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GeneralThe strange structure into silicitolite

11th Sep 2018 15:57 UTCPavel Kartashov Manager

It was found on school-yard of one of schools of Voronezh city in pile of crushed stone. The rock is silicified sedimentary carbonate rock (I don't know English term, but in Russian it named опока - silicified marl).

It looks like not some fossil, but trace of a some process. Quite enigmatic formation.

11th Sep 2018 17:59 UTCWolfgang Hampel 🌟 Expert

Pavel,

I have never been particularly good in sedimentology but I guess it is some kind of flute cast.

Best,

Wolfgang

12th Sep 2018 13:36 UTCmaurice supertramp

interesting pattern;

it has some resemblance with the so called chevron casts (similar to groove casts),

https://www.google.it/search?biw=1517&bih=695&tbm=isch&sa=1&ei=QwSZW8SXE4_osAfh1KCAAQ&q=chevron+casts+geology&oq=chevron+casts+geology&gs_l=img.3...321835.327401.0.327935.21.18.0.0.0.0.561.3639.3-2j3j3.8.0....0...1c.1.64.img..13.4.1883...0j35i39k1j0i19k1.0.TDqN56uv4vk#imgrc=SPajtkcGm1U2EM:

but there's something not matching with that; so, if the rock is not of turbiditic origin, I would not exclude a biological origin (maybe an ichnofossil)

best regards

12th Sep 2018 17:56 UTCAlfredo Petrov Manager

Are these related to cone-in-cone structures?

12th Sep 2018 19:05 UTCGregg Little 🌟

There is a species of bryozoan called Archimedes which has a central solid spiral axis of similar shape, although this one seems large and the spiral is not readily apparent; would have been good to have something for scale. Some fossils have been found in Permian deposits in Russian. Just put "Bryozoan archimedes" in a search engine for photos. If it is this fossil and the preservation is good, then you should see many pores on the animal's surface.

12th Sep 2018 22:58 UTCPavel Kartashov Manager

Length of the stone is approximately 60 cm.

13th Sep 2018 00:10 UTCGregg Little 🌟

That would make the fossil about 30 to 40 cm long which is large but not exceptional as some of the photos of Archimedes on the internet approach 50 cm and as well these could be incomplete fossils.

13th Sep 2018 08:36 UTCUlf Nyberg

To me that can be a fossiled corall

Regards Ulf

13th Sep 2018 09:33 UTCKeith Compton 🌟 Manager

I'd like to think of it as a fossilised ant antenna from some long lost prehistoric ant (he'd only be about 8 feet long !!:-)) !! More wine for me!!

13th Sep 2018 12:24 UTCPavel Kartashov Manager

No more wine for Keith, it's enough for her...

13th Sep 2018 16:36 UTCGregg Little 🌟

Greetings Ulf;

I too checked out the rugose corals earlier. The structure is not quite right because those whorl ridges have a distinct separation between them; this is where the delicate fronds of the bryozoan probably attach, if this is a bryozoan.

Rugose corals have similar structures in the form of finer growth lines that ring the cone of the body of the coral. These are much less pronounced than the ones in Pavel's picture. I also considered the various straight shelled gastropods and cephalopods but the internal structure just doesn't seem to match up.

Regards, Gregg

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