Absolute dating relative
By matching partial sequences, the truly oldest layers with fossils can be worked out.
By correlating fossils from various parts of the world, scientists are able to give relative ages to particular strata. Relative dating tells scientists if a rock layer is "older" or "younger" than another.
By using this information from rock formations in various parts of the world and correlating the studies, scientists have been able to establish the geologic time scale.INTRODUCTION Scientists have good evidence that the earth is very old, approximately four and one-half billion years old.Scientific measurements such as radiometric dating use the natural radioactivity of certain elements found in rocks to help determine their age.Locally, physical characteristics of rocks can be compared and correlated.On a larger scale, even between continents, fossil evidence can help in correlating rock layers.
The study of fossils and the exploration of what they tell scientists about past climates and environments on Earth can be an interesting study for students of all ages.