A Lognormal Distribution of Metal Resources

For national or global resource estimation of frequencies of metals,a lognormal distribution has commonly been recommended but not adequately tested.Tests of frequencies of Cu,Zn,Pb,Ag,and Au contents of 1 984 well-explored mineral deposits display a poor fit to the lognormal distribution.When the same metals plus Mo,Co,Nb2O3,and REE2O3 are grouped into 19 geologically defined deposit types,only eight of the 73 tests fail to be fit by lognormal distribution,and most of those failures are in two deposit types suggesting a problem with those types.Estimates of the mean and standard deviation of each of the metals in each of the deposit types are provided for modeling.