Applied Mineral Exploration
Discussion and research relevant to mineral
exploration. Gold-quartz deposits do NOT form from CO2-only
fluids:
Heterogeneous fluid inclusion trapping is everywhere
By: Kingsley Burlinson December 2017
In 1997 Schmidt Mumm et. al. asserted that gold might be
transported in and deposited from pure CO2
(non-aqueous) fluids. Despite gold being only a trace component of
the mineral deposit, which was a quartz vein, there was no attempt
to explain the essential transport and deposition of quartz. The
problem was a failure to understand the immiscibility of CO2-water
fluids and failure to understand the resulting fluid inclusion
assemblages. This series of discussions explains in detail the
characteristics of CO2-water fluids, the way they unmix
into a binary fluid mixture and how fluid inclusions form within
these fluids. With this proper understanding of the CO2-water
system it is clear that water is the dominant constituent and both
the quartz and gold are transported in the aqueous fluid while the
unmixed CO2 fluid plays little or no part in the
mineralising event.
An example of fluid cooling across the immiscibility solvus showing why such heterogeneous fluids are misidentified and how they form CO2-only inclusions from aqueous parent fluids. K. Burlinson, April 2018.
A complete overview of the heterogeneous CO2-water system.
An explanation of the presence of CO2 fluid inclusions in heterogeneous dominantly aqueous fluid systems. The gold and silica are not transported in the CO2 fluid because it is a minor component of the dominantly aqueous, heterogeneous fluid system. By: K. Burlinson, December 2017
Research by Liu et.al. shows a negative correlation between gold solubility and CO2 content in fluids. This confirms other discussions below which point out that mis-interpretation of heterogeneous fluids is the real explanation of anhydrous CO2 fluid inclusions found in some gold deposits. By: K. Burlinson, November 2016
Boiling epithermal fluid systems and immiscible CO2 - aqueous fluid systems are both heterogeneous fluids, but they are very different and must be interpreted differently. By: Kingsley Burlinson, November 2014
Inclusion morphology can indicate that gas filled inclusions must have formed as bubbles within a liquid rather than being trapped from a purely gas host phase fluid. By: Kingsley Burlinson, June 2014
A discussion disputing published work which wrongly claims to prove that gold is transported in pure CO2 fluids. By: Kingsley Burlinson, September 2013
A discussion disputing the transport of gold in pure CO2 fluids. By: Kingsley Burlinson, September 2011