Colour banding in ammonoids

Hajar

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I just noticed that this little basal Triassic ammonoid has very distinct (when wet) orange colour bands spaced at about 2 mm apart, close to, but crossing, the very fine growth lines. First time I see this, though I know it has been recorded from Triassic ammonoids elsewhere. Does anyone else have examples?
 

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Hajar

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There are some examples from Nevada here showing broadly similar patterns.
 

Hajar

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The Crittenden Springs specimens are younger (Smithian) than this example (low in Griesbachian).
 

DWhatley

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I know you (Kevin) are kind of against messing with fossils but is there something non-destructive you can put on them that will allow them to show the colors like that (like an oil) without having to wet them?
 

Hajar

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I wouldn't coat this D. It could be an important specimen.

Does anybody know of pre-Triassic examples of ammonoids showing relic colour patterns?
 

Architeuthoceras

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Hajar is correct, it may be important, wetting it once in a while to photograph is enough. You never know how some coating will react with the fossil, or color in this case.

I did find some Mississippian Goniatites with a dark pattern on a light calcite replacement, looked kinda like the pattern on Nautilus shells. Then I found another with the plant roots still in place and saw what really formed the pattern. :oops:

Klug et al, have something to say, especially about the radial color bands, whether this applies to all radial bands I don't know.
 

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