean and prep the open ones from yesterday and start soaking these for freeze/thaw - but here’s some pics of the trove from each trip!

I’m going to start a separate thread with some questions I have for the long time Mazon Creek collectors - hope you have some time to help a newbie out!

 

 

Thanks for stopping by! 
Patrick 

 

[Mark Kmiecik]

Hell yeah! Nice haul. You'll have some great specimens when the freeze/thaw is done. Let them soak for at least a week before you start freezing; at least two weeks for the larger ones. Otherwise you'll only be peeling the outer layers. Post photos of the ones you found already open while we wait for the rest to open up.

[Patrick K.]

Thanks Mark - I’ve read lots of mazon creek threads that you’ve replied or started and definitely appreciate the info I’ve learned from them. I’ve started the soak on the 4/2 batch, they have a week in and I’ll wait another week on them all. I’ll get the open ones from 4/7 cleaned up and post anything besides Essexella that I find. I have a lot of these already - thinking of donating them to the esconi show next year as a door handout for kids. 
 

 

[Mark Kmiecik]

2 hours ago, Patrick K. said:

anything besides Essexella that I find. I have a lot of these already - thinking of donating them to the esconi show next year as a door handout for kids. 

 

Hold on to your Essexella. There have been recent developments as far as ID is concerned. There may be more than one taxon involved.

[Patrick K.]

This rather large and promisingly shaped concretion formed a seam in the last freeze/thaw, the first one ever of my collected ones to do so also. I feel like a 9 year old on Christmas Eve right now….it’s rather ridiculous! 

 

The separation is only partial still, although I can get it to flex open with the slightest separation pressure. I should prob just continue the freeze/thaw until it decides to show its face right?

[Phevo]

1 hour ago, Patrick K. said:

The separation is only partial still, although I can get it to flex open with the slightest separation pressure. I should prob just continue the freeze/thaw until it decides to show its face right?

 

I would, but I haven't used the freeze/thaw method personally

[Mark Kmiecik]

6 hours ago, Patrick K. said:

This rather large and promisingly shaped concretion formed a seam in the last freeze/thaw, the first one ever of my collected ones to do so also. I feel like a 9 year old on Christmas Eve right now….it’s rather ridiculous! 

 

The separation is only partial still, although I can get it to flex open with the slightest separation pressure. I should prob just continue the freeze/thaw until it decides to show its face right?

 

At this point you let them dry. Once dried you can tap lightly around the edges with a hammer and it will pop open easily. You don't have to wait until it's dry, but you take a slight chance that small parts may stick to the wrong half. I used to just let running water from the faucet hit the crack and force the two halves apart. Pick your poison -- this one is ready to open! 

[Patrick K.]

Grrr - it was just the outer shell. The next layer has no cracks. Sorry for the false alarm! 

 

I sure hope this isn't just going to peel off layers until nothing is left! 

[Mark Kmiecik]

35 minutes ago, Patrick K. said:

Grrr - it was just the outer shell. The next layer has no cracks. Sorry for the false alarm! 

 

I sure hope this isn't just going to peel off layers until nothing is left! 

 

It should develop a crack within 3 or 4 cycles. This is the final act. It won't be long now. Did the outer layer come off intact? You can save it in case the final specimen seems thin and fragile. I've glued some of mine back into their outer shells for size, aesthetic or structural reasons. In some cases it helps to explain how they were formed to those just starting out with MC fossils.

[Patrick K.]

Wellllp…..the promising shaped concretion above was a dud :/ 

 

 I let it dry outside, it cracked in half from the sun,  and I could see there was no fossil matrix in the seam. A hammer confirmed that suspicion 

 

 

90% of the rest of the ones that have opened are duds. Almost all of the large concretions were duds or pretty poor Essexella. I’ve got just one mantis shrimp and another poorly preserved shrimp that I don’t think I can get an ID on. The concretions I have left from the 5 trips are all nodules I have little hope for - stuff I would probably leave behind now that I know a bit more. Pretty disappointed in the outcome. 

 

Any guesses on this one? 

 

I’d had about 3/4 full of a 5 gallon bucket that looked good. These are the last of the large ones I’d had high hopes for that I tapped open today. pffft 
 

And boxes of very well inspected junk from freeze thaw and tapping. 

 

I’d read the rough estimate that 50% of Pit 11 Mazon concretions had fossils, and 50% of those are Essexella. I wasn’t expecting anything close to that but the darned fossil gods were not nice this season! 

Edited June 22, 2023 by Patrick K.

[Mark Kmiecik]

Yeah, I know that feeling. Some sites I collected were 100% Essexella of the ones that contained fossils. Once you become familiar with an area you get an idea where the "good stuff" is. Did I mention it takes years to develop that sense. Taking detailed field notes helps.

[stats]

The percentage of concretions with fossils varies for each locality.  Pit 11 can be very tough, while some terrestrial sites can be very rich.   The best shapes do seem to have the greatest chance.

 

Check this like out.  I always wonder if there is a selection bias as to which concretions became part of the study.

https://www.esconi.org/esconi_earth_science_club/2022/08/mazon-monday-126-relative-abundance-of-different-mazon-creek-organisms-fossil-paleontology-mazoncree.html

 

Cheers,

Rich

 

[RCFossils]

This is a very nice example of the rare shrimp Kellibrooksia.

Congratulations on a fantastic find.

[stats]

On 6/23/2023 at 7:07 AM, RCFossils said:

This is a very nice example of the rare shrimp Kellibrooksia.

Congratulations on a fantastic find.

That is a nice one!

 

Cheers,

Rich

 

[Patrick K.]

15 hours ago, Mark Kmiecik said:

Yeah, I know that feeling. Some sites I collected were 100% Essexella of the ones that contained fossils. Once you become familiar with an area you get an idea where the "good stuff" is. Did I mention it takes years to develop that sense. Taking detailed field notes helps.

 

Thanks Mark - I've only collected a small area of Pit 11 in the State Park - I honestly can't imagine a late-comer and weekend warrior to Mazon collecting like myself being able to come up with a pattern, considering the scarcity of nodules nowadays and with such a small hunting window. Did I mention that I hate tics? With a frothing passion! And I'm super allergic to poison ivy!  I do have the map from the ESCONI presentation that has a few general area's with handwritten suggestions though, I'll pay more attention to that in the future! 

 

16 hours ago, stats said:

The percentage of concretions with fossils varies for each locality.  Pit 11 can be very tough, while some terrestrial sites can be very rich.   The best shapes do seem to have the greatest chance.

 

Check this like out.  I always wonder if there is a selection bias as to which concretions became part of the study.

https://www.esconi.org/esconi_earth_science_club/2022/08/mazon-monday-126-relative-abundance-of-different-mazon-creek-organisms-fossil-paleontology-mazoncree.html

 

Cheers,

Rich

 

 

I have read most of the Mazon Mondays and I had not come across this one. 63% duds makes me feel a bit better! The ones I am opening from this locale are all steel grey inside - seem to look different than the pictures of lots of good specimens I see - is that common for duds? Or are the ones with the more rusty hue just develop that over time after opening? 

 

On 6/23/2023 at 7:07 AM, RCFossils said:

This is a very nice example of the rare shrimp Kellibrooksia.

Congratulations on a fantastic find.

 

Thanks! I of course did go to your gallery here right after I opened it to ID it, thanks again for that treasure trove of info! As you can probably see I opened this one with a hammer blow unfortunately it didn't open perfect, but I still love it!  This was after a few dozen freeze thaws - I was convinced by that point I had only duds or essexella. 

 

 

[Patrick K.]

 

 

2 hours ago, stats said:

That is a nice one!

 

Cheers,

Rich

 

Thanks Rich! 

 

[Mark Kmiecik]

On 6/22/2023 at 10:44 PM, stats said:

I always wonder if there is a selection bias as to which concretions became part of the study.

 

The major bias involved in this type of study are the concretions that experienced collectors leave behind because they already have all the lesser quality specimens they desire. The lesser quality specimens never become part of the study since experienced collectors are the ones most likely to participate in the study and the ones most likely to benefit from the results. It's a self-defeating activity in that those who initiate the study are misleading themselves.

[stats]

1 hour ago, Mark Kmiecik said:

 

The major bias involved in this type of study are the concretions that experienced collectors leave behind because they already have all the lesser quality specimens they desire. The lesser quality specimens never become part of the study since experienced collectors are the ones most likely to participate in the study and the ones most likely to benefit from the results. It's a self-defeating activity in that those who initiate the study are misleading themselves.

Agreed.  That is the bias I was think of too.  The leaverites never make it into the statistics.  It definitely will inflate the success rates.

 

Cheers,

Rich

 

[stats]

On 6/24/2023 at 12:39 PM, Patrick K. said:

 

I have read most of the Mazon Mondays and I had not come across this one. 63% duds makes me feel a bit better! The ones I am opening from this locale are all steel grey inside - seem to look different than the pictures of lots of good specimens I see - is that common for duds? Or are the ones with the more rusty hue just develop that over time after opening? 

Concretions from each locality, and even sub-locality have a different look.  After a little bit of experience, you will notice the pyrite rich black concretions from the Morris area, the layered look to river concretions, and the gray ones from Pit 11.  The red is the iron rusting.  The best concretions are weathered, but not too much.  A little rusting brings out colors.  Pit 3 concretions can have a cream center, but there are dark grey and even greenish colored ones from there, Pit 2, and Pit 4.  Braceville concretions have a acid burned look from the sulfur.

 

The shape and color of concretions could be a whole long discussion.  By shape, you can sometimes make an pretty good guess of the contents.

 

@flipper559  had a great concretion display at the ESCONI show.

 

 

Cheers,

Rich

 

Edited June 25, 2023 by stats

[hiposong]

Cool! Like opening a blind box.