Why are fossils found in sedimentary rocks only?

Answer 1

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They actually can be in other rocks, but not in their original form. Being an igneous rock means they passed through a volcano or divergent boundary. Being metamorphic means that heat or pressure overtime changed the state of the rock. Sedimentary just means they haven't been changed by nature YET.

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thnx ....this was exactly what i was looking for!!! :D

Answer 2

Fossils are preserved by deposition of layers of material which under the right geologic conditions either mineralizes the organic object or preserves the original shape. This can be done by sediments deposited by water, wind, or chemically in mineral springs. Additionally, fossils can be preserved in conditions where volcanic ash is deposited around the object and preserves the shape or mineralizes fine structural details. It could also be argued that mastodon remains found frozen in permafrost are another type of "fossil" which does not involve rock or mineralization. So I would say that fossils are defined more by their preservation than by a specific type of rock.

Answer 3

fossils are preserved in their native form in sedimentary rocks only, where the layers of overlaid sediments prevent these.

In other forms of rocks, which undergo lots of changes (metamorphic) or those formed by volcanoic eruptions(igneous), due to high temperature and pressure fossils are burned and lost....(mind you had it been possible that these were preserved in igneous, we could have more diverse and rich fossils today obtained from igneous than any other rocks) Rarely a fossil may appear in metamorphic or igneous rock.

Answer 4

because fossils form by sediments filling in a void where an organic object used to be, kind of like a 'foot print' you cant make a 'footprint' in igneous rocks