# Epithermal or Mesothermal?



## rookieminer (Jan 31, 2012)

I'm always looking to learn anything I can about ores and the different types. 
Can anyone tell me how to tell the difference between these two types of deposits?
From what I understand the Mesothermal type deposit is more likely to carry values at a greater depth, and the Epithermal type deposit doesn't hold values very deep.

Thanks in advance for any help.

rookieminer


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## ayeyou (Jan 31, 2012)

You are correct regarding the depth of the two types of deposits . Mesothermal deposits tend to be of a more concentrated vein structure and can go to great vertical depths whereas epithermal deposits tend to produce much larger deposits tonnage wise and are shallower in orientation than mesothermals.Here is a link that explains the different types of deposits.

http://www.almadenminerals.com/geoskool/vein-systems.html#mesothermal


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## Dr. Poe (Feb 1, 2012)

rookieminer said:


> I'm always looking to learn anything I can about ores and the different types.
> Can anyone tell me how to tell the difference between these two types of deposits?
> From what I understand the Mesothermal type deposit is more likely to carry values at a greater depth, and the Epithermal type deposit doesn't hold values very deep.
> 
> ...


Epithermal means "surface hot" and mesothermal means "raised hot". The mesothermal is usually super heated solutions of water, silica acids and dissolved minerals. As silica acids are surfacing and combining with cooler fluids and surroundings, it precipitates into quartz. Quartz, when under pressure, emits a low voltage that precipitates easily reduced metals like gold.
When digging, mining an epithermal deposit, the surrounding rock formations are usually permeated with associated minerals and gold. As you go deeper the hotter deposits are found and the gold bearing lode narrows to cracks filled with quartz and the easiest of metals to reduce. Often the gold precipitates as a telluride, selenide or sulfide in both of these types of "Hot Springs". Regards, Dr. Poe 8)


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