Applied Mineral Exploration
Discussion and research relevant to mineral
exploration. Cosmo Howley mine - misidentification of "chert" host rock
An initial microthermometric fluid inclusion study of samples from the Enterprise mine, came to the conclusion that the deposit formed from fluids which lacked and CO2 content. A subsequent decrepitation study showed that over 50% of the samples collected had a prominent low temperature decrepitation peak, indicating that CO2-rich fluids were in fact a major component of the mineralising fluids. Samples from the eastern limb of the fold tended to lack CO2, but samples from the ore bearing sheeted and stockwork vein areas always contained CO2-rich fluid inclusions. The Au mineralisation is closely related to the CO2-rich fluids.
The initial study was compromised by the inability
to
collect an extensive suite of relevant samples and the choice of the
operator
to use transparent quartz, rather than the more common milky quartz. In
this case decrepitation analyses were a much more reliable indicator of
the mineralisation fluids than were the microthermometric data.
