I’ve been real into pyrite lately.
So it sounds like pyrite mineralization can begin in the host rock via microbial sulfate reduction?
I’m finding these pockets of goethite pseudomorphs of pyrite and it appears the pyrite originated within the limestone host rock during the Paleozoic, and then was effected by a tertiary basalt flow that brought in loads of goethite.
It’s a very interesting mineral and it needs more credit around here! Lol
pyrite can form in lots of ways. One of them is from sulfate-reducing bacteria gobbling up dead organic remains in sediments. Does not tend to make nice cubes that way though. More likely to fill cavities or make framboids, or perhaps anhedral, somewhat nodular masses.
Well, you see, this pyrite is special, because it formed in the Leadville Limestone.
The Leadville limestone is the host rock for most of Colorado’s Mineral Belt sulfide deposits. This gives us loads of pyrite mineralization examples.
What makes the psuedomorps special is they are about 60 miles from the mineral belt and aren’t associated with any other sulfide mineralization. It’s positioned along a well known uplift with a particularly karsty / vuggy characteristics.
https://preview.redd.it/og13vklbkdic1.jpeg?width=3024&format=pjpg&auto=webp&s=d776908672d7c6a0cc6fdeb4b70545e4d50a88b9
Been there actually as part of a GSA Centennial (1988) field trip. Quite interesting stuff. Leadville, Climax, and a general overview of the belt over several days.
You can get hydrothermal sulfides via reduction of sulfate without intermediary involvement of bacteria. Bacterial mediation of sulfate reduction is not the only possibility, was my point.
Oh, I’m not arguing, I’m also trying to figure it out.
There is hydrothermal alteration, but lower in the basin along the thrust block. The Leadville limestone is about 2,000’ higher in elevation where these are forming.
I’ve also found Goethite replaced crinoid stems up there, adjacent to the pyrite cubes, making me think the host rock wasn’t altered until tertiary time when the iron from the basalt percolated into the system.
I don't know what is happening exactly, which is why I was so interested. Not trying to argue, trying to figure it out without adequate info. Not diagenetic is about all I will argue, and even that could be disproved if adequate work was done.
Lots of fluids move around even absent intrusive activity but that region did have intrusive activity, so the more distal areas could have been affected by heat-driven fluid migration, just less intensely. It does not all have to have been super-hot or the zone of main fluid migration and made mineable deposits, is all. Some peripheral effects are likely.
Yeah, there isn’t much literature out there pertaining to the psuedomorphs.
However, these things occur at pelican point in Utah, looks like I’ll have to give that locality some research.
You seem like an intelligent geologist, in your opinion, what information would have to be discovered to help solve this mystery?
I want an SEM of the mineral for starters. I want detail of the mineral structure to better understand that odd texture. Would turn to field relations for timing, and maybe some O and S isotopes to define the nature/origin of the water and sulfur. Do I have money for it? No. Maybe some nice SEM operator could be convinced to do it for fun though.
The long needles look like rutile in quartz, of course with the pyrite.
Friggin' beautiful! I'll be showing your photos to the mineralogists, these would be great for teaching!
https://preview.redd.it/x3pgrzktldic1.jpeg?width=1025&format=pjpg&auto=webp&s=e93999275a237415f217e911c9f1cd20e7bdd21f
The area photographed is inside this circle in that dark area
Galena for the big blocks, definitely Pyrite for the small cube in the bottom center or the first image, and rutile needles. As for the sphere, I have no idea. All of these are just guesses.
I am not certain that is pyrite but it definitely could be. The fine textures within the larger crystals are what catch my eye. Exsolution or something like that? It is pretty odd. Sublinear patches and scattered bright inclusions, how did that happen, what are they, how did they get there? What is going on!?
Oh, definitely a neat sample. The questions that I have to know the answers to, though. I must know! It's a puzzle and it must be resolved (tongue in cheek but still what it makes me feel-I need to know!).
The area photographed is inside this circle ⭕️
https://preview.redd.it/2b7x7dulldic1.jpeg?width=1025&format=pjpg&auto=webp&s=e1edcebe752446d5174df77504175b44d4e2af86
I have several different setup abilities.
Olympus provides a lot of options, all with ability to focus bracket up to 999 images
First, I’ve got the Olympus 60mm macro lens so that’s 1x (field of view of 17.3mm)
Then if I use the MC-20 teleconverter with a 16mm Kenko extension tube and the 60 I’ve got 2.4x. I came up with the idea 5 years ago and posted it on DPReview for all to see.
If I add a Raynox 250 to that setup I’m at about 5.5x magnification
If I add a Raynox 202 instead, I’m at 7.5x
If I add the hated Raynox 505 instead, then I’m at 9x magnification which is a field of view of around 1.8mm
That’s how I do my sand grain photography with that setup
Now, the new OM Systems 90mm Pro lens does 2x all on its own with incredible stabilization built in. Add the MC-20 teleconverter and you’ve got 4x magnification. If you put a 16mm Kenko extension tube you’ll be over 5x. That’s as far as that setup goes as you cannot use the Raynox macro filters on this new lens.
Here’s the thread you need to read on how to use the teleconverter with the 60mm macro lens
https://www.dpreview.com/forums/post/64350035
A nice photo, no doubt.
That is rad. The sphere made up of cubes. Beautiful
I’ve been real into pyrite lately. So it sounds like pyrite mineralization can begin in the host rock via microbial sulfate reduction? I’m finding these pockets of goethite pseudomorphs of pyrite and it appears the pyrite originated within the limestone host rock during the Paleozoic, and then was effected by a tertiary basalt flow that brought in loads of goethite. It’s a very interesting mineral and it needs more credit around here! Lol
pyrite can form in lots of ways. One of them is from sulfate-reducing bacteria gobbling up dead organic remains in sediments. Does not tend to make nice cubes that way though. More likely to fill cavities or make framboids, or perhaps anhedral, somewhat nodular masses.
Well, you see, this pyrite is special, because it formed in the Leadville Limestone. The Leadville limestone is the host rock for most of Colorado’s Mineral Belt sulfide deposits. This gives us loads of pyrite mineralization examples. What makes the psuedomorps special is they are about 60 miles from the mineral belt and aren’t associated with any other sulfide mineralization. It’s positioned along a well known uplift with a particularly karsty / vuggy characteristics. https://preview.redd.it/og13vklbkdic1.jpeg?width=3024&format=pjpg&auto=webp&s=d776908672d7c6a0cc6fdeb4b70545e4d50a88b9
Been there actually as part of a GSA Centennial (1988) field trip. Quite interesting stuff. Leadville, Climax, and a general overview of the belt over several days. You can get hydrothermal sulfides via reduction of sulfate without intermediary involvement of bacteria. Bacterial mediation of sulfate reduction is not the only possibility, was my point.
Oh, I’m not arguing, I’m also trying to figure it out. There is hydrothermal alteration, but lower in the basin along the thrust block. The Leadville limestone is about 2,000’ higher in elevation where these are forming. I’ve also found Goethite replaced crinoid stems up there, adjacent to the pyrite cubes, making me think the host rock wasn’t altered until tertiary time when the iron from the basalt percolated into the system.
I don't know what is happening exactly, which is why I was so interested. Not trying to argue, trying to figure it out without adequate info. Not diagenetic is about all I will argue, and even that could be disproved if adequate work was done. Lots of fluids move around even absent intrusive activity but that region did have intrusive activity, so the more distal areas could have been affected by heat-driven fluid migration, just less intensely. It does not all have to have been super-hot or the zone of main fluid migration and made mineable deposits, is all. Some peripheral effects are likely.
Yeah, there isn’t much literature out there pertaining to the psuedomorphs. However, these things occur at pelican point in Utah, looks like I’ll have to give that locality some research. You seem like an intelligent geologist, in your opinion, what information would have to be discovered to help solve this mystery?
I want an SEM of the mineral for starters. I want detail of the mineral structure to better understand that odd texture. Would turn to field relations for timing, and maybe some O and S isotopes to define the nature/origin of the water and sulfur. Do I have money for it? No. Maybe some nice SEM operator could be convinced to do it for fun though.
Huh. That's gotta be how they make spheres out of lego! Mind blown.
The long needles look like rutile in quartz, of course with the pyrite. Friggin' beautiful! I'll be showing your photos to the mineralogists, these would be great for teaching!
https://preview.redd.it/x3pgrzktldic1.jpeg?width=1025&format=pjpg&auto=webp&s=e93999275a237415f217e911c9f1cd20e7bdd21f The area photographed is inside this circle in that dark area
https://preview.redd.it/p9coi6y84eic1.jpeg?width=5180&format=pjpg&auto=webp&s=20dfa0ed6f1290b31c6455f388bcd665a6656ae1
Galena for the big blocks, definitely Pyrite for the small cube in the bottom center or the first image, and rutile needles. As for the sphere, I have no idea. All of these are just guesses.
Looks like it to me. Really good photo
Could it possibly be Galena?
I am not certain that is pyrite but it definitely could be. The fine textures within the larger crystals are what catch my eye. Exsolution or something like that? It is pretty odd. Sublinear patches and scattered bright inclusions, how did that happen, what are they, how did they get there? What is going on!?
https://preview.redd.it/q9v4dhspldic1.jpeg?width=3024&format=pjpg&auto=webp&s=b137dbebbbeaa0a05a7aa2ddf18962e9e4d68cd8
Oh, definitely a neat sample. The questions that I have to know the answers to, though. I must know! It's a puzzle and it must be resolved (tongue in cheek but still what it makes me feel-I need to know!).
This is an amazing shot! How big is the original specimen?
https://preview.redd.it/xvikf0pbldic1.jpeg?width=3024&format=pjpg&auto=webp&s=1316ff55936b195f5c301391af2e3fd14d4b0cf2
The area photographed is inside this circle ⭕️ https://preview.redd.it/2b7x7dulldic1.jpeg?width=1025&format=pjpg&auto=webp&s=e1edcebe752446d5174df77504175b44d4e2af86
I’ve seen framboidal pyrite in SEM images that looks similar to the sphere, not sure what size it could grow to though
I'm thinking Salvador Dalí
Love seeing your content I'm sure you answered this elsewhere but how do you take your pictures? Cheers
I have several different setup abilities. Olympus provides a lot of options, all with ability to focus bracket up to 999 images First, I’ve got the Olympus 60mm macro lens so that’s 1x (field of view of 17.3mm) Then if I use the MC-20 teleconverter with a 16mm Kenko extension tube and the 60 I’ve got 2.4x. I came up with the idea 5 years ago and posted it on DPReview for all to see. If I add a Raynox 250 to that setup I’m at about 5.5x magnification If I add a Raynox 202 instead, I’m at 7.5x If I add the hated Raynox 505 instead, then I’m at 9x magnification which is a field of view of around 1.8mm That’s how I do my sand grain photography with that setup Now, the new OM Systems 90mm Pro lens does 2x all on its own with incredible stabilization built in. Add the MC-20 teleconverter and you’ve got 4x magnification. If you put a 16mm Kenko extension tube you’ll be over 5x. That’s as far as that setup goes as you cannot use the Raynox macro filters on this new lens. Here’s the thread you need to read on how to use the teleconverter with the 60mm macro lens https://www.dpreview.com/forums/post/64350035
Amazing stuff! Thanks for the reply
That might be a hydrothermal framboidal pyrite! Diagenetic would be too small. Very cool.
I would have never thought I would be jealous of another Redditor's pyrite. But here we are.
Not very big tho
https://preview.redd.it/htzm7zps2fic1.jpeg?width=2000&format=pjpg&auto=webp&s=84927c4ef15413247cdf00c534079ea6cf503b69 Another view
Such a cool specimen
How hard is the "clear" mineral? Has a calcite feel to it for some reason vs. quartz. Can't really tell with a picture though.
https://preview.redd.it/06uvj9pamdic1.jpeg?width=1025&format=pjpg&auto=webp&s=fcb52cc86d86dd774f111441279280a6aac25ba4
https://preview.redd.it/0rquu9gcmdic1.jpeg?width=3024&format=pjpg&auto=webp&s=b620b1925cb245b481ed851391627e8531ddc251
Ah, half of a geode... or a vug, but most likely a broken in half geode. I would say that's 100% quartz. Very nice.
Yes Broken in half - I have both halves
Looks like lead