(U-Th)/He Information

He dating has been around since the very beginning of radiometric geochronology. It was the first radiometric technique ever used to estimate the actual age of geologic materials, with pioneering scientists like Ernest Rutherford and R.J. Strutt measuring dates based on the accumulation of He in various rocks. It is amazing enough that they were able to measure He production rates and concentrations, let along made reasonable interpretations of the dates. Their measurement apparatus involved boiling large volumes of rocks in acid, and then pushing the He through the glass tubing using gallons of mercury. Below is an example of the experimental apparatus used by R.J. Strutt, and described in:

Strutt, R.J., 1910, Measurements of the Rate at Which Helium is Produced in Thorianite and Pitchblende, with a Minimum Estimate of their Antiquity: Proceedings of the Royal Society of London, Series A, Containing Papers of a Mathematical and Physical Character, Vol. 84, n. 571, pp. 379-388

Fortunately the facilities we use to measure dates and our understanding of their meaning has advanced significantly, as you can see on our Analytical Facilities page.

On the following pages we have a brief overview of the (U-Th)/He technique, as well as a list of resources that lab users may find helpful.