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Figure Stone
I am an avocational archeologist investigating figure stones, my hunting ground provides many unusual fossil finds, probably gathered by ancient people, hence why I easily find them.

This is a crushed echonoid, but has been completely pyritised, so its basically a lump of iron.
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Anonymous
Oh no, here we go again.....
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Figure Stone
wrote:
Oh no, here we go again.....


Have you never heard of pyritised fossils? Anyone familiar with echonoids will recognize the diagnostic structure in my find.
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prep01
Hi, you don't say exactly where this was found? I have never seen a pyritsed echinoid  from the UK but that may just be me! The specimen you have shown us is Echinocorys scutata from the Turonian zone of the 'middle chalk' into the Maastichian in the UK but into the Palaeocene elsewhere in the world.
Colin Huller
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Figure Stone
prep01 wrote:
Hi, you don't say exactly where this was found? I have never seen a pyritsed echinoid  from the UK but that may just be me! The specimen you have shown us is Echinocorys scutata from the Turonian zone of the 'middle chalk' into the Maastichian in the UK but into the Palaeocene elsewhere in the world.


It's a Hampshire find, from the surface of chalk downs, thanks for recognizing the type.
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Figure Stone
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Some other iron rich finds from my site, could the one on the bottom right also be a pyritised fossil?
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nomadiclifeguide
Could someone explain this to me please? I am unfamiliar with this theory.

Thanks
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Figure Stone
 
prep01 wrote:
Hi, you don't say exactly where this was found? I have never seen a pyritsed echinoid  from the UK but that may just be me! The specimen you have shown us is Echinocorys scutata from the Turonian zone of the 'middle chalk' into the Maastichian in the UK but into the Palaeocene elsewhere in the world.


A google search provides no other samples of  pyritised echonoids, so it's not just you, it appears to be a very rare find.
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Figure Stone
Could someone explain this to me please? I am unfamiliar with this theory.

Thanks


I take it you mean why the fossil is iron? Basically the theory goes that the minerals were replaced by iron pyrite.

Pyrite replacement of fossils is often caused by bacteria, in a process called permineralization. Since it requires both aerobic bacteria (which need oxygen to survive) and anaerobic bacteria (which live in places with little to no oxygen) to complete the process, pyritization can only occur in the levels of sediment near the interface between the two zones - and the sediment must have just the right amount of iron, not too much and not too little.

When the body of the unfortunate soon-to-be fossil is first buried, sulfate-reducing anaerobic bacteria begin to consume its organic material, producing sulfide.  

The high concentration of iron in the sediment converts this to iron monosulfide, which is then oxidized into pyrite by aerobic bacteria. This pyrite is deposited onto the surfaces of the decaying organism, forming sparkly pyrite.

Fossils formed in this way can preserve the forms of the soft tissue, a rare event in the fossil world, making them particularly useful in scientific research.

From here: http://www.rockhoundtimes.com/pyritized-fossils.html
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Dirty Pete
Hi,
I think Nomadiclifeguide is referring to the link in your first post, the first item of which suggests that humans were co existing with hadrosaurs.

Cheers,
Pete.
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Figure Stone
Figure stones, very basically: flint tools, worked stones showing a repeat topology of known figurative descriptions and conventions. Scientifically repeatedly proven to be genuine finds of archaeological significance that can be found in ancient layers all around the world. Common figures are a cloaked figure, whales, elephant half, gorillas, apes, monkeys etc, bears, birds, horses. Common convention: head profile shapes, creature front half profiles. Often in tool form, with ochre and other pigments present. An article I wrote a while back, much of which was published in an archeological magazine: https://eoliths.blogspot.com/2017/05/eoliths-flint-tools-and-figue-stones.html
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crusty_rusty59

I'm confused here. Is this a pyrotised echinoid from Hampshire, or is the suggestion that it is from elsewhere?

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Figure Stone
I found it on the surface of  a prehistoric site in Hampshire, there are small traces of yellow ochre on it, so I suggest it was likely used by ancient people, where they got it from who knows, but was likely dug from chalk locally. As far as I can tell it is an extremely rare find, a  google search provided no images of other pyritsed echinoids. Pic: some other iron rich finds from my prehistoric art/tool site, bottom right also looks like a pyritsed fossil, coral, also no results for that on a google picture search.
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prep01
Marcasite / Pyrite is a very common find on many an Archaeological site as it was used to start fires.(with flint),  I am often asked for and supply Marcasite nodules for ancient firelighting techniques.
I notice throughout your reply you use American spellings!
Colin Huller
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Figure Stone
prep01 wrote:
Marcasite / Pyrite is a very common find on many an Archaeological site as it was used to start fires.(with flint),  I am often asked for and supply Marcasite nodules for ancient firelighting techniques.
I notice throughout your reply you use American spellings!


You'd be lucky to get any correct spellings from me as Im dyslectic, perhaps your noticing my underlined corrections, as I use whatever dictionary this computer has and have to correct often. Many of my flint finds have strike marks, and even etching marks done in pyrite, paleolithic people were much more artistic than the mainstream suggests, it's quite obvious if you think about it, people didn't suddenly become capable of the amazing cave art of Lascaux etc. The echinoid, looks like it has some modification, has possible figuration, and a very usefull cutting edge, so almost an all in one for a paleolithic person.
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nomadiclifeguide
Thanks for the info, i understand it but i aint buying it sorry.
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Figure Stone
That's fine, some people still believe in a flat earth.
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MadMatt
is there a point to all of this ???? yes or no will do
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Figure Stone
Yes, I posted a very rare pyritsed fossil, I found in on a prehistoric site, nomadiclifguide was interested in my research.
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prep01
Assumring the echinoid is wholey composed of Pyrite - please measure its specific gravity.
Colin Huller
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Figure Stone
prep01 wrote:
Assumring the echinoid is wholey composed of Pyrite - please measure its specific gravity.


I will have a go, but I don't think I have something very accurate to measure the water displacement volume, although I guess i could weigh the displaced water as well to gets it's volume. it Does feel like solid pyrite. And I just realized what you were on about with the American spelling, the Article was published in an American archeological magazine, the editor had me correct spellings and grammar, and then I re-posted the corrected version to my blog.
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Figure Stone
My method was very improvised, but here are the results anyway:
Fossil weighs 100g
Water displaced weighs 27g so 27ml displaced.
100/27 = 3.7 is the specific gravity of the fossil.
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s.c.


A google search provides no other samples of  pyritised echonoids, so it's not just you, it appears to be a very rare find.


I have pyritised echinoids from Sheppey, a location where there are also many pyritised gastropod, bivalve, teredo burrow etc. fossils. I see no reason why echinoid casts shouldn't be found pyritised in the same way as other marine invertebrates.  There may simply be fewer due to bias in the fossil record.

Sam
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prep01
Figure Stone, this is not fully pyritised as the specific gravity for FeS2 is 4.9 - 5.2 (+_ 0.1).
Colin Huller
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