Later, this date was confirmed by two other dating methods (paleomagnetism and fission tracks), and was widely accepted.Then Richard Leakey found a skull (called KNM-ER 1470) the KBS tuff, a skull that looked far too modern to be 3 million years old.You may already know how to date a fossil with a rock.But did you know that we can also date a rock with a fossil?
But sometimes, a scientist finds a couple of rock outcrops that are separated by a wide distance.
As an example of how they are used, radiometric dates from geologically simple, fossiliferous Cretaceous rocks in western North America are compared to the geological time scale.
To get to that point, there is also a historical discussion and description of non-radiometric dating methods.
So Curtis and others redated the KBS tuff using selected pumice and feldspar samples, and obtained an age of 1.82 million years.
This new date agreed with the appearance of the new skull.
We talked about relative dating of rocks and how scientists use stratigraphic succession to compare the ages of different rock layers.