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Norki

Lake Diefenbaker - Giant placenticerids and some marine vertebrates

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Norki

Now that the weather has finally warmed up a little in these parts and the ice has gone off the lake, my friend and I were able to return to Lake Diefenbaker for some back country fossil hunting. In addition to scouting some new potential sites, we were particularly interested in visiting the site documented in this post here, which has already proven to be a diverse and abundant fossil bed. Hunting the beaches at this time of year is particularly lucrative, as the flood waters from the mountains have not yet reached the lake, and water levels can be as low as five meters below the high water mark. Reaching these sites can be a challenge however, and a good Zodiac raft seems to be a must.

 

A view from base camp... Our typical MO is to launch with all of our gear, set up a camp in a sheltered spot like this, then take day trips with the raft out to productive areas.

 

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Once at the site, we began encountering giant ammonites like this placenticeras meeki:

 

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These occur somewhat frequently in the Bearpaw formation in general, but it's rare to find intact and relatively uncrushed ones. Here are some photos of the largest we encountered (sorry for small photo size and weird angle):

 

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This smaller placenticeras meeki has more or less all of the surface shell material preserved:

 

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And of course, a somewhat beefier placenticeras intercalare with some impressive suturing and ornamentation:

 

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Now, here are some photos of some vertebrate remains also found within the nodules. These (and naturally any of the other fossils we've found that they determine as important) will be delivered to the Royal Saskatchewan Museum next time we arrange to go to the site with them. I believe that these are all fish remains aside from the vertebra, perhaps someone could shed some light here:
 

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Bonus bullsnake photo:

 

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PS - I'm getting this error message when I try embedding photos into the post, "The link could not be embedded because of an unexpected error: Forbidden: 'Something went wrong. Please try again.' "

 

Anyone know what's up with that?

 

 

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Uncle Siphuncle

Absolutely stunning finds!  I'm used to seeing dull Texas steinkerns.

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Fossildude19

It is best for all if you upload the photos directly to the Forum.  ;)

Links to web hosting sites can expire or images get deleted , leaving a post with no images. 

That can defeat the purpose of sharing these images with th internet.  :(

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Norki
43 minutes ago, Fossildude19 said:

It is best for all if you upload the photos directly to the Forum.  ;)

 

I get an error message when I try that as well, " The page you are trying to access is not available to guests, but may be available if you sign in. "

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RandyB

Here are the pics:

60052272_10218113274837284_2427643918041481216_o.thumb.jpg.91bba184fbbb6b2a2aaa0600cc4facf4.jpg60196609_358977168063758_650098374615236608_n.thumb.jpg.67c48f30bde860513a375497ea1ed9f1.jpgDSC_0658_e2.thumb.JPG.e9452ceb3b4c0e7fb91bd245b3f1bc5a.JPG59822871_848534042198782_8980434491726102528_n.thumb.jpg.c70c7a389d1f0862b52673277f0ee089.jpg60426237_2333575643330757_5529727242063577088_n.jpg.6bea06f6aa4fc0f459bdd2fccff474aa.jpg

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RandyB

I will need to resize the one with sutures, its too  big a file, will come back to it

60625939_2104911299617693_170268914683478016_n.thumb.jpg.27dc14aeff44d33d8f4919a03d2aed0a.jpg60930365_302903513996803_6786565729505247232_n.thumb.jpg.cd8b094c0c973bd01ff0e6f35c10cdc0.jpg

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RandyB

60590077_435263667252279_3596394073646170112_n.thumb.jpg.fed81bd9d37b3ea24c0cf8dd342a7623.jpg61059906_305980686966982_813533369265553408_n.thumb.jpg.798a5754e40b89cb37ae6838d93c72a8.jpg60291831_10218113285397548_5954485591943938048_o.thumb.jpg.cac3ce850fa7953b8711e2ace9c1d75e.jpg

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RandyB

Here we go 

20190520_202155.thumb.jpg.4fac4c1f0c11e15ec1d5b48113e5b757.jpg

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Tidgy's Dad

Stunning photos and stupendous finds.

Wow! :drool:

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Wrangellian

Great stuff.

Do you have to stabilize those ammos with anything or are they solid enough to handle? The pieces I've got (which we determined are probably from your area) seem a little fragile/flaky but I'm resisting coating them with anything.

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Norki
1 hour ago, Wrangellian said:

Great stuff.

Do you have to stabilize those ammos with anything or are they solid enough to handle? The pieces I've got (which we determined are probably from your area) seem a little fragile/flaky but I'm resisting coating them with anything.

It really depends. Some of them are flaky, chalky, and prone to crumbling, but these are typically just left in the field. Most are fairly well preserved and don't need any kind of stabilizing at all, besides glueing broken parts together. Mind you it's rare to find any that dont have any crumbling at all, but usually it's a neglible amount that doesn't really impact the integrity of the specimen. The material of the matrix seems to play a part in how well preserved they are, but it seems like it generally has to do with how much ground water has seeped into the concretion through cracks and degraded the nacre over the years.

 

When I do have to stabilize them, or if I want to bring out the colour of the nacre, I'll coat them with resin. This is sometimes a bit of a gamble though - occasionally there will be minerals either in the matrix or precipitated on the shell itself that are soluble with the resin, which causes ugly brown staining... Interestingly enough, it's usually the ammonites with the well-preserved, pearly nacre that react badly to resin, so these are usually left as they are or given a quick wax. The ammonites with only thin, compressed or crushed nacre tend to not only be more colourful, but also react better to resin (think something along the lines of the St. Mary river placenticeras that are harvested for ammolite)... There's definitely a broad spectrum of nacre preservation, which is part of what makes finding these so fun - each one is subtly different and beautiful in its own way. To answer your question though, I usually don't mess with them too much.

 

There's actually a paper out there somewhere that proposes a "nacre preservation index" for late cretaceous western interior seaway molluscs that I'll have to look for and link here some time (I've only seen it cited in another paper). It's something that I should probably spend more time learning about, since there's doubtlessly a way to reliably classify these ammonites by the state of their nacre.

 

@RandyB

 

Thanks a lot for sorting out the images. Not really sure what's up on my end.

 

 

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FossilDAWG

Great photos and great fossils!  :wub: :wub: :wub:  Thanks for showing them to us.

 

Don

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Wrangellian
3 hours ago, Norki said:

When I do have to stabilize them, or if I want to bring out the colour of the nacre, I'll coat them with resin. This is sometimes a bit of a gamble though - occasionally there will be minerals either in the matrix or precipitated on the shell itself that are soluble with the resin, which causes ugly brown staining... Interestingly enough, it's usually the ammonites with the well-preserved, pearly nacre that react badly to resin, so these are usually left as they are or given a quick wax. The ammonites with only thin, compressed or crushed nacre tend to not only be more colourful, but also react better to resin (think something along the lines of the St. Mary river placenticeras that are harvested for ammolite)... There's definitely a broad spectrum of nacre preservation, which is part of what makes finding these so fun - each one is subtly different and beautiful in its own way. To answer your question though, I usually don't mess with them too much.

 

There's actually a paper out there somewhere that proposes a "nacre preservation index" for late cretaceous western interior seaway molluscs that I'll have to look for and link here some time (I've only seen it cited in another paper). It's something that I should probably spend more time learning about, since there's doubtlessly a way to reliably classify these ammonites by the state of their nacre.

I wonder if there is something better than resin to use: I don't imagine resin is in any way reversible, something fossil conservators value these days. I don't think Super Glue is easily reversible either but maybe it doesn't react with those minerals like resin does? I don't know about bringing out the colors either, but for consolidation purposes at least, it's usually Paraloid/Acryloid (for reversibility) or Super Glue/Crazy Glue that are recommended. But only if it's needed.

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Manticocerasman

gorgeous ammonites :drool: :envy:

 

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Monica

wow

:default_faint::drool::wub::ammonite01:

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