Interesting Article on How Gold Reaches the Surface

[DizzyDigger]

Saw this article on a site I visit, and though Y'all might find it interesting....

Thermodynamic model identifies how gold reaches Earth's surface

A research team including a University of Michigan scientist has discovered a new gold-sulfur complex that helps researchers understand how gold deposits are formed.

phys.org

 

[Chilli]

Saw this article on a site I visit, and though Y'all might find it interesting....

Thermodynamic model identifies how gold reaches Earth's surface

A research team including a University of Michigan scientist has discovered a new gold-sulfur complex that helps researchers understand how gold deposits are formed.

phys.org

Great, thanks. I always find this type of thing interesting.
Thanks for posting it. 👍

 

[Assembler]

Saw this article on a site I visit, and though Y'all might find it interesting....

Thermodynamic model identifies how gold reaches Earth's surface

A research team including a University of Michigan scientist has discovered a new gold-sulfur complex that helps researchers understand how gold deposits are formed.

phys.org

662 degrees Fahrenheit and 8702.26 PSI appears to be the sweet spot for the tri-sulfur AU / gold compound.

 

[Assembler]

662 degrees Fahrenheit and 8702.26 PSI appears to be the sweet spot for the tri-sulfur AU / gold compound.

It gets a little more interesting when you think about it. For example:

Au in aqueous S-bearing fluids established using less direct methods, highlight an important role of the tri-sulfur ion in gold mobilization and concentration in hydrothermal-magmatic deposits associated with subduction zones.

Both 'gold mobilization and concentration' goes very well (they like each other) with deposits associated with subduction zones.

 

[Assembler]

"Devolatilization of subduction zones" that causes "Hydrous melting" could be the likely chain / pathway for gold and sulfur to make a strong chemical bond creating a "gold-sulfur" bond (Au-S) where the sulfur atoms adsorb onto the gold surface, often forming various structures depending on the coverage level. Something to look for.

 

[Assembler]

If the mantle convection heat zone (1832 degrees F. to 2552 degrees F.) quickly passes / moves into a lower temperature zone by an event. This is within the melting point of gold at 1948 degrees F. , this can quickly cause a strong reaction with different forms of sulfur that is very common in rocks. Some thing to look for and think about.

Sulfur's melt point is 235 degrees F. and the "Gas point" of pure sulfur is 832.3 degrees F.
So the 'sweet spot' of 662 degrees and a lot of pressure is close to the "Gas point" of sulfur.

 

[Assembler]

To help with looking at the diagram of the above article the topic of Ligand availability comes to mind:
Ligands are ions or neutral molecules that bond to a central metal atom or ion. They act as Lewis bases, donating electron pairs, while the central atom acts as a Lewis acid, accepting electron pairs.

Examples of ligands include: water (H2O), ammonia (NH3), chloride ion (Cl-), hydroxide ion (OH-), carbon monoxide (CO), cyanide ion (CN-), oxalate ion (C2O4^2-), and ethylenediamine (en).

An example of a model of gold rich rock formation is attached.

 

[Assembler]

The following will show a relationship of structure and stability factors to look for:


In alkaline solutions, the Au2(HS)2S2- complex is predominant, while in neutral pH regions, the Au(HS)2- complex is present.

A "chelate" is a specific type of "complex" where a central metal ion is bound to a ligand (molecule) through multiple attachment points, creating a ring-like structure, while a "complex" is a broader term referring to any compound where a central metal ion is surrounded by one or more ligands, regardless of the number of attachment points; essentially, all chelates are complexes, but not all complexes are chelates.

Ligand attachment:

A chelate forms when a ligand (chelating agent) binds to a metal ion through multiple donor atoms, creating a cyclic structure, whereas a complex can form with a ligand attaching at only one point.

Stability:

Chelate complexes are generally more stable than simple complexes due to the "chelate effect" where multiple bonds between the ligand and metal ion enhance the stability.

May sound like a lot of talk about something hard to look for yet it is chemistry playing a lead role in how the minerals will move or transfer to the surface of the earth is the point being made here.

 

[Assembler]

The theory may go back to around 1997:

ARTICLEMarch 4, 1997

Synthesis and Characterization of Sulfur-Ylide Complexes of Gold(I). Observance of Intermolecular Gold(I)−Gold(I) Interactions in Solution

https://pubs.acs.org/doi/10.1021/om960748j

 

[Assembler]

Anyone have some example pictures to show this effect of sulfur compounds / complex's ?