RADIOCARBON DATING OF THE HISTORIC DERBY BOAB TREE FROM DERBY, KIMBERLEY, AUSTRALIA

The paper presents the AMS (accelerator mass spectrometry) radiocarbon dating investigation of the historic Derby Boab Tree from Derby, Kimberley, Australia. This well-known boab (Adansonia gregorii) is frequently considered a prison tree, where Aboriginal prisoners were temporarily incarcerated in its cavity. According to recent research, the Derby Boab Tree was not used as a prison tree. The boab has a closed ring-shaped structure, with 3 perfectly fused stems enclosing a false cavity. A number of six punctiform wood samples, of the size of a grain of sand, were collected from the cavity door wall. The radiocarbon date of the oldest dated punctiform sample was 1285 ± 21 BP, a value which corresponds to a calibrated age of 1185 ± 20 calendar years. This result indicates that the age of the Derby Boab Tree is 1250 ± 50 years. This is the first accurate dating result of a boab and demonstrates that the species is a millennial angiosperm.