The gossan of a lead deposit in limestone : Yukon territory

• Main Author: MacDonald, Ralph Crawford
• Format: Thesis
• Language: English
• Published: University of British Columbia 1947
• Subjects: Lead ores > Dawson mining district; Y.T; Blanchard; Yukon; Dawson
• Online Access: http://hdl.handle.net/2429/41737

The interpretation of leached outcrops as guides to the specific minerals from which they were formed has been developed to a rather high degree by earlier workers, among whom Boswell and Blanchard deserve particular mention. In the present work, a gossan that led to the discovery of a lead deposit is described. Since many hand specimens of the limonite from this gossan lack the characteristic boxwork structures described by the authors above, microscopic investigations of thin and polished sections were carried out. However, the gossan is classified into six types mainly on the basis of its physical properties. At least three of these are correlated with types described by Boswell and Blanchard, one of pyrite derivation and the others from galena. The relative solubility of different limonite types in dilute HC1 was not found to be of as much value as some writers have indicated. The mineral deposits to which the limonite pointed the way have not been sufficiently exposed to allow detailed study, but the presence of tremolite and phlogopite in an area of disseminated mineralization indicates that this portion at least may be of contact metamorphic origin. Science, Faculty of Earth, Ocean and Atmospheric Sciences, Department of Graduate