Orogenic Gold Deposits

Dr Richard Goldfarb is a world expert on Orogenic Gold Deposits. He explains how orogenic gold formed during plate tectonic collisions and especially during continental growth. See more films about gold deposits at GEOLOGY FILMS Channel goo.gl/0mw8Z4

[@hughjackson218]

Absolutely LOVE this channel! Shame there aren't many uploads.

[@Christh2008]

Thanks for fantastic films. I have just completed my 2nd year geology subjects as a mature aged student at Monash and my passion is gold Geo particularly Victoria, so this film is right up my alley. Thanks so much, this film has helped me to order the general geo theory I've learned up to date, i.e. plate tectonics, metamorphism and chemical origins and how they interact to make orogenic deposits. Thanks Heaps and keep up the great work :)

[@mahmoudhamed1459]

I am about to graduate, and I have the same passion. I hope that you achieve what you want :)

[@secretstreamsandfeverdreams]

Have just discovered your channel, absolutely brilliant! I have no formal education and often have to research certain terms, but I still find your films highly engaging and informative. Thank you so much for these wonderful films!

[@GeologyFilms]

Thank you very much.

[@terrylegrosbisson1177]

Haha, my comment was very similar to your own, I didn't even see what you had written

[@Giavani-t4k]

Excellent presentation.

[@stephenmitchell243]

Richard Goldfarb is my idol! He is the most knowledgeable geologist on the planet!

[@ronnieboucherthecrystalcraftsm]

i bet you he has never found GOLD !

[@grendel_nz]

Cute, for sure 😊

[@audigga4396]

I am just an average part time prospector...I found this very informative ...heading out tomorrow to get rich....with Australian outback culture :)

[@GamingKeenBeaner]

I have learned so much from this channel! Thanks

[@GeologyFilms]

Thanks for your comment

[@gavinherbert]

Please make more vids, just EXCELLENT!!!

[@SIZModig]

Dr. Goldfarb, the gold specialist - now that's a job he was born for.

[@Townz88]

Great films!

[@terrylegrosbisson1177]

I just discovered your channel, I clicked on subscribe after watching the first video I saw, congratulations on a really informative channel

[@harrietharlow9929]

Another wonderful film. I found you recently and your channel is a great resource for those interested in geology. Thank you for uploading!! Australia is such a fascinating place and nowhere is this truer than in its geology.

[@GeologyFilms]

Thank you for watching and encouragement.

[@harrietharlow9929]

@@GeologyFilms You're very welcome!

[@g-dcomplex1609]

discussing the four orogenies and subduction zones is a turn on, to a geologist

[@GeologyFilms]

Thanks for the comment and yes I'm planning more films for 2014

[@makeithobbyncraft2329]

Excellent presentation

[@loveofit6498]

Thanks for sharing this.Very interesting!

[@frankbyrd6726]

Thank You ! Very interesting and well presented , hope to see many more vids

[@santiagoberrioscorrea6487]

Excelente canal, muchas gracias

[@rosscayley8773]

Excellent Clive, and good to see the Piper Creek Syncline gets a guernsey!

[@goldhunterexploration-shei5873]

Very informative

[@Sarah-zb]

what a great video and an amazing channel !! i hope you will continue making such informative videos in the very near future.

[@GeologyFilms]

Thank you very much for your support.

[@DANVIIL]

Fascinating.

[@skgems1558]

very informative videos and will be looking forward for more. thanks.

[@paularowe7651]

Very interesting. I worked back in the 1980 s for RTZ on mineral exploration in the UK.

[@GeologyFilms]

Thank you for watching

[@illumencouk]

H - I read you're post with interest. Any advice on where the more interesting locations are found in the UK? Any observations or tips you picked up?

[@christineatherton3572]

Thank you

[@josoapification]

The gold baring quartz in the dalradian gold mine in the sperrin mountains in the north of Ireland are exactly the same. The sample I have has more visible iron pyrite than gold. The mine doesn’t give you the bits with lots of gold in them.

[@lionelbonhomme4650]

worth my time .

[@Rockhounding-with-Bigfoot]

make more!!

[@darrenknight443]

awesome,

[@premalalmendis4967]

Hi Richard, I'm looking for the chemical equations associated with gold formation during retrograde metamorphism of pyroxenes to amphiboles. Do you think you can help me! Many thanks.

[@luckyja1]

Can you tell me the specific location of eastern Victorias fault line?

[@krisj9139]

I want to see more of that Big gold he had on the table

[@user_mac0153]

A fine scientific specimen to be sure to be sure.

[@papkee4587]

Any possibilities to find any english subtitles ? PS. nice and very informative movies. looking forwardfor more videos. :)

[@GeologyFilms]

+papkee Thanks for your good suggestion. I have added English subtitles to this film and will do the same for all the others soon.

[@anisejones8488]

So what type of rock acts as the source of the gold found in orogenic gold deposits?

[@GeologyFilms]

Thanks for your question. Many researchers, like Iain Pitcairn, think that oceanic sedimentary rocks are the best source of gold - particularly sediments with a high carbon content and containing diagenetic pyrite - that is pyrite that has formed on the seafloor. But there is also evidence that oceanic basaltic rocks could provide a good Au source. For example, very thick packages of basaltic rocks are interbedded with sedimentary rocks under the very rich Victorian goldfields in SE Australia.

[@bryguy636]

I'm wondering if there is any relationship to the way opals are formed?

[@michaelmacgeorge1082]

Volcanic activity can create hydrophane opal, but sedimentary opal is much better.

[@dave9351]

All right, let's have a small discussion about those gigantic nuggets that the person filming slowly shows us during this discussion of "orogenic gold deposits" ! How much to those boulders, not nuggets weigh ?

[@GeologyFilms]

They are models of real nuggets

[@pasblan1]

le processuse et differant

[@pasblan1]

le processuse et differant

[@pasblan1]

oui met la geologie du yukon tate de fin air graciere

[@illumencouk]

Err Excuse me. Did I miss something? "So where does gold come from?" was the question and while I heard things like 'metamorph' and 'injects' I can't recall anything that scientifically indicated how the gold initially came to be in the ground. I assume the metamorphosis you mention is not demonstrable in the laboratory?

[@GeologyFilms]

Rich briefly answers this at about 3:51. There are low levels of gold in marine sedimentary rocks - usually in concentrations of parts per billion. Some shales that have formed in an oxygen-poor environment contain a lot of pyrite and this pyrite can have a relatively high Au content. The processes of metamorphism are quite well understood and and I'm sure that lots of lab experiments have been done over the years. The theory is that hydrated seafloor rocks, when metamorphosed to about 350 degrees C, will release the water that was contained in some minerals. The hot water then scavenges gold from the surrounding rocks.

[@illumencouk]

@@GeologyFilms I'm not doubting for one moment that trace amounts might migrate together, but we're talking such low amounts over a ridiculous amount of time that it's unlikely. Feasible but unlikely.

[@zytigon]

I first saw Dr Richard Goldfarb on the excellent "How the Earth was made" series by History channel. Amusing play on words Rich Gold farb. He was down a gold mine looking at a white quartz seam with visible gold nuggets in it. , is it a pen name ? On another geology video there was a geologist called Prof Underhill.

[@therrienmichael08]

I've seen Dr. Goldfarb somewhere. it must have been History Channel or another KZbin video.

[@jefferyindorf699]

Prof. Underhill is the penname of a Hobbit named Frodo Baggins. 😉

[@pasblan1]

le processuse et le maime que a nome alaska

[@pelletierjocelyn5564]

Epithermal deposits are formed by granitic magma... really? And 400C is not enough to deslfurised the auriferous pyrite...

[@wantonfuey1]

"Rich Goldfarb"...is actually his name :)

[@GraemeWight-wx3xz]

That guy is freaky

[@Jesse-cw5pv]

I thought his name was 'Rich Goldfarm' and he farmed gold lol. I mean his name is 'Rich Goldfarb' so it's kinda close

[@Rijaswaan]

Please be my place my guest

[@DragonHeartTree]

Interesting. But doesn’t explain why gold is so often found alongside radioactive minerals such as uranium. Last I heard, all attempts to create gold in a lab have produced radioactive samples. Coincidence? How fast do those radioactive gold products shed their radioactivity I wonder...

[@smiljanicn]

What my friend thinks I’m doing as economy geo. :)

[@richardrobertson1331]

Love your video. But when you say: "There's no doubt about it.", I cringe a bit. Discovery and science requires everything be repeatedly questioned. When you displayed that very thick vein of quartz, there were several thin layers of black host rock contained in it running parallel to the vein. To me that indicates possibly that this vein broke away (additional earth quakes) from the wall rock repeatedly over time, sometimes taking a small amount of host rock with it. Quartz is less elastic than most host rock plus there is little bonding to the host rock, so the quartz repeatedly fractured permitting deeper hydrothermal fluids under greater pressure, to be pushed up with their dissolved minerals. New fractures in the quartz and on its boundaries permitted additional quartz/gold/ iron sulfide, etc., to precipitate if it were moving slowly enough as the pH, temperature and pressure changed. So one vein of quartz may have had a hundred or more episodes of growing. Earthquakes thus became the gold miner's friend, in time. Additionally, if the upper environment did not encourage mineral precipitation, it's possible some of the existing quartz vein and minerals already deposited may have been re-dissolved and moved even higher.