Non-fossils

[Still_human]

Are any of those mammoth "fossils" around actually fossils? Wouldn't they still be natural bone? I know that the remains found in colder northern area, the remains are still original dead tissue, because they're regularly found with soft tissue and hair, but they're found other places too, along with all other animals from the more recent periods, where freezing isn't a factor, but Is there even enough time for fossilization to occur for those animals? Is there a general point in, or period of time, after which it's just not old enough for fossilization to occur? I know any such point, or period, would vary depending on the regions environmental conditions, but I would imagine there are places where there is such a point before which geologically, remains are fossilized, and after which remains are still actual bone.

[Ludwigia]

As far as I understand it, anything over 10,000 years old is regarded as a fossil. Anything younger than that would be called a mummy I suppose.

[DPS Ammonite]

Lugwigia is right; a fossil is defined as being over 10,000 years.

 

You are also asking another question: how long does it take for a fossil/ prefossil to become mineralized? The answer is that it depends: anywhere from a few years to millions of years. Research suggests that wood can petrify completely in a few decades. Some calcite shells are nearly unchanged after millions of years.

 

There is no exact answer to how long it takes to mineralized a bone. Well mineralized bones of less that a thousand years are rare while unmineralized bones millions of years old are also rare.

[Still_human]

On 12/15/2018 at 3:50 AM, Ludwigia said:

As far as I understand it, anything over 10,000 years old is regarded as a fossil. Anything younger than that would be called a mummy I suppose.

 

On 12/15/2018 at 4:03 AM, DPS Ammonite said:

Lugwigia is right; a fossil is defined as being over 10,000 years.

 

You are also asking another question: how long does it take for a fossil/ prefossil to become mineralized? The answer is that it depends: anywhere from a few years to millions of years. Research suggests that wood can petrify completely in a few decades. Some calcite shells are nearly unchanged after millions of years.

 

There is no exact answer to how long it takes to mineralized a bone. Well mineralized bones of less that a thousand years are rare while unmineralized bones millions of years old are also rare.

WOW!!! You guys just blew my mind!!! You totally upturned my entire idea of a fossil! Not only is that crazy to me cause I'm just so surprised, it's crazy to me because it seems so....silly! Of course I'm bias because it's been my entire understanding of what a fossil is until right now, and it's hard to suddenly accept such a huge change, but i also feel like mineralization is a much better definition for a fossil than just a time period. That means a frozen animal with skin and a brain, and other internal organs can be a fossil....that's such a strange idea. Maybe I'll feel differently once the idea has had time to sink in, but right now it seems so arbitrary and pointless this way. Are there any scientific reasonings behind the 10,000year rule that I'm not getting yet, or IS it actually just a completely arbitrary rule?

[Harry Pristis]

10,000 years is completely arbitrary, as far as I know.

 

There seems to be endless misunderstanding about the term "fossilized."

"Fossilized" (along with "petrified") is a near meaningless term in this specialized forum. The term is often substituted for "mineralized" in describing a bone or tooth. But, fossilized doesn't always equate to mineralized because many fossils are not reinforced or replaced by minerals.

Bone is primarily composed of hydroxyapatite and collagen. Hydroxyapatite is an inorganic compound of calcium, phosphate, and hydroxide which is organized in a crystal latticework that gives bone (and teeth) structural rigidity. It preserves well as a fossil under some conditions.

Collagen is a fiberous protein that serves as connective tissue in bones and muscles. It does not preserve well in a fossil. As collagen decomposes, it may be replaced in the hydroxyapatite latticework by minerals from the depositional environment (e.g. silica dioxide dissolved in groundwater).

Bone reinforced with exogenous minerals is said to be "mineralized." If the bone components (including the hydroxyapatite) are entirely replaced by exogenous minerals such as silica, it is said to be "replaced by -". If a bone is mineralized, it is more likely to be a fossil. If a bone is not mineralized, it is less likely to be a fossil. No absolutes, only likelihoods, because there are exceptions.

In the case of leaves and wood, as with bones, permineralization depends on the circulation of mineral-saturated groundwater. If there is limited or no circulation (or no suitable minerals in solution), then there is no permineralization. BUT, the organic remains - the leaves, or wood, or bone - are still fossils ("fossilized" if you like).

A 'burn test' or 'match test' will indicate only whether there is collagen remaining in a bone -- scorched collagen has an awful smell. Briefly apply an open flame (I prefer a butane lighter) to an inconspicuous area of the object . . . you cannot keep a pin hot enough long enough to scorch collagen. Tooth enamel contains hydroxyapatite, but doesn't contain significant collagen, so the 'burn test' on tooth enamel would be a waste of time.

The 'click test' - tapping a putative fossil against your teeth - was a joke that caught on. There are plenty of other things in the environment against which you can click a bone. Don't put the remains of dead, decomposed animals in your mouth.

 

I apologize for posting this as often as I do, but it seems warranted in this case.

 

 

[Ludwigia]

I'm just passing along what is generally accepted. It is to a certain extent an arbitrary choice of time frame, but this assumption is based among other things on the proven fact that it takes about that long for most organic material to become inorganic. The matter is of course complicated by the fact, as you mention, that some buried remains which are older than 10,000 years still retain a lot of organic substance. This is the reason why one often speaks in such cases of subfossils.

[ynot]

All of this is why I like "lithified life".

[Harry Pristis]

Here's what Bobby said on researchgate.net four years ago:

Robert W Boessenecker

College of Charleston

In my opinion, the only non-subjective criteria to identify what is fossil and what is not is whether or not it has been naturally buried. The problem with subfossil is that it's an arbitray cutoff - anything from the Pleistocene is a fossil, while something from the earliest Holocene is somehow magically a subfossil. Diagenesis also doesn't work, as a lot of Pleistocene fossils have not really undergone much diagenetic alteration. This means many specimens from the Pleistocene would not count as fossils - which, from a standpoint of consistency is fine, but unconventional due to the perception of certain Pleistocene material as non-fossilized and impractical on the grounds that some sort of time-intensive test for diagenetic alteration is needed to even tell you if you have a fossil.

Ironically, identifying a golden retriever who went missing on a camping trip and whose skeleton was naturally buried in a river bank last August as a fossil seems just as unconventional (even though from a taphonomist's perspective, what I think to be most correct), so perhaps the fossil/subfossil convention for Pre-Holocene/Holocene remains is perhaps the best (and most widespread in use).

[doushantuo]

tangentially relevant?

 

 

[Ludwigia]

23 hours ago, Harry Pristis said:

Here's what Bobby said on researchgate.net four years ago:

Robert W Boessenecker

College of Charleston

In my opinion, the only non-subjective criteria to identify what is fossil and what is not is whether or not it has been naturally buried. The problem with subfossil is that it's an arbitray cutoff - anything from the Pleistocene is a fossil, while something from the earliest Holocene is somehow magically a subfossil. Diagenesis also doesn't work, as a lot of Pleistocene fossils have not really undergone much diagenetic alteration. This means many specimens from the Pleistocene would not count as fossils - which, from a standpoint of consistency is fine, but unconventional due to the perception of certain Pleistocene material as non-fossilized and impractical on the grounds that some sort of time-intensive test for diagenetic alteration is needed to even tell you if you have a fossil.

Ironically, identifying a golden retriever who went missing on a camping trip and whose skeleton was naturally buried in a river bank last August as a fossil seems just as unconventional (even though from a taphonomist's perspective, what I think to be most correct), so perhaps the fossil/subfossil convention for Pre-Holocene/Holocene remains is perhaps the best (and most widspread in use).

Which of the many articles linked here are you referring to?

[Ludwigia]

2 hours ago, doushantuo said:

tangentially relevant?

 

 

The link doesn't work for me.

[doushantuo]

and this one will ,I hope

[DPS Ammonite]

There is a problem viewing Harry Pristis’ post past the third line (after Boessenecker). Supposedly there is white lettering on a white background.

 

It is slightly visible when Ludwigia quoted Harry’s post: white lettering on a very light gray background. 

 

Hopfully we we can resolve the problem.

[Ludwigia]

20 minutes ago, doushantuo said:

and this one will ,I hope

Yes it did, thank you.

[Ludwigia]

13 minutes ago, DPS Ammonite said:

There is a problem viewing Harry Pristis’ post past the third line (after Boessenecker). Supposedly there is white lettering on a white background.

 

It is slightly visible when Ludwigia quoted Harry’s post: white lettering on a very light gray background. 

 

Hopfully we we can resolve the problem.

 

I just barely managed to read it and agree with Robert's points of view. Thanks for pointing this out.

 

[DPS Ammonite]

Here is what Harry Pristis said (pasted as plain text and quotes added).

 

 

Here's what Bobby said on researchgate.net four years ago:

Robert W Boessenecker

College of Charleston

“In my opinion, the only non-subjective criteria to identify what is fossil and what is not is whether or not it has been naturally buried. The problem with subfossil is that it's an arbitray cutoff - anything from the Pleistocene is a fossil, while something from the earliest Holocene is somehow magically a subfossil. Diagenesis also doesn't work, as a lot of Pleistocene fossils have not really undergone much diagenetic alteration. This means many specimens from the Pleistocene would not count as fossils - which, from a standpoint of consistency is fine, but unconventional due to the perception of certain Pleistocene material as non-fossilized and impractical on the grounds that some sort of time-intensive test for diagenetic alteration is needed to even tell you if you have a fossil.

Ironically, identifying a golden retriever who went missing on a camping trip and whose skeleton was naturally buried in a river bank last August as a fossil seems just as unconventional (even though from a taphonomist's perspective, what I think to be most correct), so perhaps the fossil/subfossil convention for Pre-Holocene/Holocene remains is perhaps the best (and most widspread in use).”

[DPS Ammonite]

5 minutes ago, DPS Ammonite said:

Here is what Harry Pristis said (pasted as plain text and quotes added).

 

 

Here's what Bobby said on researchgate.net four years ago:

Robert W Boessenecker

College of Charleston

“In my opinion, the only non-subjective criteria to identify what is fossil and what is not is whether or not it has been naturally buried. 

@Boesse

 

I wonder what is meant by “naturally buried”? Does that mean that a 20,000 year old mineralized human skeleton buried by another human is not a fossil? Are humans part of the natural process; some say that they are.

 

Are 200 year old leaf impressions in travertine deposited by Havasu or Fossil Creeks in Arizona also fossils by this definition?

[DPS Ammonite]

13 hours ago, Harry Pristis said:

10,000 years is completely arbitrary, as far as I know.

 

There seems to be endless misunderstanding about the term "fossilized."

"Fossilized" (along with "petrified") is a near meaningless term in this specialized forum. The term is often substituted for "mineralized" in describing a bone or tooth. But, fossilized doesn't always equate to mineralized because many fossils are not reinforced or replaced by minerals.

Bone is primarily composed of hydroxyapatite and collagen. Hydroxyapatite is an inorganic compound of calcium, phosphate, and hydroxide which is organized in a crystal latticework that gives bone (and teeth) structural rigidity. It preserves well as a fossil under some conditions.

Collagen is a fiberous protein that serves as connective tissue in bones and muscles. It does not preserve well in a fossil. As collagen decomposes, it may be replaced in the hydroxyapatite latticework by minerals from the depositional environment (e.g. silica dioxide dissolved in groundwater).

Bone reinforced with exogenous minerals is said to be "mineralized." If the bone components (including the hydroxyapatite) are entirely replaced by exogenous minerals such as silica, it is said to be "replaced by -". If a bone is mineralized, it is more likely to be a fossil. If a bone is not mineralized, it is less likely to be a fossil. No absolutes, only likelihoods, because there are exceptions.

In the case of leaves and wood, as with bones, permineralization depends on the circulation of mineral-saturated groundwater. If there is limited or no circulation (or no suitable minerals in solution), then there is no permineralization. BUT, the organic remains - the leaves, or wood, or bone - are still fossils ("fossilized" if you like).

A 'burn test' or 'match test' will indicate only whether there is collagen remaining in a bone -- scorched collagen has an awful smell. Briefly apply an open flame (I prefer a butane lighter) to an inconspicuous area of the object . . . you cannot keep a pin hot enough long enough to scorch collagen. Tooth enamel contains hydroxyapatite, but doesn't contain significant collagen, so the 'burn test' on tooth enamel would be a waste of time.

The 'click test' - tapping a putative fossil against your teeth - was a joke that caught on. There are plenty of other things in the environment against which you can click a bone. Don't put the remains of dead, decomposed animals in your mouth.

 

I apologize for posting this as often as I do, but it seems warranted in this case.

 

 

 

Here is an almost readable copy of what Harry said. Hopefully @Fossildude19 can improve it.

Edited December 25, 2018 by Kane
Changed font colour

[Johannes]

Differentiation beween "fossil" and "recent" can be difficult and is (liek evereything in science) only a question of the definition you use (which can and should be scrutinized everytime, like science should be). So, "fossil" can depend on process of burying, state of mineralization, and so on.

 

The easiest definition is, in my opinion, to follow the earth timne scale (like widely accepted among palaeontologists and people who have to deal with earth history). In this definition, fossils are dead* organsims from times older than the P/H-Boundary. Everything from the holocene is, accordingly, recent. Biologists didn't like this, so they launch the terms "subfossil" and "subrecent", both terms which are handy crutches.

 

Following this definition is the scientifically most practical way, but for sure not a perfect agreement.

 

Merry recent christmas to all of you!

 

 

*there are/might be some living organsims older than the P/H-Boundary, making this issue not easier, again.

 

[ynot]

14 hours ago, ynot said:

All of this is why I like "lithified life".

I am liking this term a lot more since reading all the confusion associated with all the other terms for a fossil or not.

 

[Harry Pristis]

I don't know what the problem was with my post.  Every post in this thread is perfectly presented on my laptop.  Happy Holidays!

 

 

[Boesse]

I stand by my preferred definition. The definition of "fossil" should be process-based, NOT based upon age - but concede that "subfossil" is an acceptable (if 100% arbitrary and mostly meaningless, if reserved for Holocene specimens only) term.

[Johannes]

12 minutes ago, Boesse said:

 100% arbitrary and mostly meaningless, if reserved for Holocene specimens only

I did completly agree! But sometimes it might be more comfortable (or better for PR) to speak about "subfossil" organisms, or to find a compromise, knowing about the weak points in both of the definitions we like to use.

 

For me the P/H-Definition is better, because: echinoderms start with mineralization of the inner skeleton soon after death (hours), mineralization of soft tissue in special environments sometimes after seconds (e.g. Cretaceous of Araripe, Pleistocene concretions near Greenland, but in lab-experiments, too). So, defining "fossil" at a special time of mineralization process is can be hard to point, whereas and abstract date (P/H-Boundary) might be easier to use in communication.

 

I completly understand your path of argumenation, and can understand the "pro's" of your way, too. Please do not feel hesitated by my arguments.

 

 

[Harry Pristis]

 

Here's a Florida tapir radius with human-produced cut marks.  Tapirs are part of the Pleistocene megafauna of Florida.  The bone is well-mineralized.  We know that Native Americans lived in Florida from as early as 11,000 years, but their traces are few.  More abundant are the traces of Late Paleo-Early Archaic inhabitants.  Let's assign an arbitrary date of 9 Ka to this tapir bone.  Is the bone a fossil or a subfossil?  (Calling it simply "an artifact" is a cop-out.)

 

 

[erose]

Mineralization is not what identifies something as a fossil. And the 10,000 year mark is totally arbitrary. 10 paleontologists will give you ten different answers.  There is a place here in Texas where we collect Eocene fossils that are, from what I understand, still original shell. That's around 45 million years old. The counterpoint might be some really cool mineralized Malachite timbers from a 2000 year old Greek copper mine. I think they would qualify as "petrified wood" but not as fossil wood. And what about ichno fossils? Those dino prints are not just "geological" in origin even if they are, in fact, nothing more than displaced mud. 

 

Google the definition of fossil. You will find many definitions. Bt the main theme is that they are biological in origin and they are "old". The "how old" question is up for debate.  But despite the fact that some of the dictionary definitions use the term 'petrified" you would not get a paleontologist to agree that a fossil has to be petrified.