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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.

• Explaining the formation of CO₂-only fluid inclusions
  

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.

•  Gold deposition from heterogeneous aqueous, CO₂-rich fluids: resolving the enigmatic and misleading hypothesis of deposition from CO₂ only fluids.

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

• Thermodynamic studies confirm that gold is NOT transported in anhydrous CO₂ fluids.

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

•   Contrasting types of heterogeneous fluids. Boiling versus gas-rich aqueous immiscibility systems.

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

•  Spherical or well rounded gas-filled fluid inclusions prove that heterogeneous trapping occurred from a dominantly liquid phase fluid.

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

•  Gas dominated inclusion assemblages may be trapped from aqueous dominant heterogeneous fluids by disproportional trapping

A discussion disputing published work which wrongly claims to prove that gold is transported in pure CO₂ fluids.                 By: Kingsley Burlinson, September 2013

•  Fluid inclusions in quartz cannot prove that non-aqueous fluids CO₂ formed the ore

A discussion disputing the transport of gold in pure CO₂ fluids.              By:  Kingsley Burlinson,   September 2011