frankh8147 Posted April 20 Share Posted April 20 Hello everyone! Recently, I found a gastropod imprint with a weird zig-zag pattern in the Cretaceous Merchantville formation (hard pan) of New Jersey. After showing it to a few folks, it was suggested that it may maintain its original color pattern. We aren't aware of this occurring on the Atlantic Coastal plane so I wanted to get more opinions on it and if it could be that. Thanks for your time! Frank 2 Link to comment Share on other sites More sharing options...
Rockwood Posted April 20 Share Posted April 20 It seems possible, but to be sure of it one would need to consider the effect that contouring might have on mineralization. 1 1 Link to comment Share on other sites More sharing options...
Mahnmut Posted April 20 Share Posted April 20 Interesting, do you have the possibility to take microscopic pics? A good magnifying glass may be enough to see more. @FranzBernhard, what do you think? Yours are somewhat younger, but still amazing... Best regards, J 1 Try to learn something about everything and everything about something Thomas Henry Huxley Link to comment Share on other sites More sharing options...
ted coulianos Posted April 20 Share Posted April 20 Color pattern or just a reflection of ornamentation on the shell whorl? Have you tried shining longwave UVA (315-340nm) ultraviolet light on it? I know that often brings out the spots & color patterns on fossil shells of younger age (Pliocene Volutes, Cones, Miters, etc from Florida); perhaps it will bring out some sharper patterns on your find. Worth a shot.... Link to comment Share on other sites More sharing options...
FranzBernhard Posted April 21 Share Posted April 21 I don´t know. Its said, its an imprint, so it can not be relic color pattern? @Rockwood and @ted coulianos said, it could be due to contouring/ornamentation? Possibly yes. Better pics needed to say something more definitive. Franz Bernhard 1 Link to comment Share on other sites More sharing options...
Rockwood Posted April 21 Share Posted April 21 27 minutes ago, FranzBernhard said: its an imprint, I'm not so sure that is completely true. @frankh8147 your thoughts? 1 Link to comment Share on other sites More sharing options...
frankh8147 Posted April 21 Author Share Posted April 21 6 hours ago, Rockwood said: I'm not so sure that is completely true. @frankh8147 your thoughts? It is the impression side of the fossil but we need to take a look at it better under magnification Link to comment Share on other sites More sharing options...
frankh8147 Posted April 21 Author Share Posted April 21 17 hours ago, ted coulianos said: Color pattern or just a reflection of ornamentation on the shell whorl? Have you tried shining longwave UVA (315-340nm) ultraviolet light on it? I know that often brings out the spots & color patterns on fossil shells of younger age (Pliocene Volutes, Cones, Miters, etc from Florida); perhaps it will bring out some sharper patterns on your find. Worth a shot.... We aren't sure if it will work on something this old but we are actually trying that today. I'm donating it to the MAPS Collection (New Jersey) and they have an ultra violet light. Link to comment Share on other sites More sharing options...
TRexEliot Posted April 21 Share Posted April 21 On 4/20/2024 at 3:26 PM, Mahnmut said: good magnifying glass may be enough to see more. *Tips fedora* 1 Link to comment Share on other sites More sharing options...
Rockwood Posted April 21 Share Posted April 21 55 minutes ago, frankh8147 said: It is the impression side of the fossil but we need to take a look at it better under magnification Do you have the actual body fossil. Without it I have to agree with @FranzBernhard. Relic color pattern is virtually impossible. Far more difficult to prove at best. 1 Link to comment Share on other sites More sharing options...
Mahnmut Posted April 21 Share Posted April 21 Hi again. As far as I know the pigments in mollusc shells are rather organic than mineral pigments, so I think the probability is low to have them preserved in a pure impression where the original shell is gone. On the other hand, organic pigments have in some cases been found in much older fossils and who knows what interactions took place between the original shell material and its matrix. After all a 10 gram dead echinoid can change its chemical environment, effectively making a pound of pyrite grow. Ho much pattern is preserved in the process is the interesting part. And maybe there is some original shell left. I am not arguing that it is original pattern, I just argue its looking enough like it to take the closest look you can. Looking at related younger gastropods to see if the pattern would fit could also help, but diversity is high... Best regards, J 2 1 Try to learn something about everything and everything about something Thomas Henry Huxley Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted April 21 Share Posted April 21 While it certainly is possible to preserve colour in shells, as can be seen in this thread, I believe there's a difference in preservation between mineralogical pigmentation - which mostly determines the patterns of light and dark on a shell (through melanosomes) - and organic colour patterns. The latter are much more prone to fading and degradation than the former, which can be found as far back as the Triassic Muschelkalk. See: Whether the same rules for preservation of colour also count for imprints, I wouldn't dare say, although one can imagine that if a thin film of the original shell or organic material were to cling to the impression, it would be possible. I haven't heard of shells using structural pigmentation, though that would be a potential other option. 2 'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett Link to comment Share on other sites More sharing options...
frankh8147 Posted April 22 Author Share Posted April 22 Thanks to everyone who is taking a look. I have a quick update from MAPS Collection curator Ralph Johnson (where I donated the fossil to). As was suggested by others here, it was put under a UV light and I was told the entire imprint area glowed meaning there does appear to be original shell still present. 3 Link to comment Share on other sites More sharing options...
Doctor Mud Posted April 22 Share Posted April 22 Great thread and something I often wonder about. Useful to have this discussion and have links to another thread on here about color patterns on shells. I had never thought about whether color or patterns are mineralogical or pigmentation. I see patterns preserved on Tumidocarcinus carapaces as an example. Some might be due to the location of setae (hairs) or an external expression of internal muscle attachments? Others I’m not so sure. A fascinating subject to think about the original color of the creatures we find as fossils. 1 Link to comment Share on other sites More sharing options...
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