Since We Are Talking Aurora...

[Harry Pristis]

Here are some papers and abstracts that you should read (these are not restricted to phosphate alteration through diagenesis):

Rao et al. 2008. Miocene phosphorites from the Murray Ridge, northwestern Arabian Sea. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 260, no. 3-4, pp.347-358

Martill, D. M. 1991. Bones as stones: The contribution of vertebrate remains to the lithologic record. pp. 270–292 in S. K. Donovan (ed.), The Processes of Fossilization. Columbia Universtity Press, New York.

Jacque et al. 2008. Implications of diagenesis for the isotopic analysis of upper Miocene large mammalian herbivore tooth enamel from Chad. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 266, no. 3-4, pp.200-210

Trueman et al. 2008. Why do crystallinity values fail to predict the extent of diagenetic alteration of bone mineral? Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 266, no. 3-4, pp.160-167

Pasteris and Ding, 2006. Fluoridation of a fossil horse tooth from the "pre-Colgate era". Abstracts with Programs - Geological Society of America, vol.38, no.7, pp.46, Oct 2006

Harwood et al. 2005. A comparative study of authigenic mineralization and rare earth element geochemistry of vertebrate microfossil assemblages in the Campanian Judith River Formation of Montana. Geological Society of America, 2005 annual meeting, Salt Lake City, UT, United States, Oct. 16-19, 2005

Goodwin et al. 2007 Elemental composition and diagenetic alteration of dinosaur bone; distinguishing micron-scale spatial and compositional heterogeneity using PIXE. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 253, no. 3-4, pp.458-476, 27 Sep 2007

Viana et al. 1998. Preservation of biomineralized tissues of fishes from the Santana Formation (Lower Cretaceous of the Araripe Basin, NE-Brazil). Estudos Tecnologicos, vol.21, no.46-47, pp.91-100

There were hundreds of other hits on georefs for this sort of stuff - it's taphonomy 101. Fossilized bone changes chemically, often involving phosphate minerals. I could have posted dozens of other articles as well, but I have actual things to do today, and dinner to eat.

Here are just a few from a cursory search of the literature. As far as lab tests, sure - that is the only real way to tell if something is phosphatized. OR SILICIFIED. Like toothpuller asks, how do you know your bones are silicified? Have you done the "lab test"?

In the case of rock units I was talking about, those were subjected to "lab tests" as you call them (see my above posts - petrographic/petrologic, SEM analysis, X-Ray diffraction). As were the bones in the studies I just mentioned - these had different chemical/mineral alterations not just due to phosphate recrystallization, but also to other chemical and mineral phases.

Also, give us an example of bones in-situ (associated with phosphorite deposits, per what I was talking about) that are blackened by a process other than phosphatization.

I don't understand how precipitation of phosphate minerals within the pore space of a bone is mechanical. That's still a chemical process, pure and simple. Unless of course you can explain how this can be 'mechanical' and not chemical. (FYI Merriam webster defines mechanical as: caused by, resulting from, or relating to a process that involves a purely physical as opposed to a chemical or biological change or process; And in fact I should mention that precipitation of any solid from a liquid, including the precipitation of phosphate within bone pores, is "Chemical Precipitation").

Lastly, most naturally occurring phosphate minerals contain more calcium than phosphate anyway, so that argument is pretty much a straw man.

Bobby

As I said, I don't think we need worry about what we're going call "all" mammal bones with diagenetically altered phosphate chemistry. You haven't been able to show us the first one yet.

Sooo . . . How will I identify a mammal bone with diagenetically altered phosphate chemistry if I find one here in Florida? Is it the black color? We know that lots of black mammal fossils are found without a significant association with phosphate, and lots of cream-colored mammal bones are found in the pebble phosphate in Florida and in the phosphate in NC and in the phosphate in North Africa. I guess it would take some lab testing, eh?

[Frank Menser]

I forgot...is this the ID forum?

It's just I posted some very nice pictures and well, I understand debating Phosphates can be fun, but....

[Boesse]

If you're not willing to read any of those papers, or at least the abstracts (which are freely available on the internet) then I'm not going to waste any of my time dickin around. All of those papers document what you don't want to accept.

In any event, you can't change someone's mind about something once they've already made it. I tried, and apparently the literature just isn't good enough. I know that you're wrong, and the literature states so; however, if you're going to ignore it, then this is a lost cause. Good luck to everyone else, I'm giving up on this one.

[Auspex]

OK, back to topic!

Here is my concern. NOT saying this is what it is, but The size, proportions and the curve of this fossil are much more similar to the sabres on the cat, than the tusks of the walrus.

Anybody know what the cross- or longitudinal-section of a cat sabre looks like?

There is something strange about the way this forum keeps coming and going on my computer. Anyone else having that problem?

Can you describe what's hapening, and when?

[Harry Pristis]

If you're not willing to read any of those papers, or at least the abstracts (which are freely available on the internet) then I'm not going to waste any of my time dickin around. All of those papers document what you don't want to accept.

In any event, you can't change someone's mind about something once they've already made it. I tried, and apparently the literature just isn't good enough. I know that you're wrong, and the literature states so; however, if you're going to ignore it, then this is a lost cause. Good luck to everyone else, I'm giving up on this one.

Bobby, calm down. I'm sorry that I've provoked such a dither. I don't really know what it is that you think I won't accept. What is it that I'm wrong about? I mean, literally, what assertion have I made that falls into the category of dogma?

I've asserted that Frank's find is a phosphate nodule, and I've asserted that one of your sentences was logically faulty. Other than those two assertions, I merely stated what is common knowledge about fossil mammal bone color.

Try to identify exactly what it is that we disagree about; state the difference in clear language; and then we'll resolve the problem.

[Frank Menser]

Auspex,

What is happening is that I post on a thread and sometimes it works, other times it takes hours or even a day to display. Sometimes they post and disappear. The same thing in the forum guide. I will click to it and it will have yesterday's posts but not today's.

Harry,

I appreciate your opinion on the "scute" that started this and while I enjoyed the conversation on Phosphates a second question came up about another piece I posted which has been called a walrus tusk but isn't). I really would appreciate your opinion on the item since I took a lot of extra pics of it.

[Guest N.AL.hunter]

On Sciencedaily.com they have an article about a fossil fish brain with this in it, "The mineralization of the brain is, according to the main author of the paper, Alan Pradel, from the MNHN, "due to the presence of bacteria that covered the brain shortly before decay and induced its phosphatization"". Just thought I'd throw this in here since it mentioned Phosphatization. Interesting article.

[Harry Pristis]

Auspex,

What is happening is that I post on a thread and sometimes it works, other times it takes hours or even a day to display. Sometimes they post and disappear. The same thing in the forum guide. I will click to it and it will have yesterday's posts but not today's.

Harry,

I appreciate your opinion on the "scute" that started this and while I enjoyed the conversation on Phosphates a second question came up about another piece I posted which has been called a walrus tusk but isn't). I really would appreciate your opinion on the item since I took a lot of extra pics of it.

Here's what I posted yesterday, Frank.

(PaleoRon @ Mar 3 2009, 02:27 PM)

The tusk frags that I found are not from a round tusk. They are flattened side to side and have an almost rectangular cross section. The fossil walrus tusks are different than the modern tusks.

"I agree with 'PaleoRon'. Walrus tusks, fossil or modern, are markedly flattened side-to-side. This fragment could easily be a section of walrus tusk."

[Auspex]

What is happening is that I post on a thread and sometimes it works, other times it takes hours or even a day to display. Sometimes they post and disappear. The same thing in the forum guide. I will click to it and it will have yesterday's posts but not today's.

I've never heard of anything like that before! I frequently hear of photo posting problems; sometimes the cause is oversize files (clearly, you don't have that problem), and sometimes just running a good disc clean-up does the trick. Are you running a PC or a Mac?

[Frank Menser]

Thanks Harry,

I saw that post, and the other on this forum where a walrus tusk just got IDed. I know that piece because Rmullen is my collecting buddy and I was there when he found it...which is why I took and posted the edge-on shots.

I have comparred it directly to the walrus at the Aurora Museum (pictured) and the "rectangular tusk with "flattened ends" is nothing like this. The dimensions of this are very Blade-like. If you observe the close up shot of the end you can see that more than 50% of the curve of outside of the piece is there and it is easy to project the rest of the shape of it.

I went into Frank Kocsis' book on Verts for the Neophytes and checked the comparison pics. The strirations on the walrus tusk (pg 75) do not match. Also at 1.75" way too thick.

What does compare favorably, is with the Smilodon gracilis photo on the next page. The height 1.25" and thickness; three 8ths of an inch are an exact match.

I am really hoping some of you guys show up at aurora for the fossil fest. I will have it there with me.

A. I have PC. I use CCleaner for laundry.

[tracer]

Personally, I prefer Sabre....

(Ok..I just edited this and everything I put here disppeared)

frank -

there was plenty of sabre witnessed in my impetuous yute, but i refused to participate. see, i saw some stuff that was pretty bad, even in foil fencing. when a cat and mouse game becomes cat and cat, things get ugly rapidly. one guy lunges and the other guy parry/lunges at the same time, and next thing you know, somebody's got a broken foil through their leg. but anyway, there was this guy, see, who dearly loved sabre, and his game was to try to hit people so hard on the top of the head that the sabre would bend around their mask and cut the back of their neck open. it was really sort of amazing to watch, but i decided i could learn vicariously without really needing to personally be one of the victims. seems like wherever you go, there are people like that, huh?

[Frank Menser]

frank -

there was plenty of sabre witnessed in my impetuous yute, but i refused to participate. see, i saw some stuff that was pretty bad, even in foil fencing. when a cat and mouse game becomes cat and cat, things get ugly rapidly. one guy lunges and the other guy parry/lunges at the same time, and next thing you know, somebody's got a broken foil through their leg. but anyway, there was this guy, see, who dearly loved sabre, and his game was to try to hit people so hard on the top of the head that the sabre would bend around their mask and cut the back of their neck open. it was really sort of amazing to watch, but i decided i could learn vicariously without really needing to personally be one of the victims. seems like wherever you go, there are people like that, huh?

The difference between a sport and an outlet for a violent nature(?)

My favorite opponent is my wife. at 4' 10" she has the uncanny ability to get under my 6' 4" guard. Sabre done right is more than just an excuse for schish kabob.

[Harry Pristis]

Thanks Harry,

I saw that post, and the other on this forum where a walrus tusk just got IDed. I know that piece because Rmullen is my collecting buddy and I was there when he found it...which is why I took and posted the edge-on shots.

I have comparred it directly to the walrus at the Aurora Museum (pictured) and the "rectangular tusk with "flattened ends" is nothing like this. The dimensions of this are very Blade-like. If you observe the close up shot of the end you can see that more than 50% of the curve of outside of the piece is there and it is easy to project the rest of the shape of it.

I went into Frank Kocsis' book on Verts for the Neophytes and checked the comparison pics. The strirations on the walrus tusk (pg 75) do not match. Also at 1.75" way too thick.

What does compare favorably, is with the Smilodon gracilis photo on the next page. The height 1.25" and thickness; three 8ths of an inch are an exact match.

I am really hoping some of you guys show up at aurora for the fossil fest. I will have it there with me.

A. I have PC. I use CCleaner for laundry.

The end shot does make the piece seem very slender for walrus. Cat sabers are serrated -- any evidence of serrations?

[Frank Menser]

Harry,

We have a few cats here so I knew what you were asking about. The bad news is this tooth was in the river too long. I took a jeweler's loup to it and there was none of the cutting edge surface that wasn't chiped. So I have to say inconclusive on that. My friend Ken Bader from the University of Kansas will be here in April to check it out.

It is very worn but the grain is similar to that on the sabre my wife is holding.

[Harry Pristis]

Harry,

We have a few cats here so I knew what you were asking about. The bad news is this tooth was in the river too long. I took a jeweler's loup to it and there was none of the cutting edge surface that wasn't chiped. So I have to say inconclusive on that. My friend Ken Bader from the University of Kansas will be here in April to check it out.

It is very worn but the grain is similar to that on the sabre my wife is holding.

That's an impressive group of cat skulls you have!

Here's a walrus tusk from the Alaska permafrost -- probably a female based on the size.

[Frank Menser]

That's an impressive group of cat skull you have!

Here's a walrus tusk from the Alaska permafrost -- probably a female based on the size.

Nice tusks! Thanks for showing. We have been checking photos and specimens and the curve on this piece is an exact match for Smilodon. have to admit, this is getting exciting.