Why are fossils found in sedimenta rocks but no in igneous or metamorphic rock?

Answer 1

there arnt any rocks in metamorphic because they would be destroyed by whatver made the rock, the igneous rock is made from lava/magma when it hardens so any fossil structure would burn or disintegrate before the rock even solidified, the sedimentary rock is covered by more layers of dust or dirt or rock after the remains (fossil)is there many times the remains dont survive becoming fossils even sedimentary rock because of the pressure or erosion.

Answer 2

It all comes down to how the rock is made. Sedimentaryrocks form as sediments in the oceans and the sea sink down over time to the sea bed forming layers. These sediment can include skeletal remains of animals who died in the body of water, silt and plant remains. Over millions of years more layers are added on top, compressing the layers below. Eventually the whole lot is pressed so hard that it turns into rock. During the laying down of the sediments, dead sea and other creatures can also sink down into the sediments and eventually get embedded in them, so that when the sediments form rock, the remains (by now, usually just bones) are left, so that we can identify them as fossils millions of years later. With movements in the earth's crust, what was once a sea bed millions of years ago could be mountains today, and hence the fossils contained there are accessible. Igneous rocks form in another way. These are rocks that were made from molten lava in volcanoes that oozed out onto the surface and cooled. As no sediment depositing took place, no creatures would be found there and hence no fossils. If the igneous rock did happen to flow over a dead creature and absorb it, the immense heat of the molten rock would destroy any creature and its remains long before it had any chance of becoming embedded in the cooled rock and forming a fossil. Metamorphic rocks were originally sedimentary rocks, and may well have one day contained fossils, but these rocks got buried deeply over millions of years and have been affected by immense heat and pressure as they were compressed by the rocks above and edged themselves nearer the earth's molten magma below. The change they underwent is called metamorphosis (it is the same word that describes the change from caterpillar to butterfly, or tadpole to frog) and therefore any fossils that were originally in these rocks would be destroyed by the heat and pressure as the metamorphic rock formed.

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Fossils ARE found in metamorphic and igneous rocks!

Fossils are the remains of organism that lived on the surface of the Earth. For a fossil to form, parts of the animal need to be incorporated into the rocks forming at the Earth's surface.

These rocks are bay and large sedimentary rocks.

However lavas can and do sometimes engulf living things and fossils can form in lavas, which are of course Igneous rocks. The human fossils found in the Ruin of Pompeii would be one example of this.

Fossils can also be found in Metamorphic rocks. Obviously the metamorphic rock must be made out of fossiliferous sedimentary source rock, but the metamorphic process does not always destroy the fossil content - as proof of this I would cite the "delabole butterfly" a deformed fossil found in a slate.

Answer 3

Igneous rocks are new rocks that are formed from magma, metamorphic rocks are old rocks returning to magma. Sedimentary are the only one in between that exist where living things can die and become fossils.

Answer 4

Metamorphic rock was formed when there was nothing alive to form fossils. Igneous comes form lava which makes it impossible for fossils to be present. Fossils form in sedimentary because of how it is formed. From sediment in which something is deposited and then covered.

Answer 5

Igneous and metamorphic rocks are created by heat from magma. Metamorphic rocks are also created by pressure. The heat and pressure would obliterate and change chemically any fossils previously in these rocks - they would melt and be destroyed.

Answer 6

Igneous rocks are formed from hot and molten rock. Any life trapped in them as they form and solidify will therefore be burned up and destroyed. However, sedimentary processes happen in bodies of wate and therefore there is a chance of bit of dead organisms being incorporated into the sediments and becoming fossilised.

Answer 7

igneous rocks come from lava and organisms wouldn't survive under the intrusive rock i don't know metamorphic

Answer 8

A fossil would be destroyed in a metamorphic or igneous rock. Therefore, it is only seen in sedimentary rocks because that is the only rock which it can survive in.

Answer 9

Organisms can get trapped and fossilized as the layers of the sedimentary rock form.

Answer 10

Igneous rocks form from hot molten rock. Metamorphic rocks form under immense heat and pressure. These conditions will tend to destroy any fossils.