Question

How do index fossils help determine the age of rocks layers?

Answer 1

To date rocks geologists first give a relative age to a layer of rock at one area. At that point they can give similar age to coordinating layers of rock at different areas. Certain fossils, called index fossils, help geologists coordinate rock to layers. Index fossils have an extremely short life expectancy which implies they just can be found in a specific age.

Complete answer:
Record fossils will be fossils of living creatures that lived during just a single brief timeframe. A layer rock with an index fossil in it is close in age to another layer of rock with a similar kind of index fossil in it. Despite the fact that rock layers are of various locales, index fossils demonstrate that the layers are close in age.
To date rock layers, geologists first give a relative age to a layer of rock at one area and afterward give a similar age to coordinate layers at different areas. Certain fossils, called index fossils, help geologists coordinate rock layers. To be valuable as an index fossil, a fossil should be broadly distributed and speak to a kind of life form that existed for a short time span. Index fossils are helpful in light of the fact that they tell the overall periods of the rock layers wherein they happen. Geologists utilize specific kinds of living beings, for example, trilobites, as index fossils.

Note: Index fossils are those fossils which have wide geological dispersion and short life expectancy. so in the event that they are found in a specific age, it implies they have a place in that age and they can't be found in developments more younger than that. for instance if there is an index fossil of Permian age, we can correlate the permian age developments