why aren't fossils found in igneous or metamorphic rocks?

Question

please help, science Homework!

Answer 1

Igneous rocks are basically cooled magma from the earths core. The heat and temperature experienced in the mantle is so extreme that nothing can biological can survive. However nasty is correct when is speaks about Pompii a clever cloggs point you may wish to raise with your teacher.

Metamorphic rocks are rocks which have been formed and either subject to very high tempertures and/or pressures which alter the crystalline structure of the rock fabric. Slate is a metamorphic rock and can on occasion hold some fossil remains. The reason for this is the deformation of the original rock (Claystone) hasnt destoyed the fossil due to favourable conditions.

Answer 2

Fossils can be found in igneous and metamorphic rock it is just very uncommon. For example, if the lava covered a dead animal it could fossilise and some fossils could survive the process f metamorphism.

However the example of Pompeii is not really fossils - these are casts not fossilised remains of humans.

Sedimentary rock is most common to find fossils in because of ow it is formed. Layers of sediment building up can get dead animals trapped between the layers. When the fleshy parts decompose the minerals in the bone can be replaced by rock minerals to form a fossil (there are other methods of fossil forming).

If the sedimentary rock goes through metamorphism, the resulting metamorphic rock would probably contain little evidence of the fossil due to intense heat of pressure changing the make up of the rock.

edit:
"Igneous rock was Metamorphic rock at one time, but has now changed to a different rock altogether, such as a quartz, or a diamond. So again, the changes it went through destroyed any fossilized tissue."

Metamorphic rock was once igneous or sedimentary (although sometimes metamorphic) and goes through metamorphism. Quartz is a mineral not a rock.

Answer 3

Igneous And Metamorphic Rocks

Answer 4

In the best of circumstances, it is much more likely that plant or animal remains will be destroyed by natural forces that preserved. Igneous rocks are formed from magma, which would melt the fossils out of existence. Metamorphic rocks also get heated. Marble gets formed from heating limestone, for example. This will nearly always destroy any fossil form. In some cases, fossils may remain in the zone between limestone which was not altered, because it was not heated enough and marble which was formed by heating of another region of that same limestone. As the transition zone is usually quite limited in volume, the fossils to be found are also quite limited.

Answer 5

Okay. I might be wrong, but here goes:

Metamorphic rock is a changing rock. The changes it goes through destroy fossilized tissue.

Igneous rock was Metamorphic rock at one time, but has now changed to a different rock altogether, such as a quartz, or a diamond. So again, the changes it went through destroyed any fossilized tissue.

But you should do your own homework.

Answer 6

I am going to give a different answer, fossils can be found in ignous and metamorphic rocks. One example are the casts of human remains found in the ruins of Pompii which was covered by a pyroclastic flow. I have seen fossiliferous marbles that also exhibit some degree of metamorphism in Geology lab.

Answer 7

Igneous rocks form from molten lava. If anything lived in there, it was incinerated. Metamorphic rocks form also from high heat and pressure. But keep an open mind. Are you sure that there are absolutely NO fossils in metamorphic rocks?