Sediments

Originally posted here
EvC Forum: Why Only Creationism So Politicized? This is apparently something from Ken Ham. No reference has been given however.The poster was asked: and wondered why?I believe I've seen Ham speak on TV. I'm pretty sure he's a YEC and that's where the comment is coming from. It is odd he'd suggest there is enough sediment to "account for about 62 million years" if that 10,000 times longer than he think earth has existed. Isn't it?

This is copied from the "wrong" forum to carry on the debate if amsmith986 would like to.A small warning Mr. Smith. If you keep poppling up new topics without answering issues you've already raised you'll be overwhelmed trying to keep up. If you have an number of issues you think are important pick one or two and finish with those first.I'm not trying to constrain you, of course. But you're in a tough position. Unless you are very expert in some area you'll find that almost everything (like this topic) has been brought up and/or answered already. You'll just get deluged with things to answer if you don't pace yourself a lttle.Now then one response to the sediment issue was No response to this issue yet.

And another resonse was (by crashfrog):

There, now we have the sediment issue here where i hope it belongs. Can someone clean up the other topic?Dear Admin:
Is this ok? I'm just trying to both stay on topic elsewhere but at the same time not cut Mr. Smith off before he gets started.

Question: Can someone explain how fossils get trapped in sediment that takes (in some cases) thousands of years to accumulate? What is wrong with testing a hypothesis that only cataclysms (volcanic eruptions, earthquakes, meteor strikes, etc.) produce the conditions necessary for trapping an organism and preserving its structure, before decay or absorption or scavenging of the organism can occur?

Well, the short answer is, "They don't get trapped in sediments that take years to accumulate." Compared to the astronomical number of individual life forms throughout history, fossilization is a pretty rare event.Generally you find fossils in situations where bones aren't likely to be disturbed. For instance, tar pits. But some predators , who tend to drag carcasses back to safe places to eat, tend to dicard bones into piles. Sometimes these garbage piles go undisturbed until they've covered in mud or something.The question isn't "can fossils be created by catastrophic means" because the answer is clearly "yes they can". The question is, "Are catastrophic means sufficient to explain the deep, broad, and generally well-sorted fossil record?" The majority of geologists and paleontologists say the answer is "no."(p.s. I'm no paleontologist so the examples of fossilization I've given shouldn't be taken to be definitive.)

I can try, with one example. Lakes, under some conditions, can have a fairly thick layer of oxygen-free water near the bottom, while supporting plenty of life up near the surface. Microscopic organisms like diatoms and coccolithophores can grow very well up top, with their shells, as well as silt and clay brought into the lake by streams, providing a continuous source of sediment that rains down through the "anoxic" layer. Any larger creature (like an archaeopterex, fish, or insect) that happens to die and sink into this oxygen-free sediment will be largely protected from rotting away - no predators or scavengers can live without oxygen, and the only bacteria that do live there are pretty slow eaters, so to speak. So the animal remains will be buried by sediments, with at least a good shot at traces being preserved. If the sediment in question eventually gets buried enough to become rock, and then gets unburied enough for someone to find it, we have a fossil.There are fossils known from such things as volcanos - Pompeii comes to mind - but many more are known from rocks that show no sign of any violent event while they were forming. A lot of the fossils out here where I live, in fact, are remains of reef-dwellers, that could only have lived in clear, calm, shallow water. And a reef 500 meters thick could have only grown a millimeter or two at a time, as the "foundation" it was on slowly sank relative to the sea it was growing in - otherwise you wouldn't find the fossil sponges and such that lived there rooted in their growth positions.So to answer your question: the field of taphonomy is the study of how fossils form, and it has long since established that processes that aren't cataclysmic are responsible for many (nearly all?) fossils.

Thanks. That explanation does help. Any thoughts on whether or not the Grand Canyon in Arizona was formed by massive (multiple) volcanic explosions, a la Mt. St. Helens?This is a critical question for Creationists, because young earth theories require the layers formed in the Canyon to have been deposited rather quickly. Similarly, it is critical for Evolutionists, because the layers formed in the Canyon (and correlated in other locations around the world) are relied upon to establish an approximate age for the earth of several billion years.

Have a look at http://www.geocities.com/earthhistory/
for an in-depth treatment of the Grand Canyon. In short, though, a wide variety of sediments are cut by the GC, including wind-deposited desert sands, complete with animal tracks. Tough to get in a flood.

Well, I'm no paleontologist either, but I may be able to answer some of your questions.First, there are several types of fossils:1. trace fossils (e.g., tracks, burrows, tunnels, etc. created by an organism);
2. mold fossils - a void in the sediment left following the decomposition of an organism;
4. cast fossils - an impression of the organism when a mold has been filled in;
5. body fossils - a fossil that is represented by its own remains that are either altered (mineralized) or not.The main reason fossils form is because they happen to have been buried relatively quickly after death - I'm speaking mainly of animals. Otherwise, as Crash stated, their remains become scattered. Quick burial can occur as a result of dying and sinking in mud (swamp, for example), drowning during a flashflood and buried in the sediment, falling in tarpits, getting buried during a sandstorm, buried under ash (as you mentioned), etc. The most common fossils you hear about are the ones ones that have been replaced by silica. This allows them to survive much easier than the other ones. Getting silica to replace organisms in a natural setting is no easy task; however, once silica is present, it doesn't have to take millions of years. Just depends on the amount of silica present. I believe the most common types of fossils found are trace fossils, but I am not positive.

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What is wrong with testing a hypothesis that only cataclysms (volcanic eruptions, earthquakes, meteor strikes, etc.) produce the conditions necessary for trapping an organism and preserving its structure, before decay or absorption or scavenging of the organism can occur?

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The problem is that fossils do not form ONLY as a result of cataclysmic/catastrophic events, as I illustrated above. Because cataclysmic events can and do form fossils, a hypothesis that tests ONLY that scenario is sure to produce the desired results.I think you are under the misguided notion that non-Creationist geologists, paleontologists, etc. do not acknowledge cataclysmic events. That is not true. Geologists are deceptively labelled as 'uniformitarians' (or something like that) by Creationists, who seem to acribe a completely different meaning to that word. They suggest we cannot envision cataclysmic/catastrophic events, but that is completely untrue. We can recognize ancient floods, mudflows, avalanches, landslides, and meteor impacts (actually a little harder to find if buried) in the geologic record.We do not believe that everything in the geologic record took millions of years to form. Uniformitarianism has nothing to do with the amount of time it takes for something to form geologically, but rather that what is happening today, has happened in the past. In other words, that the present is the key to the past.This allows a geologist to look at a river and make comparisons. I'm sure you could easily tell us all what a river looks like. If in the mountains, it is very energetic with lots of white water. It tends to have a lot of large rocks and boulders, sand isn't as visible unless you go to a slower portion (where the fish tend to be), the sides can be rather steep and deep, and it doesn't have too many bends.Conversely, a river down in the valley tends to meander, has much more sand and mud/clay particles, and sometimes, a lot less rocks and boulders. The bends will have steep banks on the outside of the bend while it will be muddy and possibly marshy on the inside of the bend. As the river moves back and forth within it's own bed, it produces cross-beds and deposits different sized sediment - visible as layers. If the water level drops, the river slows down, depositing more of the finer particles and possibly allowing the inside bend to dry out more, meaning different vegetation, for example, or oxidation, or soil devlopment. If the water rises, that inner bend area will become completely covered with water, possibly burying the plant material, soils, oxidation, and depositing more mud/sand/cobbles, etc on top of all that. Then of course, you have flood plains, which have their own vegetation and depositional signatures.Okay, you can take all this knowledge and compare your real-world observations to something buried in the geologic record. We see the exact same things, such as the steep sided banks, the meandering cross-bedded river beds, the banks developed on the inside of bends. We can see where rivers broke through their levees, when they flooded, when they ran dry. We can map their courses, even.Now imagine if we can see all that in the rock, what if we look a little further away from the river? We can see where sand dunes developed during the same time, where deltas developed, where alluvial fans formed from material coming off a mountain range (which can at times tell us that uplift must have occurred, otherwise no fans would form). From the fossils, we can tell whether the land was forrested, a desert, a swamp, etc.That is 'uniformitarianism.'[This message has been edited by roxrkool, 05-08-2003](edited to replace "swampy" with "marshy". )[This message has been edited by roxrkool, 05-12-2003]

Excellent answers. I'll visit this site more often when I have more questions.Would a question about geological phenomena (such as material absorption and leaking, or leaching) belong under sediments? Or should it be treated somewhere else?