Age dating methods
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From the mapped field relationships, it is a simple matter to work out a geological cross-section and the relative timing of the geologic events.
His geological cross-section may look something like Figure 2.
A hundred years ago, our ideas about the ages of rocks and the age of the Earth were vague. Judging from the amount of rocks there are, plus the imperceptible rates of the processes forming them—erosion, burial, fossilization, uplift—the geologic record must represent untold millions of years of time.
It is that insight, first expressed in 1785, that made James Hutton the father of geology.
Along the way, we'll learn how stratigraphic succession and radioactive decay contribute to the work of paleontologists.
Consider the following scenario: Paul the Paleontologist is a very famous scientist who has studied dinosaur bones all over the world.
Volcanic rocks – such as tuff and basalt – can be used in dating because they are formed at a particular moment in time, during an eruption.
It is clear that the sedimentary rock was deposited and folded before the dyke was squeezed into place.
By looking at other outcrops in the area, our geologist is able to draw a geological map which records how the rocks are related to each other in the field.
But really, how do scientists figure out how old their dinosaur bones are?
And, what about other findings like fossil fish, plants and insects?