Pomp

Off to Evo/Creation.

ps418

Um, fossils are collected at the earth's surface because that's the only place you can collect them, with the exception of small fossils such as plant spores and pollen, and marine plankton such as forams and radiolarians, that can be recovered from well cores.

Alas, it usally not practical to construct a deep open-pit mine to go fossil hunting.

Nor is it necessary, since you can often trace the body of rock you are interested in laterally to an outcrop, where it is exposed and can be sampled. For instance, in the Grand Canyon area the Permian Kaibab Limestone is exposed right at the surface. But as you trace it north and east, it is overlain by up to several thousand feet of younger sediments.

It is just plain bad logic to assume that because a fossil is x million years old and is located at the earths surface that it has been exposed at the earths surface for x million years. This just doesnt follow, and ignores erosion.

Also, a fossil rich stratum subjected to weathering will always have fossils weathering out at its surface, despite the fact that the surface is being continually lowered by erosion. This should be easy to understand, I would think.

Duvenoy

All of the fossil finds were at one time buried, and rather quickly after death, or indeed being the cause of death. In the case of younger, human finds, they might well have been buried in a funeral ceremony.

The earth is never static. Wind and water, earthquakes and so forth are responsible for bringing both fossil and ancient bone to the surface. Olvaldi (sp?) Gorge, in Africa, is famous for locating ancient, human remains eroded out on the surface.

doov

Ergaster

They have eroded out. The earth is a dynamic place--the surface always changes. Seas flood continents or lakes fill basins or rivers flow and dump sediments. Sediments turn to rocks. Any dead critters that have managed to get buried turn to fossils. Seas retreat from continents, lakes dry up, rivers divert or disappear, and sediments erode away. If a fossil hunter happens to be at the right place at the right time, they may be lucky enough to spot bones or fossils that are eroding out and exposed, and an excavation will begin. If not, then the exposed fossil keeps on eroding out until it is lost forever.

Professionals know how to tell from the kinds of deposits whether fossils are likely to be present, but they *still* rely on surface scans to see if any are actually there.

In East African hominid fossil sites, it is common for the research teams to return each year after the seasonal rains, to see what has been exposed due to erosion.

Duvenoy

As kids, we used to hunt arrowheads in just this way. We found a lot of them in farmer's fields and even on gravel roads.

doov

MOJO-JOJO

Is it because most politicians are a bunch of old buried fossils that keep re-surfacing?

Kosh

Would you say that your question has been adequately answered, David?

davidH

Yeah it's been sorta answered.

The only problem that I have is that it seems to be the norm to find these fossils on the surface.

You say that these fossils have been buried for ages and just happen to resurface and so are found.

That being the case how deep would the fossil have had to have been buried so as to avoid errosion in the millions of years that it has been lying there?

Because in order for something to fossilise they have to be rapidly buried - otherwise if on the surface they will erode away or be dragged off by predators etc - Chewed to bits.

However during those millions of years there is nothing to stop the fossil resurfacing and eroding away - like someone else mentioned would happen to these fossils if they aren't found in time.

Yet these fossils are now looked for on the surface - they aren't found partially buried - just lying there.

Due to erosion which is why they are looked for in these places (so I am told) they would be long gone during those millions of years.

Question;

How long can a bone last for on the surface before being decomposed or crumbling to nothing?


Yeah, do you guys know any good sites that I can look this up on?

Cause it is really bothering me - there's no logic in just assuming that all these bones now found on the surface were buried and able to fossilise completely - before being brought to the surface by erosion and reburied throughout those millions of years.

Surely there should be nothing left - 3 or more million years is a very very very long time - plenty of time for these things to be no more.

It was just all this that I can't get my mind around.

Yeah but they were originally on the surface - so they would have had to be buried very deep - but erosion would basically cancel out the burying, unless there was a huge event - or bones were dragged down animal dens.

Yeah, but is this the same for all fossils? Usually excavation and digging out is required - but these bits of skull and all are found right on the surface - they are looked for with the eye.

But then is it not just plain bad logic to assume that the fossil was buried so deep that the erosion that took place over the millions of years didn't bring it to the surface until now?

Bearing in mind that places in Africa or where ever are usually dry most of the year and have rains in a few months inbetween.


It's just these things which are hard to ignore.

Camaban

Might like to check here for the answer to at least a couple of those questions

<a href="http://www.howstuffworks.com/question609.htm" target="_blank">http://www.howstuffworks.com/question609.htm</a>

Ergaster

</strong>

Why is this a problem? In the absence of Superman's x-ray vision, it is impossible to know *if* there are any fossils buried in any deposit. Do you propose people just blast at random? The only way to know if fossils exist is to find them on the surface.

</strong>

Who knows? The probablility of erosion depends on a lot of things, but the most important is exposure to weathering factors. Certainly this isn't uniform over the entire earth's surface, and erosional and weathering rates are far from uniform as well. Perhaps you should pick up an introductory geology textbook--most of them discuss this kind of thing in a fair amount of detail.

</strong>

"Rapid" is a relative term. It usually does not mean "instantaneous" or "catastrophic". And (a fact usually not mentioned in creationist sources on fossilization) the vast majority of fossils do, in fact, show ample evidence of post mortem damage and weathering. That is, most bones and shells have been weatherbeaten, broken, trampled, decayed, gnawed by carnivores, scattered--they just eventually got buried before they were *completely* destroyed. The fossils that are in pristine condition are *exceedingly* rare and not indicative of the norm.

</strong>

Yup. Who knows how many great fosils we have *never* found, or never will?

</strong>

Yup; as mentioned, without superpowers, there's no other way of finding them. Although you are mistaken in at least one point: many fossils *are* partially buried or embedded. What often happens is that the paleontologist or fossil-hunter will spot a bit of the fossil exposed on the rock, while the rest of it is still encased in the rock matrix.

</strong>

Probably not very long.

</strong>

You can start here:

<a href="http://www.geocities.com/abeisaw/Taphonomy/TaphonomyLinks.html" target="_blank">http://www.geocities.com/abeisaw/Taphonomy/TaphonomyLinks.html</a>

At least one of the links within that link is by a contributor to this board (not me!).

Here's another:

<a href="http://palaeo.gly.bris.ac.uk/Palaeofiles/Taph/Index.html" target="_blank">http://palaeo.gly.bris.ac.uk/Palaeofiles/Taph/Index.html</a>

</strong>

Well, it's not really an "assumption". Check that intro geology text again. There are rather obvious differences between fossilized and "fresh" bone, and experts generally can tell whether they've got a fossil or simply a piece of a recently dead critter.

</strong>

If you are still assuming that the fossil itself has been lying exposed for "millions of years", I thought we had pretty much disposed of that. Nobody assumes any such thing. Fossils found on the surface have not been there for very long.

It is not "bad logic", it is geological fact. Get thee to that intro geology textbook and look up "rock cycle". And I don't know what you could mean by the phrase "until now". The rock cycle is one of these endless things: fossils did not wait around until paleontologists were invented before they started to erode out of outcrops. I have no doubt at all that T. rex stomped lots of trilobite fossils to powder in his travels.

[ September 16, 2002: Message edited by: Ergaster ]</p>