The Geological Age of the Earth

Abstract

IN delivering the twenty-seventh Robert Boyle lecture last year, Prof. J. Joly returned to his attack on the higher estimates of geological time which have been based on the lead-ratios of uranium-bearing minerals. He favours an estimate of 160 to 240 millions of years for the period that has elapsed since the Archaean, and refers to the lead-ratios of certain thorium minerals and to the sodium method of arriving at the age of the oceans as providing confirmatory evidence. It can, I think, be shown that in both cases the data used are misleading, and that the results from both methods can be readily interpreted to support the very estimates to which Prof. Joly considers they are opposed.