The Metallogenic Epochs of Tasmania

The study of the metallogenic problem in Tasmania offers most exceptional opportunities for the investigation of the general principles controlling the formation of ore deposits, because there are developed in this State a wonderful variety of deposits concentrated within an unusually small area. It will be seen in the subsequent pages that as a reuult of the research described therein not only has some approach to finality in the solution of the Tasmanian metallogenic problem been attained, but that some new light has been thrown on the mechanism of the derivation of ore-bearing solutions from igneous magmas in general. The method of approach to the problem of metallogenesis, used in this investigation is that of the geologic relationships of the ore deposits - their relation to the geologic structure and history of the region in which they occur. All phases of geologic knowledge are applied to the problem - stratigraphic, tectonic and plutonic geology all being called upen to contribute evidence for the determination of the age and genesis of the ore deposits. The work is accordingly presented in two parts - Part I being the Geologic Background and Part II the Statement of Metallogenesis. The essential geologic facts are given in Part I in order to supply the foundation for the detailed examination of the ore deposits in Part II