Fake Gossans and How to Spot Them
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- Опубліковано 1 січ 2021
- The full video and others in the course Fieldcraft for Geologists are here:
geologyupskill.thinkific.com/...
Almost any rock composed of residual iron minerals can be called a gossan, but mineral explorers are generally only interested in the ones created by the weathering of sulphide. This video is a guide to telling the difference between the gossans after sulphide and all the other types.
Good! Thanks proffesor
Thanks. Much appreciated.
Love your content, thanks for sharing!
Thanks for watching. Hope my videos inspire a few more people to enjoy rocks!
Nicely done, Nick. Another "trap for young players" that is worthy of mention (I caught out one of my young geos recently with this) is the lateritic ferricrete, especially in tropical terrains where the intense erosional regime may leave partial, degraded or even false linear outcrops of the stuff. It might also be worth mentioning the variations in gossan between arid environments (where much of the "goodies" are retained and those in the tropics where even the quartz may be weathered to whitish snot. Cheers mate. Keep them coming; I have a plan to make your videos compulsory viewing for my team.
Thanks James. Yes I have seen those Pseudo linear ridges too. They can be a pretty good fake at times!
I doubt there is any case where quartz is weathered to whitish snot. You can take Permian geodes from Germany and get perfect agate cores while the shells are kaolinized white from decomposed feldspar. The quartz is untouched.
Major nickel deposits of the world come from tropical soil laterites. And bauxites for aluminum.
A good presentation from Nick on gossans.
In relation to a previous video, I dont like a mag sus unit noted as a sex toy but Ive moved on 👍
I would suggest from memory - Blanchard, interpretation of leached outcrops and of course Roger Taylors book.
Yes, Blanchard is the seminal text on this subject. Roger Taylor's book has an exceptional set of photographs that illustrate the concepts.
Thank you for this video
My pleasure. Glad you found it useful.
Thanks for the video, I have observed a similar intrusion between metasediment looks like that "not good one" you have mentioned.
So, what would it be! Very confusing to me
If it is parallel to the ground surface, it is likely to be a laterite horizon. If it is steep dipping then it might be secondary iron oxides precipitating in a fault parallel to bedding. Both are pretty common.
thanks you for the video. you know where i can find more information about gossan after garnets ? it would be very useful for me, thank you again.
The book I mentioned in the video (by Roger Taylor) has some information and some really good pictures of garnet gossans.
Muito legal!!
Wonderful Videos it’s the really genuine presentation of the information. Bravo 👏
Thanks. I try to leave out the padding and stick to the useful stuff.
@@GeologyUpSkill I live in Seattle always have been a rock hound. Then during Covid I filled the time with a local teacher Nick Zentner
ua-cam.com/video/jm-g-p08e24/v-deo.html
@@BudKnocka The other Nick is probably the most famous (and prolific) geologist UA-camr.
Thanks for your content. It would be even better if your courses are subtitled in other languages, such as Spanish
Thanks Bruno. You should be able to get Spanish subtitles in UA-cam by turning on Closed Captions (CC) then go to settings and set the language Spanish.
Thank you for the explanation. I have a question. What is the special thing from gossan that are from weathering of sulphide so mineral explorers love and like to find it?
This video has a summary of the things that indicate sulphide. If you would like the detail on each of the points (and all my other videos), then I recommend that you sign up for the full course at: geologyupskill.thinkific.com/courses/fieldcraft-for-geologists
In a vent such as a volcanogenic massive sulfide (VMS) the key indication are the aureoles or large scale zoned rings of mineralization. Outer rings are barites and banded quartz. Inner rings are sulfides. Cores are heavy metals. The caprocks are not just "weathered sulfides" but we call them jaspers, siliceous dark brown rocks with banded layering, often also with reds and yellows.
Good !
Gossans are good!
Is that ulteramafic goasans is listwanite body?!
The sample that I'm holding at 2:50 might actually be a gossan after listwanite. It is certainly from an oxidised ultramafic outcrop, but there is no fresh part exposed to see how much carbonate was in there.
What is a good prism to identify good rocks
I use a Bausch and Lomb 10x handlens. They are quite expensive, but when you use it 100 times a day, you appreciate the quality.
@@GeologyUpSkill What is a good way to extract gold from this type of rock. 1 cyanide 2 Furnace in the crucible
what is difference between Gossan and Latterite?
Gossan is the result of oxidation and leaching of iron rich primary minerals (usually sulphides, but also carbonate and a few other minerals). Laterite is a type of soil profile that develops by precipitation of iron oxide minerals from ground water. Laterite can form over almost any primary rocktype so it is not particularly useful as an exploration indicator.
@@GeologyUpSkill Thank you sir
@@GeologyUpSkill Thank you Sir! for your costly words
So what would fake gossans actually be called?
Laterite mostly!
Neat. Did not mention ferricretes, often mistaken for real gossans. Cheers.
Actually some of the goethite rich fake gossans in this video are from a ferricrete horizon that is part of a dissected laterite profile.
@@GeologyUpSkill Wouldn't discount goethite/hematite as being an accessory in a gossan rather than a fake gossan.😀
@@wayneperry7027 Yep. The combination of mineralogy and textures has to be taken into account.
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