For dating, eggshells are better
But ash is not always current. In Africa, nonetheless — and before the Holocene, through the center East and Asia — ostrich eggshells are common. Some web sites also contain ostrich eggshell ornaments produced by early Homo sapiens.
Elizabeth Niespolo, during the time a graduate student in UC Berkeley’s Department of world and Planetary Science, splitting uranium from thorium in a lab at the Berkeley Geochronology Center. (Picture by Warren Sharp, BGC)
A graduate student in UC Berkeley’s Department of Earth and Planetary Science, conducted a thorough study of ostrich eggshells, including analysis of modern eggshells obtained from an ostrich farm in Solvang, California, and developed a systematic way to avoid the uncertainties of earlier analyses over the last four years, Sharp and Niespolo, at the time. Continue reading “Ages are mounted on some archeological sites older than 50,000 years through argon-argon ( 40 Ar/ 39 Ar) dating of volcanic ash.”