STATISTICAL-MODEL FOR DISTRIBUTION OF COPPER, LEAD, AND ZINC IN CANADIAN APPALACHIAN REGION

Sulfides from the Gull Pond cupriferous iron sulfide deposit of Ordovician (?) age, associated with cordierite-anthophyllite and cordierite-andalusite biotite rocks, show only a limited spread in 34S values: +0.2 to +7.6 per mil with a mean of +4.2 1.8 per mil. Although the pyrite-pyrrhotite-chalcopyrite-magnetite ores have undergone recrystallization during Devonian thermal metamorphism, sulfur isotopic compositions, especially for pyrite, are considered to reflect original 34S values. Much of the pyrrhotite and some of the magnetite present in the Gull Pond ores were produced during thermal metamorphism. Original ore mineral assemblages at Gull Pond were likely similar to those in ophiolitic cupriferous iron sulfide deposits (Whalesback, Little Bay, Tilt Cove, etc.) elsewhere in Notre Dame Bay (pyrite magnetite) and much of the sulfur in the Gull Pond deposit, like the others, was derived from Ordovician sea-water sulfate.; It is assumed that random sampling by means of blocks of constant weight yields lognormally distributed copper, lead, and zinc concentration values in the Canadian Appalachian Region. The cumulative frequencies of the highest values belonging to these distributions are determined by approximation from the average grade values and ore tonnages of all types of sulfide deposits in the region. It is demonstrated that the fitted lognormal distributions are not sensitive to rather large changes in the assumed weight of the segment of the earth's crust used for control and in the assumed clarke values. This approach may be useful in estimating subeconomic resources.