To Be?

[CreekCrawler]

Greetings from the eagle ford! I came across this piece of carapace from either a 3 toed box turtle or an ornate. It looks kinda light in color compared to what I deem to be fossilized. Any input from members will be greatly appreciated! I'll post two pics one of the find and one of a recent box turtle demise.

thanks

B

[CreekCrawler]

Greetings from the eagle ford! I came across this piece of carapace from either a 3 toed box turtle or an ornate. It looks kinda light in color compared to what I deem to be fossilized. Any input from members will be greatly appreciated! I'll post two pics one of the find and one of a recent box turtle demise.

thanks

B

The other 1

[Shuko]

Note: don't try this until at least two other members confirm it, and you research it on Google first!

I've heard that if you try to burn a fossil with a lighter, it won't smell, but if you burn a modern bone with a lighter, it smells like burning hair. o.o That's one way to tell.

Also, try tapping it lightly with a rock. If it makes a clacking sound instead of a light tap, it could be mineralized, and therefore a fossil.

These are two methods I've heard of. Dunno if they're true or not.

[Gatorman]

Hitting a fossil is bad. the match test works well but make sure to use a match not a lighter some lighters burn very very hot.

[Harry Pristis]

Hitting a fossil is bad. the match test works well but make sure to use a match not a lighter some lighters burn very very hot.

What's wrong with giving a fossil a hit, Anson? I do it all the time with petrified wood -- give it the old 'clank' test. Would I do that with different fossils like clanking say two carnivore jaws together? No. Two 'gator osteoderms? Yes.

What is wrong with a very, very hot flame for the scorch test? If the bone is mineralized, the soot-free butane flame won't damage the fossil. If it's not mineralized . . . well, probably no great loss to have a faint scorch-mark on the bone. Bones from the river typically are dark-colored in either case. You always want to run any potentially-destructive test on an inconspicuous spot.

What is your experience, Anson, that you recommend against using a butane lighter? Have you been setting fire to bones?? In that case, you may be an osteopyromaniac.

-------Harry Pristis

[CreekCrawler]

Ok, I tried the match and there is a faint smell of hair. Very faint though! Also I tried to wipe the scorch mark off the backside and a small piece came off! That was after I banged it with a rock a few times for good measure LOL

[emtilt]

What is wrong with a very, very hot flame for the scorch test?

It can crack thin or fragile fossils due to the rapid temperature change. A match flame peaks at 600 to 800 degrees Celsius (though this varies wildly, and for some matches, like large wood ones, it might be closer to what butane burns at), while butane can reach 2000 degrees Celsius. The practical values would be significantly lower than this, due to heat dissipation and less-than-ideal burning conditions. Rapid temperature change will stress any material.

[Gatorman]

It can crack thin or fragile fossils due to the rapid temperature change. A match flame peaks at 600 to 800 degrees Celsius (though this varies wildly, and for some matches, like large wood ones, it might be closer to what butane burns at), while butane can reach 2000 degrees Celsius. The practical values would be significantly lower than this, due to heat dissipation and less-than-ideal burning conditions. Rapid temperature change will stress any material.

Thank You

[Bill]

"What's wrong with giving a fossil a hit, Anson"?

-------

It depends on what the fossil is.

Hitting two Calcite ammo's together, for example, or hitting one with your hammer, etc, would certainly damage it. A lot of other fossils would receive damage if hit too.

[Harry Pristis]

...while butane can reach 2000 degrees Celsius. The practical values would be significantly lower than this, due to heat dissipation and less-than-ideal burning conditions. Rapid temperature change will stress any material.

You guys sound like a fussy grandma warning against the evils of rock and roll! LOL The experience is different from the theorizing. Emtilt seems to recognize this when he refers to "the practical values."

Keep in mind that you are not trying to set fire to a bone (combustion); you are merely trying to pyrolize a bit of the organic somponents (principally collagen). Pyrolysis occurs at much lower temperatures than combustion. Thermal shock is not a practical worry when dealing with this minimal heating of bone.

PYROLYSIS: The breaking down of materials by heat, whatever the source, to yield volatiles and charcoal

VOLATILES: The vapor and gas that emerges from the biomass, largely between 200 and 400°C.

You, the experimenter, must always use good judgement and be in control of your experiment. Trust your experience, not what you think must be the case. If you don't have experience with this scorch test, acquire some. There is nothing like learning by doing.

-------Harry Pristis

[emtilt]

Err, I've seen small fossils crack under such a test. The heating is not minimal; you are applying a high heat to a comparatively small region of the specimen, and then rapidly cooling it again, so you have massive temperature differentials over tiny regions. This clearly isn't an issue with larger, tougher fossils like big bone segments, but it certainly is for small ones with thin, fragile areas. It has nothing to do with scorching or combustion, it's just a byproduct of the differential heating.

[tomclark]

Fairly recently dead turtle boom. Not fossil IMHOP

[Harry Pristis]

Err, I've seen small fossils crack under such a test. <snip>

Oh, really? Which fossils were those, emtilt?

[emtilt]

Hasn't happened in a long time, but the last time was a small, light bone that I never positively identified but think might be bird. It came from the Steinhatchee river. The larger end has the articulating surfaces and it is broken on the narrow end. It wasn't intact when I found it, but it had a bit more on the broken side. I put flame to it there to be sure it was fossil, and it cracked brittlely. It's a rather airy bone, and pretty small, but certainly fossil. I really wonder why you are so incredulous about this rather mundane issue.

[Harry Pristis]

Hasn't happened in a long time, but the last time was a small, light bone that I never positively identified but think might be bird. It came from the Steinhatchee river. The larger end has the articulating surfaces and it is broken on the narrow end. It wasn't intact when I found it, but it had a bit more on the broken side. I put flame to it there to be sure it was fossil, and it cracked brittlely. It's a rather airy bone, and pretty small, but certainly fossil. I really wonder why you are so incredulous about this rather mundane issue.

I think it is important to give examples from our experience to illustrate our arguments. It's just good pedagogy.

You argued without specifying an example that, "It [a flame] can crack thin or fragile fossils due to the rapid temperature change.

I argued that, "You, the experimenter, must always use good judgement and be in control of your experiment."

We're both correct. The lesson from your experience may be that we should use the scorch test only on the thick end of a bird bone, OR that the scorch test is too risky with bird bones, OR that the 'clank' test is more appropriate for tiny, fragile bones.

Readers here can take their own lesson from this more-complete airing of our experience.

-------Harry Pristis

[PaleoRon]

One safe way to do the "burn" test is to hold a large needle in pliars and heat the needle to red or white hot and then touch it to an inconspicuous area of the fossil.

[Auspex]

Occasionally, I'll gently tap a suspect bone on a front tooth. It's very tactile, and a petrified bone will feel (and sound) stony. Non mineralized bones don't "ring"; they feel dead. Try it a few times with material of known composition (both petrified and not); you'll see what I mean, and develop a feel for what is or isn't fossil.

(P.S. If it's a river find, you might want to wash it first...)

[Guest solius symbiosus]

I think it is important to give examples from our experience to illustrate our arguments. It's just good pedagogy.

You argued without specifying an example that, "It [a flame] can crack thin or fragile fossils due to the rapid temperature change.

I argued that, "You, the experimenter, must always use good judgement and be in control of your experiment."

We're both correct. The lesson from your experience may be that we should use the scorch test only on the thick end of a bird bone, OR that the scorch test is too risky with bird bones, OR that the 'clank' test is more appropriate for tiny, fragile bones.

Readers here can take their own lesson from this more-complete airing of our experience.

-------Harry Pristis

Perhaps, I have found a way to remove the coal from my Lepidodendron.

[Harry Pristis]

Occasionally, I'll gently tap a suspect bone on a front tooth. It's very tactile, and a petrified bone will feel (and sound) stony. Non mineralized bones don't "ring"; they feel dead. Try it a few times with material of known composition (both petrified and not); you'll see what I mean, and develop a feel for what is or isn't fossil.

(P.S. If it's a river find, you might want to wash it first...)

That's great, Auspex -- a new variation on the 'clank' test to use on the most fragile fossils.

I tried your tooth-test on a bird bone here just for fun. I know this bone is not fully mineralized, and I can report that gently tapping it against my tooth produced a 'clack' rather than a 'clank.'

This bone is an ulna with papillae for feather attachment. It's probably from a large wading bird such as a heron or ibis, or it could be from a crane. It is only a few thousand years old, from a well-known site.

This is one bone on which I would not be tempted to use the scorch test.

--------Harry Pristis

[Guest michael]

dont try eather one if it is not a fossil tooth bone it wall be white or most are if it dark bronw or black it fossil

[Auspex]

This bone is an ulna with papillae for feather attachment. It's probably from a large wading bird such as a heron or ibis, or it could be from a crane. It is only a few thousand years old, from a well-known site.

--------Harry Pristis

Nice artifact! As a guess (after cursory examination and extrapolating length from relative girth), maybe large heron/egret, maybe Sandhill Crane (too slender for Whooping), or maybe Wood Stork. Again, I think bone tool artifacts are very cool!