A scientist of dedication and foresight, Arthur Darnley devoted most of his career to the development of techniques to minimise the subjectivity of geological observations.
Born on February 28, 1930 in West Hartlepool Co. Durham, and schooled at Worksop College in Nottinghamshire, at 18 Darnley entered the RAF as a National Serviceman. After training as an instrument technician he was posted to Germany; there during the Berlin Airlift the urgent responsibility of keeping overworked cargo planes safely in the air was surely a strongly formative experience.
From National Service he moved (1952) to a Natural Science course at Cambridge, specialisation in geology partly preparing him for his two-year spell as Mine Geologist on the Copper Belt of Northern Rhodesia.
There, inter alia, he was able to show that the standard exploration technique of the time gave results that varied with seasonal changes in the water table. He returned to Cambridge in 1954 with material for a PhD project; working more on the chemistry of the host rocks than on the ores themselves, he was able to dispute forcibly the then received opinion on Copper Belt genesis. In 1957 he moved to the Atomic Energy division of the Geological Survey, with responsibility for uranium-thorium-lead age determinations. The analytical setup provided he found less than satisfactory, and as a diversion he became the prime creator of a portable radioisotope X-ray fluorescence analyser for rapid in situ analysis of fine-grained ores.
In 1966 Darnley moved to broader pastures with the Geological Survey of Canada in Ottawa. Here, at a time of unparalleled expansion, he was able to develop airborne gamma ray spectrometry as a tool for mapping the surface distribution over wide areas. The GSC then had funding adequate to buy its own aircraft and consequently for a time became the international leader in airborne geophysics. The wider value of the technique was demonstrated when it proved to be the only system capable of locating the radioactive debris from the crashed (1978) Cosmos 954 in Northern Canada- much to the chagrin of the Americans. Thanks to the endorsement of the IAEA, Darnley had the great satisfaction of seeing the method and related procedures adopted and used in many countries. From his detailed study of uranium and work with IAEA committees he became a firm and articulate proponent of nuclear fission as a valid power source.
In later years his was a more administrative role. He served for 15 years as Director of the GSC's Resource Geophysics and Geochemistry division; on the world scene as chairman of the Global Geochemical Baselines project under the aegis of the IUGS, he played a pivotal role in establishing standardised data necessary to detect geochemical effects of climate change and other human influence on the planet.
Arthur Darnley died on 5 September 2006. He had proved a firm and upright friend for many, a good companion with his quietly quizzical outlook on life. Throughout his distinguished but often onerous career he was sustained by a warm and happy home life, with wife Joan (née Allen) who married him in 1954, and children Robert, Elizabeth Ann, and Ian. Seven grandchildren also survive him. Outwith the family circle he found recreation in the air. Having held a pilot's licence since his Africa days, he greatly enjoyed piloting his own light aircraft and, as he put it, "looking down on the earth from above"
Graham Chinner