So there is that wide spread layer of Volcanic ash, known as the Laacher Sea Tephra which is widely used as a dating marker but how old is it, itself?//<![CDATA[ aax_getad_mpb({ "slot_uuid":"f485bc30-20f5-4c34-b261-5f2d6f6142cb" }); //]]>

All with 95% confidence interval:

K-Ar dating gives: 12,900 +/- 560 years before present

A carbon date of the last tree ring of an ash burried tree gives: 12,985 +/- 75 years before present

Counting individual annual sediment layers in a lake finds 12,880 +/- 120 years before present

A so called multi proxy trick combining all kind of techniques gives: 12,859 +/- 116 years

The only common time frame of all these is 12,910 to 12,975 years but the average value is 12.906 years. How would you calculate a statistically acceptable 95% confidence interval?

Thanks

**Physics Forums - The Fusion of Science and Community**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Dating a volcano

**Physics Forums - The Fusion of Science and Community**