Indeed, the "Secret Of The Southwest" was revealed.An Isotope Called Carbon-14 But alas, pattern-matching in order to date when a tree was cut isn't always possible.The technique hinges on carbon-14, a radioactive isotope of the element that, unlike other more stable forms of carbon, decays away at a steady rate.Organisms capture a certain amount of carbon-14 from the atmosphere when they are alive.Dendrochronology and radiocarbon dating have intertwined histories, she explains, with roots firmly planted at the UA.A 1929 edition of National Geographic boasts, "The Secret Of The Southwest Solved By Talkative Tree Rings." The 35-page article, penned in whimsical prose, was written by Andrew Douglass, the UA scientist who invented tree ring science. In addition to his work as an astronomer at the UA's Steward Observatory, Douglass was the first to discover that tree rings record time.The clock was initially calibrated by dating objects of known age such as Egyptian mummies and bread from Pompeii; work that won Willard Libby the 1960 Nobel Prize in Chemistry.But even he “realized that there probably would be variation”, says Christopher Bronk Ramsey, a geochronologist at the University of Oxford, UK, who led the latest work, published today in Science.
She will lead efforts to combine the Lake Suigetsu measurements with marine and cave records to come up with a new standard for carbon dating.Preserved leaves in the cores — “they look fresh as if they’ve fallen very recently”, Bronk Ramsey says — yielded 651 carbon dates that could be compared to the calendar dates of the sediment they were found in.The recalibrated clock won’t force archaeologists to abandon old measurements wholesale, says Bronk Ramsey, but it could help to narrow the window of key events in human history.In 1929, with a beam from Show Low, Arizona, Douglass was able to bridge the gap for the first time ever.Dates were assigned to Southwestern ruins with certainty.If a Bigtooth Maple were cut down on Mount Lemmon in 2016 and it had 400 rings, you would know the tree started growing in 1616. What if it's been used to build a home or a ship or a bonfire?