Gabbro?

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Gabbro?

Post by flyrock on Sun 01 Mar 2015, 1:31 pm

Hi all

Has anyone specifically targeted altered structure/faults/folds on Gabbro (Abg) geology for gold?

I am interested on peoples views, as I have identified a few places of interest with no historical gold found.

The locations are a fair step off formed roads/tracks, so I thought I'd get as much info as possible before heading off into the yonder!

Cheers

Phil

flyrock


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Re: Gabbro?

Post by Metamorphic on Mon 02 Mar 2015, 1:09 pm

Hi flyrock and this is an interesting question.

I have always targeted faults and sheer zones that exist in Metamorphic rock as the foliated structure of this strata type is perfectly conducive towards the conditions of primary gold formation (crystallization of minerals from a saline soluble state).
Gold is not particular about its host rock, but its usually found in quartz among metamorphosed zones because the structure in these zones is right.
Here i speak mainly of Mylonite, Schist, slate and Gneiss

Gabbro being an intrusive Igneous rock, it doesn't provide foliation channels for fluids to flow within and become trapped, however the faults/sheers would provide for this no doubt if the structure was right.

Gold is known to form among intrusive igneous like Granite, so i dont see how Gabbro would be any different.....possibly even better as it is actually an ancient seabed strata and is the Plutonic version of Basalt.

Have you done any testing on samples of the area so far? Both soil loam and rock crushings?

I would be looking for other clues also such as changes in ground conditions, vegetation, mineralization amounts etc.
Testing is the best sure fire way to tell if there is gold in the vicinity in my view!

Cheers!


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There is no better indication of a lot of gold, than a little gold - Sam Cash
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Metamorphic


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Re: Gabbro?

Post by flyrock on Mon 02 Mar 2015, 4:39 pm

Thanks for the info Metamorphic.

I'm heading off for a look in the next two weeks, so will do some loaming, chip sampling on contacts (for crushing later) and tecting. I will post my results on my return.

Cheers

Phil

flyrock


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Re: Gabbro?

Post by farm boy on Fri 13 Mar 2015, 10:49 am

Hi Phil and metamorphic.

I too was just wondering would alluvial be found around gabbro?? I have a likely spot of contact of gabbro (aog) and metamorphosed basalt (Abm). There is a shaft right on this contact and has a anticline pass through it. Could one hope for coarse alluvial in this type of geology? Cheers fb


farm boy


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Re: Gabbro?

Post by Metamorphic on Mon 16 Mar 2015, 11:48 am

Hi fb

If there is a shaft on this contact, then someone was chasing primary reef deposits.

They would not have dug the shaft without positive testing results of some form.

Contact zones where the metamorphic meets igneous can form natural traps for the fluids travelling along the foliation lines, faults etc.

Now we all know that reef gold sheds over time from weathering and erosion so it is logical to expect alluvial to be carried down into the lower reaches of the general area.

Take a pan, and do some testing of your own fb. If you get color, you will know if its worth further investigation.
The right geological makeup does not always guarantee gold but it sure makes for a odd stacking possibility in your favour.

Cheers


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There is no better indication of a lot of gold, than a little gold - Sam Cash
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Metamorphic


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Re: Gabbro?

Post by farm boy on Tue 17 Mar 2015, 11:32 am

Cheers Metamorphic. Really Appreciate the info.

I also noticed a concealed mafic dyke cuts across exactly where the shaft is on this contact. Presumably this assists primary gold formation? Will definitely do some panning and detecting
Cheers FB


farm boy


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