Secondary Biotite Alteration

Secondary biotite alteration is difficult to recognize but it is one of the most important alteration minerals because it is commonly associated with ore zones in large IOCG and porphyry mineralization systems.
The full Fieldcraft for Geologists series is here: geologyupskill...

[@hutchinsonsolarlunarplanet538]

CANNOT GET ENOUGH OF THIS CHANNEL!!!! I just learned something yet again!!!!

[@GeologyUpSkill]

Great! My job is done!

[@hutchinsonsolarlunarplanet538]

@@GeologyUpSkill You are the "Ben Kenobi" of Geology on KZbin my master!!!!

[@GeologyUpSkill]

🙏

[@alexandersmith8016]

I’ve recently found your videos, and I have to say, they’re very insightful! Your explanations are to the point and easy to digest. Cheers!

[@GeologyUpSkill]

Thanks very much. I try to condense complex concepts into relatively simple rules of thumb that can be used effectively in the field.

[@ericjoseph2122]

I'm learning more from you than my university.

[@GeologyUpSkill]

Thanks Eric. I am trying to make videos about the stuff that we learn by experience rather than study.

[@FelipeOrtiz1012]

Me too

[@downsouth5447]

Cheers Nick, I find distinguishing/categorising various alteration types one of the harder aspects when field mapping

[@GeologyUpSkill]

It is tricky and it also masks the original rocktypes, but it is imprtant to sort it out because alteration facies are the footprints of hydrothermal systems and they make orebodieis!

[@kk-fc3yd]

@@GeologyUpSkill how much do you rely on thin sections to make final calls about interpretation

[@retrobitgarage7497]

thanks for the video, cheers..

[@meilani-2163]

Thank you! your videos are helpful

[@GeologyUpSkill]

Thanks for the comment. Every one helps KZbin find more people who could use the information.

[@manuelrengifo1017]

Great video Mr Nick. I really would like understand better your explanation, unfortunately, I just speak Spanish and just understand a little of English. Subtitles button writes really bad or simply writes nothing. I´m wondering if you could help to Spanish speakers to understand better, could be with subtitles editing by you or your team, or maybe speaking slowly (hehehe, sorry, I really would like understand completely all your videos), it will be really great. Thankyou sincerely for your job and your time to share your experience freely with us, congrats and best wishes for you. Viva la geología, saludos!!!

[@GeologyUpSkill]

Estoy sorprendido por eso. Probé los subtítulos en inglés y la transcripción automática de mi voz es casi perfecta. Este español lo genera Google Translate y suele ser bastante bueno de inglés a español.

[@manuelrengifo1017]

@@GeologyUpSkill Great, thank you very much for your response. Regards

[@GeologyDude]

Cool!

[@GeologyUpSkill]

Thanks!

[@douglasheineckleaes1629]

Hey Nick, great video. All of your content, and topics, exposure the beauty of field gelogy, so thanks for that. I'm wondering, the examples of secondary biotite in this video are in any instance related to contact metamorphism? I'm working with contact metamorphism in a Neoproterozoic meta- volcanosedimentary unit, located in southermost Brazil and we came across a bunch of biotite, chlorite, muscovite and actinolite with these kind of texture, and microstructural, relations. Desoriented, porfiroblastic... but we could also observe metamorphism in the matrix (granoblastic), don't know if it's the case on your video, could not tell by the image on the video. It would be nice to hear from you about it.

[@GeologyUpSkill]

It is possible to make randomly oriented biotite with thermal metamorphism (without hydrothermal fluid), but you need a source of potassium in the rock. That's easy in a granite or sediment but not so much in a diorite. The other clue is evidence of fluid channelways (like the hydrothermal breccia in this video).

[@Taste_Buds_Watery]

Super...

[@deepinearth7265]

I think the secondary biotite is one of the main indication that how "KISLADAG GOLD MINE" discovered in Turkey.

[@GeologyUpSkill]

It is indeed, and that is a common association in "porphyry" type copper and gold deposits.

[@leonardorodriguez3363]

How biotite alteration form?

[@GeologyUpSkill]

Potassium rich hydrothermal fluids at relatively high temperatures reacting with iron rich minerals, so it is pretty common in the early stages of Porphyry Cu and IOCG type systems.

[@glenwarrengeology]

Look at all that extiction, I wish Avocado would be extinct.

[@jdean1851]

GREAT INFO" THANX!