A textural and chemical analysis of the Hanson Lake ore deposit, Saskatchewan
Abstract
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.