Argon dating technique verified

Jeff Poling

Scientists announced this week that a chemical dating technique worked with incredible accuracy when testing sediment of known age.

Scientists from the University of California, Berkeley, published in the journal Science that they used specimens from the Vesuvius explosion that buried the Roman city of Pompeii to test the widely used radioactive-argon dating method. The testing placed the eruption of Vesuvius at 1,925 years ago. Historians place the eruption around 79 A.D., or 1,918 years ago. The margin of error was plus or minus 5 per cent. The researchers feel that they can get the error down to 1 per cent or less.

Radioactive-argon dating is a popular method used for dating ancient sediments. For centuries, the age of layers of sediment were based on geologists' understanding of how long such formations took to form, their relative position to other layers of sediment, and the fossils contained within. Radioactive-argon dating is now used to give sediment layers an absolute date, based on the radioactive properties of argon. This dating technique works only with sediments containing volcanic material, such as ash, in the layer, or with actual lava flows. Layers with no volcanic material are dated using the older methods of relative dating, although now they are dated relative to the absolute dates given by radioactive dating methods.