How many grains are needed for a provenance study?

Detrital provenance studies using single-grain geochronology are very labor-intensive. This paper presents a method for calculating k, the smallest number of grains in a sample that must be dated to achieve a required level of statistical adequacy. For example, if it is desired that no fraction of the population comprising more than 0.05 of the total is missed at the 95% confidence level, at least 117 grains should be dated. The paper also provides recommendations about cases where fewer than the optimal number of grains have been dated.