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andreas

Ladinian Ammonoid Prep

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andreas

Servus folks

It is raining the whole day and now it starts snowing.

This year’s collecting season is over and prep work has started two weeks ago. Always preparing in the lab makes no fun to me. So I took a break and wrote this short story about the preparation of a Ladinian ammonoid slab.

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The first picture shows the situation when I found the location. If you look carefully you can see some round cross-sections of orthocone nautiloids and some longish cross-sections of ammonoids. At this moment it was only a guess what ammonoid species was hidden behind this longish edges. My first intention was Epigymnites and therefore Ladinian in time.

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The second picture show the worked out blocks comparing the fossils. At this moment I knew that it was Ladinian and that my guess was right for the genus. I knew also that there were 3 individuals of Epigymnites in the parts.

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The third picture shows the result of roughly 10 hours prep work. Unfortunately the preservation of the ammonoids was not good as expected. But in the Triassic strata of Austria Ladinian locations and ammonoids are scarce to find.

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The last picture shows the result of my preparation work. The plate shows Epigymnites cf. moelleri MOJS.(uppermost one) The typical double row of fine knots is visible only on this amonoid.

Alas not the best preservation but absolutely worth to put it into my Triassic ammonoid collection.

kind regards

Andreas

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squalicorax

Congrats and great photo documentation!

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Beach Boy

Story well told Andreas thanks for sharing your finds.

Regards

Dave

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Fossildude19

Thanks for the walk through, Andreas - looks pretty good to me. :)

Well done!

Regards,

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Wrangellian

Andreas, you have a well-trained eye - I would have never noticed anything there in that first pic! And it's quit a transformation between that and your finished product, which anyone should be happy to have in their collection! However (Fine, leave it to me to nitpick, folks), but I see tool marks all over those ammonoids - is there no way to avoid that?

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andreas

Thank you all for your comments!

@eric(wrangelian) This is what I have meant with bad preservation. What look like toolmarks are parts of the ammonoid where the calcified shell doesn't split. Sure there are some toolmarks too but 95 % of this rough areas are non splitting parts of the ammonoid shell.

Instead of splitting between the sediment ond the ammonoid shell, a part of the shell break out and the result is this rough surface. One can only avoid this by grinding or scratcing the sediment by hand down to the shell i.e.down to the very thin black oxide crust of the shell. But on such parts this crust is mostly not given. You can see this by the lighter look of this rough areas. I am no great friend of grinding fossils. Maybe they would look better and smoother on the picture but in reality more of the fossils(original shell) will be destroyed. Scratching under Micro is OK but that needs time, time, time,....time that I do not have.

Most parts of the rough areas lay a little above the original shell. I tried to stop there. So I can still later do more prep on them. If I wish :)

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Wrangellian

That makes sense.... At least if there are bits of matrix left on the shell (as opposed to pits in it) you can go back and remove that later. I'm sure all prep jobs are a function of how much time you have.

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