Twobrothers
Jr. Member
- Jun 7, 2017
- 63
- 53
- Primary Interest:
- Other
Interesting topic for discussion. I am sure there is more to it but this is what I've put together so far. Little bits pieces and clues over the past few months. Heres my summary of understanding and an article and video that help back up it up. Hope this is helpful to someone. Such a dynamic process. Wish I would've known all this right off the bat. I love learning new things! Lot of fun! Very interested to hear other people thoughts, opinions and theories on the matter.
It's a physical, chemical, and biological process all taking place together to transport and re deposit gold.
Physical side:
Gold breaks out of host rock due to physical weathering and due to its physical density travels as low as it can go due to gravity and hydrologic dynamics. Little pieces of gold "seed" stream beds or wherever is the lowest place they can travel. Gold has a physical affinity for itself and little pieces can agglomerate together and fuse.
Chemical side:
Gold starts as a complex with rock. It is dislodged from the rock by physical weathering assisted by chemical means. Sulfide eating bacteria eat away as the sulfur in hydrothermal solutions making Sulfur Dioxide (gas) and dilute solutions of sulfuric acid (liquid). These sulfur solutions eat away at the vein and host rock but cannot compound with the gold. However other solutions with chlorine are released by the dilute sulfuric acid produced and the can compound with gold to form a liquid solution of gold chloride. This is transported down the watershed with precipitation runoff events. Many naturally occurring compounds can reduce gold chloride back to its metallic state.
Biological side:
Gold starts as a complex with rock. Certain chemical constituents of the vein and or host rock material are eaten by bacteria which enable gold to be physically released from its host rock. Chemical decomposition of the host rock also releases chlorine containing solutions which can dissolve gold and form an aqueous solution. Certain bacteria live in/on/around the small pieces that physically weather out (the condensation nuclei) and eat gold chlorides to re deposit metallic gold which helps to form nuggets and grow nuggets creating placer deposits which can have pieces of gold many times larger than naturally occurs in the vein.
http://www.mdpi.com/2075-163X/3/4/367/pdf
https://youtu.be/LQVnKeV5Dz0?t=2m35s
It's a physical, chemical, and biological process all taking place together to transport and re deposit gold.
Physical side:
Gold breaks out of host rock due to physical weathering and due to its physical density travels as low as it can go due to gravity and hydrologic dynamics. Little pieces of gold "seed" stream beds or wherever is the lowest place they can travel. Gold has a physical affinity for itself and little pieces can agglomerate together and fuse.
Chemical side:
Gold starts as a complex with rock. It is dislodged from the rock by physical weathering assisted by chemical means. Sulfide eating bacteria eat away as the sulfur in hydrothermal solutions making Sulfur Dioxide (gas) and dilute solutions of sulfuric acid (liquid). These sulfur solutions eat away at the vein and host rock but cannot compound with the gold. However other solutions with chlorine are released by the dilute sulfuric acid produced and the can compound with gold to form a liquid solution of gold chloride. This is transported down the watershed with precipitation runoff events. Many naturally occurring compounds can reduce gold chloride back to its metallic state.
Biological side:
Gold starts as a complex with rock. Certain chemical constituents of the vein and or host rock material are eaten by bacteria which enable gold to be physically released from its host rock. Chemical decomposition of the host rock also releases chlorine containing solutions which can dissolve gold and form an aqueous solution. Certain bacteria live in/on/around the small pieces that physically weather out (the condensation nuclei) and eat gold chlorides to re deposit metallic gold which helps to form nuggets and grow nuggets creating placer deposits which can have pieces of gold many times larger than naturally occurs in the vein.
http://www.mdpi.com/2075-163X/3/4/367/pdf
https://youtu.be/LQVnKeV5Dz0?t=2m35s
Upvote
0
