The explanation of fossilization usually goes along these lines, minerals replaced the bone and became rock. But, the amazing detail of some fossils seems to indicate some of the original organic material has been preserved. Is this true?

All organic material decays, hence I don't believe you can find it left over in fossils. The only method is to find an animal stuck in sap or something.

What about the blood they apparently found inside fossilized dino bones?

Didn't they find bone marrow of Wolly Mamoths?
Perhaps it is a distinction between "fossil" and "preserved specimen"?

What about the blood they apparently found inside fossilized dino bones?

I've not heard of that, nor do I think it's even possible. Do you have a link that discusses it?

http://www.newscientist.com/channel/life/dinosaurs/dn7195-blood-vessels-recovered-from-it-rexi-bone.html

http://www.newscientist.com/channel/life/dinosaurs/dn7195-blood-vessels-recovered-from-it-rexi-bone.html

That was very interesting - thank you! :)

It has been thought that all organic material is replaced, but evidently not.

they have found bits and pieces of dinosaur dna

They have found proteins and such in fossils of one-celled beings - "protists" - from many millions of years ago, fairly routinely.

Sorry I don't have a link, my latest reminder of that was from a side comment in the science section of the the NYT (Tuesdays), in an article about the collagen and other proteins found in some fossils of Tyrannosaurus bones. The guy was pointing out that there was every reason to be hopeful in investigating the fossils of larger animals, and he was surprised the matter hadn't come up before.

Didn't they find bone marrow of Wolly Mamoths?
Perhaps it is a distinction between "fossil" and "preserved specimen"?

Nearly intact Mammoth remains have been found frozen in the arctic permafrost.
Mammoths completely died out only around 10,000 years ago, so the chances of them being preserved is much greater.
I think I may have some things in my freezer that are almost that old.

Hmm...mammoth DNA. I wonder how long it will be before an elephant gives birth to one. There's gonna be some lab out there somewhere that tries it.

I don't know how I feel about that. If man wiped them out, try bringing them back. If they died due to natural selection, so sad too bad.

Would you hesitate to return a species from near extinction, say if there were only a couple left? Then why would you not want to return an extinct species? Well, with dinosaurs you probably have a point considering their ferocity. But, wooly mamouths aren't going to harm us.

http://www.flickr.com/photos/80066534@N00/42958127/ = mammoth

We don't make history, we change history.:shrug:

Would you hesitate to return a species from near extinction, say if there were only a couple left? Then why would you not want to return an extinct species? Well, with dinosaurs you probably have a point considering their ferocity. But, wooly mamouths aren't going to harm us.

I can certainly see a time when scientists do manage to resurrect extinct species, if only for study purposes. However, there are not enough forests left in the right places to sustain woolly mammoths, so I can't envisage herds of them in the wild and also, how do you know they are safe?

I'm assuming wooly mammoths are like elephants, which are relatively safe.

From what I understand, complex organic molecules such as DNA are not very stable once the living organism dies.
Sure we can find segments, but their would not be enough information to successfully 'clone'.

Original article by Jack Horner and his research teams: "Soft-tissue vessels and cellular preservation in Tyrannosaurus rex." http://www.sciencemag.org/cgi/content/abstract/307/5717/1952
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=15790853&dopt=Abstract

This article used to be free. I do have the article downloaded and pics that I could post if you're really into this but I don't have a lot of time.

Hmm...mammoth DNA. I wonder how long it will be before an elephant gives birth to one. There's gonna be some lab out there somewhere that tries it.I've seen bits and pieces in the popular press indicating that this idea is under consideration.I don't know how I feel about that. If man wiped them out, try bringing them back. If they died due to natural selection, so sad too bad.It's one thing to bring back a virus that will be difficult to control. I don't see anything wrong with setting up a mammoth preserve in an underpopulated place in Siberia. It would boost the local economy with tourism.

As for whose fault it is... We may never be able to bring back the moa, dodo or Tasmanian wolf. So maybe we'll get some cosmic brownie points for bringing back one that wasn't our fault. :)

From Petrified Forest National Park website, www.nps.gov/pefo, where I volunteered for several months....
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Questions Commonly Asked about Petrified Wood

Why do some of the petrified logs look like “real wood”? In some cases the wood has not been completely agatized. The “woody” structure has been preserved and the fossilization process is called, “permineralization.” When a small chip is dissolved in hydrofluoric acid, a small percent of lignin is still observed with biologic staining.

What happened to the roots, branches, bark, and cones from the trees? None have been found physically attached to the logs. However, we do have preserved leaves and reproductive structures which indicate that the trees may belong to the genus Araucarioxylon. We have a single preserved specimen with bark from the entire park. When a tree dies, the bark falls off quickly because it is only held on by a thin membrane called the cambium. Leaves, needles, and blades fall off as well. Roots, branches, and remaining bark are knocked off by transportation in waterways.

Why do some logs have “holes” in them? Some of the open spaces are due to decomposition before petrification began. Also, as in forests today, some logs may be hollow naturally.

Is petrified wood good for anything? It is used as a semi-precious gemstone in jewelry and as an ornamental stone in book ends, clocks, furniture, etc. Petrified wood is valuable scientifically since it tells us there have been trees on Earth for a very long time. It also allows us to create a climatic reconstruction of the Triassic Period.

How heavy is petrified wood? It depends on the chemistry - agatization vs. permineralization. On average the petrified wood is about 150 pounds per cubic foot.

How hard is petrified wood? Very hard. Petrified wood rates between 7 and 8 on Moh’s Hardness Scale. Only topaz, corundum (ruby and sapphire), and diamonds are harder.

What thickness of the Chinle Formation contains the fossilized wood, plants, reptiles, amphibians, etc? The Chinle Formation in the park is approximately 600 meters thick. This formation contains fossils throughout.

How long does it take wood to petrify? Probably less than 100 years. These logs were petrified during the Upper Triassic and have remained so until the present. The organic matter needs to turn to stone before it rots completely.

Will petrified wood ever decompose? Petrified wood does not decompose or decay. It will physically disintegrate through weathering and erosion, just like any rock.

Is the petrification process taking place today? Anywhere organic matter buried by rivers, lakes, and oceans is found with dissolved silica, petrification may be occurring.

Has amber ever been found in the park? Yes. This fossil resin is hard, brittle, and once exposed, breaks down rapidly.

Why did these trees turn to stone and not coal? The geologic conditions were not right for coal. Depth of burial of organic matter responds to elevated pressure and high temperatures for coal.

Do the petrified logs provide homes for any of the desert wildlife? Yes. Birds, mice, and insects live or nest in the hollow openings. Snakes and lizards live under them.

Is there any petrified wood or plant material in the park that is carbonaceous, charcoalified, or coalified? In the Tepees area there are layers of plant material turned to a black carbon residue. Several localities in the park contain minor amounts of what appears to be charcoalified wood (calcium carbonate). No true coalified wood has been found in the park. This requires pressure and high temperatures.

What will it cost me to have my own piece of petrified wood cut and polished? According to Jim Gray, of the Petrified Wood Company, the going industrial price [2004] is approximately $1.00 per square inch cut and polished. Contour polishing is much more expensive and requires more man hours. A 12 inch in diameter piece may cost as much as $300, according to Chuck Scott of the Rock Factory.

Did the logs shrink or expand as they were petrified? No, the size of the logs today is most likely the size of the logs before petrification.