Scientists analyze these ice cores to determine how the climate has changed over time, as well as to measure concentrations of atmospheric gases.The longest cores have helped to form a record of polar climate stretching hundreds of thousands of years back.
Recent advances in K-Ar geochronology, specifically the Ar dating has been a major factor in this success.
During the latter half of this century anthropological surveys in East Africa have made significant contributions to understanding how the human species has evolved.
In the past two decades, particularly, discoveries of our fossil ancestors have been made in unprecedented numbers and diversity.
Yet even this seminal K-Ar dating study was plagued by the seemingly insurmountable problem of contamination.
The principal materials for dating East Africa hominid sites are volcanic ashes, yet many of these ashes are not deposited as primary air fall (Greek for ash).