Tests by other scientists using paleomagnetism and fission tracks confirmed the lower date.So by 1980 there was a new, remarkably concordant date for the KBS tuff, and this became the one that was widely accepted.Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).
The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age.
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.
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.
Many atrocities were perpetrated on Aboriginal communities because of these evolutionary beliefs.