Relative dating diagram
Now, when we use fossils to date rocks, we have to be careful. Remember that some species of animals and plants lived for a very long time, while others existed only for a short period of time.We don't want to use fossils belonging to species that lived for too long; these fossils would show up in more than one rock layer. We have a good sense of the order in which things happened to us (when we were children, students, adults), that is, a relative sequence of events.We can also handle parallel relative sequences (e.g.But there will always be some external events to provide anchors to the relative chronology (where we were when Kennedy was assassinated, or on 11 September 2001, for example).Archaeology also depends on both relative and absolute dating.Free 5-day trial You may already know how to date a fossil with a rock.
You should already understand that the lower rock strata are generally older than the strata found higher up in the rock.
They follow an ordered progression that is very clear and predictable.
Therefore, we can use the succession of fossil assemblages to establish the relative ages of rocks.
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