Diamonds vs Albany graphite, verrrrrry distant cousinsThanks for the link to the interview with ZEN an GIN, was a good read.
I just wanted to explore the comment made by Aubrey Eveleigh so that people dont come away with the impression that Albany graphite formed in the mantle like diamonds do.
"... but for the most part it’s a breccia pipe. So think of it like a kimberlite pipe where you find diamonds. They come from the upper mantle. It’s much like that."
When taken in conjunction with the additional comment (next paragraph), its clear to me that Aubrey is referring to the mantle source for both Albany carbon and mantle diamonds, and NOT the actual mechanism of mineral formation:
"We’ve been referring to it as hydrothermal. That’s volcanic in origin, derived from the upper mantle of the earth, whereas flake or amorphous is sedimentary in origin. It’s derived from organic material. It’s a totally different style, formed differently, a totally different geological deposit."
Stick2 note on Diamonds: Diamonds are formed in the upper mantle in a very restricted environment of chemical composition, pressure, and temperature, and then transported to the surface or crust by magmatic processes, and may be deposited in alkalic breccia pipes/dikes such as kimberlites, lamprophyres etc. The diamonds will be present in the kimberlite pipe as either a component of mantle xenoliths such as lherzolite or harzburgite or eclogite fragments, or as xenocrysts inside the breccia matrix which were disaggregated from their xenoliths at a late stage.
Stick 2 note on Mantle Graphite: mantle graphite can be formed and transported in much the same way as diamonds, but with different pressure/temperature/chemical constraints i.e. outside of the diamond stability field. Possibly to be discovered by some disappointed geologist looking for diamonds.
Stick2 note on Albany Graphite: described by ZEN as hydrothermal Graphite from a mantle carbon source (as opposed to a sedimentary carbon). As shown in the information video by ZEN on youtube, a deep seated. mantle-derived magmatic body outgasses/dewaters during its evolution, fluids and gases (and maybe magma) are transported upward, and breccia pipes can be formed when these fluids/gases interact with other rocks on their way up. Very large and dynamic breccia systems can form during this type of process. When the chemical/pressure/temperature conditions are right, lots of stuff can precipitate out of the fluid and be deposited as solid (thermodynamics, aqueous geochemistry, and possibly some forms of witchcraft may be involved). In the case of Albany, there seems to be quite a bit of graphite which might be described as hydrothermally precipitated graphite from a mantle source. The purity capability at Albany is related to this type of formation: as Aubrey stated, it is NOT some dirty old organic sediment that got cooked up with all of its impurities; it is graphite that precipitated directly out of solution. Lovely. I have high hopes for this deposit!