DEVELOPING ESR DATING FOR MARSUPIAL TEETH: RECOGNIZING MULTIPLE SEDIMENTATION EVENTS IN THE LAKE EYRE BASIN, AUSTRALIA
Electron spin resonance (ESR) dating uses radiation-sensitive signals in tooth enamel. It can date tooth enamel from approximately 10 ka to 5 Ma in age, depending on the sedimentary and internal dose rates. U concentrations in the dentine fall into four distinct groups, with minimum values near 7 ppm and maximum values, 124 ppm. U concentrations in the enamel also show significant variation. The ages for the teeth grouped into four distinct groups with respective calculated ages of 80-100±5 ka, 400-500±20-30 ka, 1.1±0.1 Ma, and 2.7±0.2 Ma assuming linear U uptake. These data suggest that a substantial proportion of the teeth in the Katipiri actually have been derived from older units. While it impossible to know the precise age of the reworked teeth without detailed sedimentological of these units or ESR isochron analyses of the teeth, their presence indicates that erosion and redeposition was extremely active during Katipiri times, in late Oxygen Isotope Stage 5.