What conditions needed for fossil formation? What are the conditions that favor fossil formation? What fossil is preserved in hot dry conditions? What conditions led to the formation of labor unions? What conditions are best for fossil formation? What was the earth's gas abundance 4 billion years ago? Is fossil fuel rewnable or nonrewnable? What conditions makes fossil formation more likely? What conditions favor the formation of fog by radiation cooling?
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What is the leading theory for a formation of fossil fuels? What is the best type of rock for fossil formation? People also asked. How has Earth changed during your current era? View results. What is true of the most recent ice age? What caused disappearance of land bridges? Match the era on the left with its characteristic on the right? Study Guides. Trending Questions. After a shelled animal dies, the strong water motions cause the hard body parts to be broken and worn. Often the shells end up just as rounded grains of sand or gravel, which no longer look like fossils.
For animals without skeletons, like worms or jellyfish, fossilization is a very rare event. When paleontologists find a well-preserved fossil of a soft-bodied animal, it's an occasion for celebration.
For a soft-bodied animal to be fossilized, its body must be protected from decomposition. The body is usually exposed to air and water with a lot of oxygen, so it decomposes rapidly. The animal is likely to be fossilized only if it is buried soon after it dies or when it is buried alive! Even then, it is likely to decompose, because water that seeps through the sediment around it usually is rich in oxygen.
Sometimes, however, the body is buried rapidly by fine mud. Water seeps through mud much more slowly than through sand, so the body does not decompose as fast. Environments such as rainforests teeming with life and in a hot and moist climate are also poor places for fossils to form as a carcass can decay quickly and not have time to be buried. Similarly a rocky mountaintop is a poor place for fossils to form with no fine sediments being laid down.
A nice floodplain or stagnant lake or a coastal lagoon is great, however — not too much decay and lots of mud or sand swirling around in the water — and deserts too can be good. The organisms themselves will have an effect too, and not just in terms of their anatomy or where they lived.
Those with large populations that ranged far and wide would have many more individuals which could be buried and preserved, but a small group restricted to a small area less so. Similarly, those species that lasted for millions of years stand a better chance of hanging around for us to find compared to those that came and went in the blink of a geological eye. Time can also play a different role in making fossils unavailable.
Earth's geological processes are mostly slow, but the tectonic plates do move over time and will eventually shift to the point that what is currently on the surface will be covered or destroyed. That means the older a fossil is and we are talking about hundreds of millions of years , the more likely it is to have been shunted deep underground or lost forever and thus older fossils tend to be more rare.
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