Radiocarbon Dating of Biogenetic Opal

Science  07 Apr 1967:
Vol. 156, Issue 3771, pp. 66-67
DOI: 10.1126/science.156.3771.66


Approximately 75 grams of biogenetic opal were isolated from 45 kilograms of soil by employing gross particle-size and sink-float specific gravity fractionation procedures. After pretreatment of the sample to remove extraneous organic and inorganic carbon contaminants, the carbon occluded within opal phytoliths was dated at 13,300 ± 450 years before the present. Therefore, biogenetic opal is stable for relatively long periods.