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Home Conodont Extraction


cngodles

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So, in trying to identify my local limestone for sure, I've gotten the need to try to extract conodonts, and I'd for sure like to see other microfossils. I know this has been discussed here before, but I was wondering what might be the correct or tried and tested method for home, using obtainable chemicals. The last thread I found was talking about lab processes and clouds of white smoke.

 

I've heard different things from using acids (Vinegar), Hydrogen Peroxide (3% limit at Walmart), to Kerosene. Also a need for sieves, filters, etc.

 

Curious for a guide or advice for effective home methods.

- Clint

Fossils of Parks Township - ResearchCatalog | How-to Make High-Contrast Photos

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Have not done this myself, but do you know this book:
"The Great Fossil Enigma - The Search for the Conodont Animal"

by Simon J. Knell.

There is no direct recipe in this book, but you can see also the progress of methods in extracting conodonts.

Franz Bernhard

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You need to buy concentrated acetic acid from a chemical supply company or via the internet.

 

See:

Jeppsson, Lennart, et al. “The Optimal Acetate Buffered Acetic Acid Technique for Extracting Phosphatic Fossils.” Journal of Paleontology, vol. 73, no. 5, 1999, pp. 964–972. JSTOR, www.jstor.org/stable/1306854. Accessed 31 Jan. 2021.

 

https://www.researchgate.net/publication/304425532_Extraction_Techniques_for_Phosphatic_Fossils

 

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My goal is to leave no stone or fossil unturned.   

See my Arizona Paleontology Guide    link  The best single resource for Arizona paleontology anywhere.       

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On 1/31/2021 at 1:09 AM, FranzBernhard said:

do you know this book:
"The Great Fossil Enigma - The Search for the Conodont Animal"

Well, I will soon. I bought it. Can't have enough science books.

 

I may have to track down some acid, and likely some additional sieves. Haven't found that chapter yet. I found the chapter! Quite an interesting book.

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So from the preparation/extraction chapter, I'm going to first try Argillaceous (fine shale) rock extraction. There were three methods listed, but I'm going to try the Petroleum spirit method, as I have minerals spirits immediately available. Another method describes 15% Hydrogen peroxide, but I'd have to order and wait for that. The third method requires Sodium hypochlorite, which I think is bleach. It takes 3-4 weeks and still seems to require an acid bath afterwards. So I'll go with what seems like the path of least resistance.

  1. Scrub with bristle brush.
  2. Dry in an oven for an hour at 120°C (248°F)
  3. Break up the sample using a hammer or other crushing tool into approximately 2 cubic centimeter pieces. Remove any fine powder. Place 500g into a 2000ml beaker.
  4. Cover sample in beaker with mineral spirits (specifically says petroleum or white spirit). Soak for 24 hours.
  5. Drain and filter the spirits off. Can reuse them.
  6. Cover sample with hot water and a few drops of detergent. Boil until rock disintegrates into a mud. How long this takes? I don't know.

I am going to try this experiment over the next couple of days and see if I can turn my shale into a mud. It is said not to work well on black shale.

 

Filtering/extraction with sieve is later, and I'm not sure exactly which size I'm going to want to get.

 

Until next time.

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  • 2 weeks later...

An Update.

  • I gathered some rocks, about a foot above the limestone layer.
  • I dried them in the oven for 90 minutes, at 250°F.
  • I broke them up into smaller pieces.
  • I soaked these in mineral spirits for about 48 hours.
  • I drained off the mineral spirits into a flask to save for another time.
  • I boiled the rocks for probably 6 hours or so. They did not disintegrate much.
  • I sieved the boiled remains through a #35, #60, and #200 container.
  • Upon microscopic inspection, I'd say about 99.9999% shale flakes. The only thing I was remotely curious about was in the center of the photo below. But I didn't recover it.
  • I did let the sieves dry out to see if that would give me anything better visually. The view does improve, but no microfossils.

 

9FC23A34-0C53-40DB-BE42-BB5AC5A9995E-sca

 

I think I was much too close to the calcareous limestone. I believe I used a truly black shale. I do know of more mudstone type rocks about 5 feet further up. I will repeat this experiment with these. I had left the same rocks in a bin of water quite a while back, and pieces completely disintegrated after weather exposure for a few months. Here's hoping. I did take the rocks and tried a simple soak in 3% hydrogen peroxide. They did bubble a lot, but after sieving, etc, I noticed no difference in the result.

 

7AEBBF48-488E-41E5-947B-DFF89A4F86BB-sca

 

 

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  • 11 months later...

So it's been quite a while since I've talked about this topic. I haven't tried it yet, but I find the method described here as promising to try again. It would probably be done on limestone instead of dark shale.

 

https://storymaps.arcgis.com/stories/8cbe8e656c7b4ccaa0a8af717d7ef85c

 

Methods


1. Extract about 5 kg of sample from NP layer.

2. Crush about 2 kg into pea sized pieces.

3. Use dry sieve mesh sizes 18-20 to sort out finer pieces and minimize excess limestone reacting with acetic acid.

4. Dissolve 450 g of gravel with 3 gallons of 10% acetic acid.

5. Pour partially dissolved sample into wet sieve and then pour that into a beaker and place in heater to dry.

6. Brush contents into petri dish and examine under microscope.

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Fossils of Parks Township - ResearchCatalog | How-to Make High-Contrast Photos

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