Using deductive reasoning, tell a story in chronological order. There are a few techniques used to help us relatively date rock strata. In the image below, you will see the tracks of a bird, barefoot woman, a business man, a motorcycle, and a really small clown car. There are two main methods determining a fossils age, relative dating and absolute dating.Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages.Using index fossils helps scientists determine the relative age of rock strata.
This makes it ideal for dating much older rocks and fossils.They can show how some species lived and what specie replaced them.They also demonstrate that some species haven't changes all that much.Typically commonly occurring fossils that had a widespread geographic distribution such as brachiopods, trilobites, and ammonites work best as index fossils.If the fossil you are trying to date occurs alongside one of these index fossils, then the fossil you are dating must fall into the age range of the index fossil. In a hypothetical example, a rock formation contains fossils of a type of brachiopod known to occur between 410 and 420 million years.