Upper Cretaceous Blister Pearl?

[PFOOLEY]

I recently recovered this Cameleolopha bellaplicata valve from the Upper Cretaceous (Middle Turonian) Prionocyclus hyatti ammonite zone of the Carlile Shale here in New Mexico.

 

 

I was initially delighted with its preservation and upon further inspection, noticed a feature on the inside of the valve...

 

 

...I thought it may be a blister pearl. I reached out to Dr. Spencer Lucas (New Mexico Museum of Natural History and Science) to get his thoughts. His response was: "years ago, we found a Texigryphaea near Tucumcari with a similar pearl in it."  Pleased with that response I turned to the interwebs for more information.

 

V. Friedman and A. Hunt (2004) wrote and abstract on Fossil Pearls from the Upper Cretaceous of Texas in which they are reporting Cenomanian and Turonian occurrences...I plan to reach out to Adrian Hunt to get his thoughts on this specimen as well.  I also found a paywalled paper on Fossil Pearl-growths written by R. Bullen Newton (1908) in the Journal of Molluscan Studies and have requested access to that literature. 

 

Then I turned to our Forum.

 

@LanceH found a pearl in the Kamp Ranch Limestone...

 

 

...as did @Mikrogeophagus ...

 

 

... @Bobby Rico has a blister pearl specimen from the Norfolk Coast  (UK)...

 

 

...and @rocket is working on some Campanian Ostrea semiplana pearls from Hannover, Germany.

 

 

There are numerous threads here on the forum where fossil pearls are discussed. These conversations, along with some modern representation from interweb imagery...

 

 

...have led me down an unfamiliar path. My understanding is that these fossils are uncommon. And with all that said, I pose this question...

 

...is this a fossil blister pearl?

 

 

I would love to hear your thoughts.

 

Thank you for your time.

[Mikrogeophagus]

I have no idea myself, but it's got a suggestive shape. Will be following this thread  Cool find!

[DPS Ammonite]

What is the tan material labeled 1? Could it be the sediment that filled the bivalve, AKA internal mold and steinkern? Is 1 shell material? Is 2 shell material which may be part of the other valve that is mostly gone? 3 might be a mold of a depression in the other shell.

 

Please let us know what 1 or 2 are and if the fizz in acid.

 

 

 

Edited April 1 by DPS Ammonite

[rocket]

interesting find, hm, might be a blister pearl, my vote is 60:40 yes

[PFOOLEY]

Thank you for the comments... I will keep up the inquiry.

 

For some comparison, I dug up some other C. bellaplicata upper valve specimens...

 

 

 

 

 

 

 

 

 

...and a lower valve.

 

 

[rocket]

definitely look different, "blisterpearlfree"

[rocket]

there is a small paper about an middle jurassic blister pearl from germany, see p 43/44 in the attached paper

 

perle_dogger_osterfeld.pdf

Edited April 11 by rocket

[PFOOLEY]

Thank you, @rocket!

 

 

In 1974, on the site of the former brickworks Osterfeld carried out extensive earthworks and a sports facility was to be built. For a short time, the Jura there was closed from the Lias a to the middle Dogger. Since the layers were placed almost vertically due to the resin folding, it was possible to compare the geological periods during the construction period to literally migrate and simply collect the traditional testimonies. However, when insatiable fellow collectors arrived with heavy equipment (it (even excavators were used), access had to be prohibited and fossil collecting had to be stopped. During the time of free access, the author made some remarkable discoveries (GRABENHORST 1978, Disclosure 29). Another one will be presented here.

 

Through the work of the bulldozer was in the clays of the middle dogger A narrow band was exposed above the Parkinsonia layers, which consisted almost exclusively of mussel and ammonite shell. When fresh from the mountains, the individual shell fragments were largely extremely damaged vivid mother-of-pearl shimmer. At one point in this band of shills a fell compact larger lump, which after rough cleaning turns out to be one completely preserved oyster. The two are still in their original position The shells were gaping at the rear edge and were covered with scallops and clay caked. The find was packed and then thoroughly watered at home. The shells could then be easily separated from each other. After cleaning, residues of others were found on the outside of the shell Oyster shells. The animal had therefore socialized with other individuals lived on an oyster bed. Both shells show deformations were probably created by mountain pressure during the Harz folding. The The dimensions of the oyster are: length 9 cm, width 6 cm.

 

The contents of the oyster were easily crumbled in water. After pouring off the cloud again, only pieces of scallops remained in the bowl — and, immediately striking, a larger, compact pearlescent one Piece of irregular shape. When examining under the binocular A shelly structure was visible. There were thin layers of mother-of-pearl formed concentrically around an irregularly shaped core. It is about thus a fossil pearl. The dimensions of the pearl are: 20 x 13 x 12 mm.

 

Since the oyster shells do not have a layer of mother-of-pearl on the inside, It can probably be ruled out that the pearl was created in the shell that was found is. It is likely due to wave movement together with Schill into the gaping, already dead oyster has been washed in and is over there It has been well protected for millions of years.

[rocket]

2 minutes ago, PFOOLEY said:

Thank you, @rocket!

 

looks a bit similar to yours

If you need a translation or explanation about the site let me know

The site is closed since 40 years, but I do have some papers about it and was there as a student, looooooooooooooooong ago...

[PFOOLEY]

Just now, rocket said:

...If you need a translation...

 

Google helped me.  I've posted above.