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Colorado Prospector - Gem and mineral prospecting and mining forums _ Fossil Finds, Processes, Adventures and Outings _ Hoploscaphites nicoletti

Posted by: Gene Kooper Jan 29 2016, 12:06 AM

I've been enjoying the last week or so packing everything up after 16 years in one house...Sigh.

However, it's not all bad. I finally unearthed several boxes of ammonite fossils I hadn't seen for 15 years. Many, many years ago, I visited a friend in Bismark, ND who had discovered a great ammonite locale in north-central South Dakota. The most common ammonite that we found on that field trip was Hoploscaphites nicoletti.

Here are a few photos from the first box I opened up.

Front and back of several Hoploscaphites nicoletti specimens. The back side of the largest fossil was not completely mineralized on the inside so you can see the structure of the chambers and suture patterns. In one of the other boxes I have a large specimen on matrix where the inside is also hollow. It has some amazing structural features including the siphuncle tube that allowed the ammonite to pump air and water to and from the chambers to control buoyancy. I just need to figure out which box it's in. chin.gif

[attachment=9136:DSCN1705.JPG]

[attachment=9137:DSCN1708.JPG]


Front and back of three Hoploscaphites nicoletti pieces that show the ribs and color fairly well.
[attachment=9138:DSCN1706.JPG]

[attachment=9139:DSCN1707.JPG]

If I ever retire, I hope to finally have the time to prep some of the larger clusters.

Posted by: Crusty Jan 29 2016, 05:39 AM

awesome pieces!!

Posted by: swizz Jan 29 2016, 07:51 AM

Those are stunning Gene! worthy.gif
If they are retaining the opalescence (which they are!), aren't they referred to as Ammolite? Of far more value and desire when in that condition of find.
What is the approx size of the one's you pictured?

Posted by: johnnybravo300 Jan 29 2016, 09:23 AM

Those are amazing.

Posted by: Gene Kooper Jan 29 2016, 09:26 AM

Oops, I knew I was forgetting something. The specimen with the open chambers is approx. 3-1/2" x 2-1/2" in size. The large piece in the other group is 2" x 3". From what I collected, Hoploscaphites nicoletti don't get much bigger than this. I have a large plate approx 1 foot in diameter containing a dozen iridencent specimens.

I think you are right swizz. These could be called ammolites because of the iridescent nacre. However, the nacre is very thin, so not like the thick nacre of some Placenticeras specimens. I have a few Hoploscaphites nebrascensis that have the deep ruby-red and bright green colors commonly associated with ammolites. They are 4" to 6" in diameter.

I haven't done any cleanup or prep on these. This is what they look like right out of the concretion. One of the interesting things is that the shell initially grows in a spiral and then has a straight section.

Posted by: MikeS Jan 31 2016, 11:22 AM

Beautiful fossil specimens Gene! Very cool. thumbsupsmileyanim.gif

Posted by: Gene Kooper Feb 3 2016, 12:44 AM

Nature repeating itself. Polar Stratigraphic Clouds aka "nacreous" clouds aka "ammolite" clouds (for swizz).

These photos come from http://www.spaceweather.com

QUOTE
Also known as "http://www.atoptics.co.uk/highsky/nacr1.htm" clouds, PSCs form in the lower stratosphere when temperatures drop to a staggeringly-cold -85ºC. High-altitude sunlight shining through tiny ice particles ~10µm wide produce bright iridescent colors by diffraction and interference.


Here is a http://spaceweathergallery.com/indiv_upload.php?upload_id=122362 captured by U.K. photographer, Andrew Greenwood.




Posted by: swizz Feb 3 2016, 12:15 PM

I never knew there was such a phenomenon, very cool and well named!

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