Good question. I have the impression they come from high-grade metamorphism of carbon-bearing materials (like limestone and other carbonates) that makes the carbon evolve into carbon dioxide in solution, which precipitates from hydrothermal waters. The ultimate source for the deposit in Montana is challenging to understand; there are Precambrian (Archean) carbonates; the question would be are they of the right age and position to undergo the high grade metamorphism to produce a deposit like this? I don't know. And the processes that would sequester the carbon and re-deposit it in pure graphite are not evident to me - I guess if the metamorphic temperatures and pressures are high enough, more standard carbonates might not form and you'd be left with just graphite. I guess there are enough graphite occurrences worldwide that that could be the case, although it must be somewhat unusual. How all that fits with the idea mentioned in the post that the carbon dioxide is mantle-derived, I definitely do not know. I don't have access to this full article but it might be useful for your question: https://www.sciencedirect.com/science/article/abs/pii/0016703781900867
This might come across as a bit rant-e so apologies.
Basically what industrial compound or element isn't potentially "critical" when discussing electric vehicles and related "green" power generation and delivery. We couldn't pick a more problem laden topic than electrification of transportation (at least on the mineral supply side of the equation). Even when discussing one of the most abundant minerals, copper, that becomes a critical commodity, with occurrence and production limitations. All in the name of "green" pipe dreams.
On a more geological note, I tend to be in the camp that graphite in metamorphic rocks seem more likely be from carbonate protoliths, but the mantle-derived source is interesting.
No apology needed... the whole "this is critical" concept is to me just a political statement; most things either are, or should be, so globalized that they ought to just go from those who have to those who need. Yes, I know that's a total pipe-dream as well. My annoyance is mostly with the equivalent of the 'drill baby drill' idea, when the US fundamentally has zero of whatever the ignorant want us to not import from whoever is the enemy of the week. Call a thing critical all they want; irrelevant if Country X or Y is where most of it is located. And re the mantle source, I definitely do not understand that.
It's a pity that so many of those decisions fall into the hands of politicians and their staffers, the least likely to understand the consequences of their actions. The US has always lagged the rest of the world in general public understanding of even the most basic concepts of science or of base-level economics and even just general geography. It seems to be a loosing battle when approximately 50 percent of the US public believe that the Earth is only 5 thousand years old and dinosaurs coexisted with early man. For the politics, we get the governance what we voted for. For the ignorance, I despair the future (sort of, I'm not really that much of a curmudgeon, I just play on on TV). Cheers!
I took a photo of a nice graphite sample from Keswick museum in the English Lake District 2 weeks ago. The original "Black market" was the 18th/19th century smuggling business from the graphite mine in Borrowdale. Handling graphite makes your fingers black! The graphite was used for pencil making, the former pencil factory in Keswick is now its second museum. Also for making moulds for casting cannonballs. Perfectly spherical cannonballs make for more accurate navel gunnery so this was an important strategic material for the Napoleonic war and a contribution to Nelson's victory at Trafalgar. The graphite's in Ordovician volcanics with some regional metamorphism of Caledonian age - I've read that it's organic origin but didn't really believe that!
Thank you…I am wondering what geological processes are behind the deposits into fracture veins…hydrological, pressure?
Good question. I have the impression they come from high-grade metamorphism of carbon-bearing materials (like limestone and other carbonates) that makes the carbon evolve into carbon dioxide in solution, which precipitates from hydrothermal waters. The ultimate source for the deposit in Montana is challenging to understand; there are Precambrian (Archean) carbonates; the question would be are they of the right age and position to undergo the high grade metamorphism to produce a deposit like this? I don't know. And the processes that would sequester the carbon and re-deposit it in pure graphite are not evident to me - I guess if the metamorphic temperatures and pressures are high enough, more standard carbonates might not form and you'd be left with just graphite. I guess there are enough graphite occurrences worldwide that that could be the case, although it must be somewhat unusual. How all that fits with the idea mentioned in the post that the carbon dioxide is mantle-derived, I definitely do not know. I don't have access to this full article but it might be useful for your question: https://www.sciencedirect.com/science/article/abs/pii/0016703781900867
Thank you for the further information. I just read Beerling’s book on plants and CO2…the topic is very complex, indeed!
This might come across as a bit rant-e so apologies.
Basically what industrial compound or element isn't potentially "critical" when discussing electric vehicles and related "green" power generation and delivery. We couldn't pick a more problem laden topic than electrification of transportation (at least on the mineral supply side of the equation). Even when discussing one of the most abundant minerals, copper, that becomes a critical commodity, with occurrence and production limitations. All in the name of "green" pipe dreams.
On a more geological note, I tend to be in the camp that graphite in metamorphic rocks seem more likely be from carbonate protoliths, but the mantle-derived source is interesting.
No apology needed... the whole "this is critical" concept is to me just a political statement; most things either are, or should be, so globalized that they ought to just go from those who have to those who need. Yes, I know that's a total pipe-dream as well. My annoyance is mostly with the equivalent of the 'drill baby drill' idea, when the US fundamentally has zero of whatever the ignorant want us to not import from whoever is the enemy of the week. Call a thing critical all they want; irrelevant if Country X or Y is where most of it is located. And re the mantle source, I definitely do not understand that.
It's a pity that so many of those decisions fall into the hands of politicians and their staffers, the least likely to understand the consequences of their actions. The US has always lagged the rest of the world in general public understanding of even the most basic concepts of science or of base-level economics and even just general geography. It seems to be a loosing battle when approximately 50 percent of the US public believe that the Earth is only 5 thousand years old and dinosaurs coexisted with early man. For the politics, we get the governance what we voted for. For the ignorance, I despair the future (sort of, I'm not really that much of a curmudgeon, I just play on on TV). Cheers!
Agreed. I pretty much AM that much of a curmudgeon, much of the time.
I took a photo of a nice graphite sample from Keswick museum in the English Lake District 2 weeks ago. The original "Black market" was the 18th/19th century smuggling business from the graphite mine in Borrowdale. Handling graphite makes your fingers black! The graphite was used for pencil making, the former pencil factory in Keswick is now its second museum. Also for making moulds for casting cannonballs. Perfectly spherical cannonballs make for more accurate navel gunnery so this was an important strategic material for the Napoleonic war and a contribution to Nelson's victory at Trafalgar. The graphite's in Ordovician volcanics with some regional metamorphism of Caledonian age - I've read that it's organic origin but didn't really believe that!
Indeed, when I wrote about Borrowdale I could not find a satisfying origin for the graphite there - https://richardigibson.substack.com/p/c-is-for-cumbria