Origin of the Zinc Ore Deposits

The vexed question of the origin of the unique ore deposits has often been discussed, and a full treatment of the matter will not be attempted here. The paper by Ries and Bowen (223) contains an excellent summary of the several hypotheses that have been proposed, and this may well be repeated with some comments. Among these hypotheses those outlined below are outstanding.

Igneous-injection hypothesis

This hypothesis was first offered by Rogers (31) in 1836 and was suggested by Spencer in the Franklin Furnace folio in 1908 as the best of several alternatives. It was rejected by Ries and Bowen in 1922 on the ground that it does not account for the admixture of grains of Franklin limestone with the ore minerals. Nevertheless it was advocated by Spurr and Lewis (234) in 1925, the ores being regarded by them as igneous vein dikes of sulphide magma that lost their sulfur by a later distillation at a temperature above that of fusion. How the required oxygen was supplied is not revealed. To the present author it seems that the strongest evidence against this hypothesis lies in the mineral and chemical character of the ores.


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