Alunite and Pyrophillite

Alunite and pyrophyllite are common in the alteration halos around sulphur rich epithermal gold and copper mineralization systems so learning to recognise them in the field is a useful exploration skill and understanding where they fit in these systems can help you vector towards the mineralized parts of the system. The full version of the video is part of the FieldCraft for Geologists course here:
geologyupskill.thinkific.com/...
Contents:
0:00 Alunite and Pyrophyllite in Epithermal Systems.
0:32 Infill Alunite
1:38 Alteration Alunite
1:55 Supergene Alunite
2:18 Pyrophyllite
3:29 Epithermal and Porphyry Systems

[@wiregold8930]

My ore deposits class was never this straightforward. I was constantly overloaded with minutia and struggled to grasp the big picture. You are an excellent teacher!

[@GeologyUpSkill]

Academic research, by it's very nature, seeks more and more detail for the chance to make a discovery that has not been covered by previous workers. Occasionally that pursuit makes spectacular discoveries in science, but we entrust those same people with training new geoscientists who need to understand the big picture before diving into the detail. Only a few of them are able to step back and remember what it was like to see a phase diagram for the first time.

[@ericjoseph2122]

I've studied alteration halo's but never knew this. 🤔 There's a big leap in geology in field and in classroom.

[@GeologyUpSkill]

That's exactly why I make these videos!

[@mineralresourceestimation9207]

The labels in the video rotate with the hand samples. Nice touch!

[@GeologyUpSkill]

Thanks. Davinci Resolve tracking is a useful tool!

[@nuel19]

Thanks you mister

[@javier090994]

Thanks a lot! I work with low sulphidation epithermal deposits and this kind of videos are really interesting for get a wider vision!

[@GeologyUpSkill]

Low sulphidation systems used to be thought of as a separate species, but it now appears that some of them are distal or evolved parts of the same fluid systems.

[@user-wl6gh5mi5e]

fantastic explanation, thank you so much

[@GeologyUpSkill]

Thanks. Fortunate to have such good examples!

[@rogelioneder8521]

Excellent video. Let's go for more videos like this. Congratulations!!!

[@GeologyUpSkill]

Thanks. The mineral ID videos do seem to be the most popular!

[@waltertodd4479]

Thanks again, so very much!

[@GeologyUpSkill]

Thanks Walter. Glad it helps.

[@manuelrengifo1017]

Well done. Thanks!

[@GeologyUpSkill]

Glad you liked it!

[@dolgorjavtogoo8237]

thank you very much dear

[@djamaluno5507]

Nice video,

[@GeologyUpSkill]

Thanks Djamal.

[@hagnier14]

Thank you for the video. Your video is really helpful. I'm currently doing a research about High Sulfidation Epithermal deposit for my final assigment but I still can't determine which one is alunite and which one is pyrophyllite during my field mapping.
I already took a lot of notes on how to describe and differentiate those 2 minerals from you video and I hope it'll be a very useful guide for me during my field work.
Keep up the good work sir 😁

[@GeologyUpSkill]

That's great. Hope it helps.

[@Utopiajessi]

Dear, could you share with me a clear image where the pyrophyllite and alunite, of advanced argillic, are observed, that is, when it does not look crystalline, please!

[@GeologyUpSkill]

The sample at 2:24 in the video is typical of pyrophyllite without obvious crystals in advanced argillic alteration systems. Alunite almost always shows some crystal reflections even when it is an alteration mineral (like the examples at 1:16), but they are much finer grained than the infill alunite in veins.

[@asmaravilhasdocriadoretern133]

Olá amigo excelente canal nova escrito gosto de pedras y conhecer mais os minérios !👍😉

[@laosgpsmapmidnitemapper9411]

Learning the (ropes) Rocks> excellent, lots of scratching around for Iron Ore between M Anuong past Phonsavon M Kham and M Hiem! Chinese want that Iron ore it seems, just uploaded some GPS maps for Lao Sanxia Minerals (Rio Tinto) mining seems to be opening up here

[@GeologyUpSkill]

Thanks Don. Should make some Lao geology videos in September.

[@rodrigopirainetravassos8899]

Muito bom!

[@GeologyUpSkill]

Thanks!

[@user-zg9jf4ft7p]

What is the benefit to know the alunite in the field?

[@GeologyUpSkill]

It commonly forms a halo around high sulphidation epithermal style gold deposits. That's a pretty useful guide!

[@danthelion4185]

is there a field test to distinguish sericite from pyrophyllite

[@GeologyUpSkill]

Sericite is basically a bucket term for white micas formed by alteration. Most of them have crystals large enough to see some reflections in the sunlight with a handlens, particularly on freshly broken dry surfaces. Even the really fine grained ones have a silky appearance that is different to the dull waxy sheen of pyrophyllite.

[@triminzimtriminzim1317]

Hi
I am failing to see the link for the topic you discussed on alunite alterations and associated gold copper deposits

[@GeologyUpSkill]

The link is in the video description, but I will put it here also geologyupskill.thinkific.com/courses/fieldcraft-for-geologists

[@alishafipourgeologist4520]

👌👌👌

[@runnikcatti5997]

I have a claim out in SW New Mexico. The old miners targeted white caliche-like patches to start the shafts. Are these hydrothermal or epithermal vents?

[@GeologyUpSkill]

It depends what the old miners were mining.

[@runnikcatti5997]

@@GeologyUpSkill Cu, Pb, Ag & Au

[@GeologyUpSkill]

@@runnikcatti5997 OK, so the white patches are probably indicating acid groundwater leaching due to weathering of sulphide in the veins. Not original hydrothermal vents, but a good exploration indicator!

[@margaretgould1521]

taking a walk with you could be very prosperous!, fancy a stroll?

[@GeologyUpSkill]

I should do more face to face training in the field!

[@jesse49046]

Interested in coming to lower Michigan?

[@GeologyUpSkill]

Have you seen something similar there?