A textural and chemical analysis of the Hanson Lake ore deposit, Saskatchewan
Kennedy, David Scott
The Hanson Lake ore body was a small (156,000 tons), massive lens with sharp ore-wall rock contacts and a homogeneous mineralogy. The major sulfide minerals were sphalerite and galena. Textures of the sulfide and gangue minerals indicate that the ore body had undergone deformation and recrystallization. Composition and gross features of the alteration envelope suggest that the deformation and recrystallization are a result of regional metamorphism and metasomatism during the Kenoran orogeny. The relative age of the ore body in relation to metamorphism indicates the ore was deposited penecontemporaneously with the host, volcanic, rocks. The lack of a suitable magmatic source precludes a hydrothermal origin,and shearing within the ore precludes a metasomatic origin for the ore. However, Pb-Pb age of galena in the ore body is not consistent with the author's proposed volcanogenic origin for the ore. The Hanson Lake and Flin Flon group of ore bodies differ in many respects, although they are similar, structurally, within metamorphosed volcanic rocks. The Hanson Lake deposit, with its lack of an extensive alteration zone and its distinctive mineralogy, occurs in older rocks than those of the Flin Flon deposits. The basic differences suggest that the Hanson Lake deposit should not be correlated regionally with the Flin Flon group of deposits, and may account for the lack of good correlation between Co:Ni. ratios of pyrrhotite in the Hanson Lake deposit and in 'economic' deposits of the Flin Flon group.