Application isotopes carbon dating
‘Dating is absolutely crucial, it underpins everything,’ says Michael Walker.
Based at the University of Wales Trinity St David, he has devoted his career to studying the Quaternary period – the last 2.6 million years and the so-called ‘age of humans’.
well, us.‘The great breakthrough in Quaternary archaeology was radiocarbon dating,’ Walker says.
Developed by Willard Libby in the 1940s – and winning him the Nobel prize in chemistry in 1960 – the basic principle of radiocarbon dating is simple: living things exchange carbon with their environment until they die.
It’s possible to measure the ratios of uranium-238/uranium-234 and thorium-230/uranium-238, the latter of which depends on the former.
To get a clearer picture, scientists are exploiting diverse physical phenomena, from uranium’s radioactivity to life’s preference for l-amino acids.The first excavations in the 1950s and 1960s revealed a hub of ancient human activity, spanning thousands of years’ worth of artefacts.Unfortunately much of it originates from outside radiocarbon dating’s timescale. was almost non-existent,’ says Geoff Duller, a geochronologist from the University of Aberystwyth in Wales.‘We’re kind of at the mercy of geochemistry.’Pike’s team used this method to give a minimum date to red hand stencils found in a cave in northern Spain called El Castillo, which contains the oldest known cave art in the world. This is long after humans were supposed to become anatomically modern, adding to the evidence suggesting that early anatomically modern humans didn’t necessarily act modern. Anatomically modern humans arrived in northern Spain around 42,000 to 43,000 years ago, and Neanderthals died out between 39,000 and 41,000 years ago.But because the stencil date is a minimum age, there’s a chance the Neanderthals could have been the artists.