The
epizonal Ag-Pb-Zn vein deposit at San Bartolome is characterised by a base-metal
sulphide assemblage containing the spectacular development of interpenetrating,
bladed networks of pyrrhotite which have been replaced by marcasite and pyrite.
A similar assemblage displaying the same crystal habits and textures are also a
diagnostic feature of the Sn and SnAg deposits ofBolivia. On this
basis, it is reasonable to conclude that both deposits were formed from fluids
of similar nature and origin. Although no economic accumulation of Sn is known
in San Bartolome, further comparison of the geologic setting, age, mineralogy,
fluid inclusion data and magmatic association of this deposit with the Bolivian
systems has highlighted additional similarities consistent with a hypothesis
that more extensive Sn mineralisation might exist in the San Bartolome
area.