Arthur Holmes. Portrait of Arthur Holmes (1890- 1965), English geologist. After taking up a scholarship to study geology and physics at Imperial College in London, he became interested in determining the age of the Earth. The new technique of radioactive decay dating allowed him to find the absolute age of fossils, and correlate this data with their known relative dates. This work also made him a firm supporter of the new continental drift theory, and he found that the heat produced by radioactive decay in the Earth could drive plate movements. As well as this, he wrote Principles of Geology, one of the most successful textbooks ever written.