Is This A Reef?

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shakergt

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For those who know better than me is this a reef at the top of the picture in the middle? I am unsure but it is czl ground and runs east west

1594038342_capture.jpg
 
most gold bearing reefs run north - east or within 18 degrees of it.

however plate movement could have twisted one around to be west-east

it could be a rock wall built by a welsh farmer ?
 
Nightjar said:
WA deposits are generally North/South and reefs run East/West. eg: Kalgoorlie/Menzies/Leonora, with other minesites inbetween.

Should we differentiate between locations of reefs and earth fault lines ?

What is the rule for categorising the difference between them ?
 
Nightjar said:
WA deposits are generally North/South and reefs run East/West. eg: Kalgoorlie/Menzies/Leonora, with other minesites inbetween.

Nightjar this area is in the west australian goldfields. Also there is a fault line about 100m to the north of the area I have taken the shot of. Just to south west of this location out if shot I have taken around a ounce and a half in the past in sub grammars. So I know the area does produce
 
CreviceSucker said:
Nightjar said:
WA deposits are generally North/South and reefs run East/West. eg: Kalgoorlie/Menzies/Leonora, with other minesites inbetween.

Should we differentiate between locations of reefs and earth fault lines ?

What is the rule for categorising the difference between them ?

I'm not a rock doctor, but reefs and fault lines are completely different things.
Quartz reefs formed aeons ago when silica-rich volcanic fluids were forced up through rock and solidified.
Fault lines are surface expressions of deep crustal weaknesses, where rocks have cracked as a result of movement by either side of the fault.
 
My opinion/assessment (for what it's worth) is "maybe".

Although the general geology runs NNW/SSE in WA in reality on the micro level it can run in any direction. Also, remember erosion......we have had 10km above us wearing down over the last 2.5 billion years or so and what is to say a lump of qtz the size of an aircraft carrier hasn't decided to stop right there?

I have often found so called reefs that are actually big lumps of qtz that are disintegrating over time and spreading out in a line.....I call them pull ups...don't know why...just what I call them.

I wouldn't worry too much about using a geo map....they are constructed by people and often incorrect. Walk out of strike for several hundred metres and see if it continues.

Ultimately, I assume you want to know if it carries?? Sample...sample and more sampling....if the ground is yours OR you can gain control of it...otherwise your just wasting your time.
 
Goldtalk Leonora said:
My opinion/assessment (for what it's worth) is "maybe".

Although the general geology runs NNW/SSE in WA in reality on the micro level it can run in any direction. Also, remember erosion......we have had 10km above us wearing down over the last 2.5 billion years or so and what is to say a lump of qtz the size of an aircraft carrier hasn't decided to stop right there?

I have often found so called reefs that are actually big lumps of qtz that are disintegrating over time and spreading out in a line.....I call them pull ups...don't know why...just what I call them.

I wouldn't worry too much about using a geo map....they are constructed by people and often incorrect. Walk out of strike for several hundred metres and see if it continues.

Ultimately, I assume you want to know if it carries?? Sample...sample and more sampling....if the ground is yours OR you can gain control of it...otherwise your just wasting your time.

Thank you for the advise Goldtalk Leeonora. It is definitely worth a look then. Lucky for me I have got permission from both the mining company and the station owners where this lease is and I am welcome anytime. unfortunately I will never get control of that land.
 
Nightjar said:
WA deposits are generally North/South and reefs run East/West. eg: Kalgoorlie/Menzies/Leonora, with other minesites inbetween.

nice to know , i didnt look at WA maps for ages , many deposits in NSW also appear to be North / South . many of my maps are too big to post here but couple of pics below.

love to see maps covered in glitter...

1594131892_dubbo.jpg


1594132330_moruya..jpg


1594132394_grafton..jpg
 
CreviceSucker said:
most gold bearing reefs run north - east or within 18 degrees of it.

however plate movement could have twisted one around to be west-east

it could be a rock wall built by a welsh farmer ?
CreviceSucker - that is true for a lot of Australia but certainly not all - many are dominantly east-west in some areas. It cannpt be used as evidence if you ndo njot know the area.
I'm assuming the question is, is it a quartz vein?
"Reef" is a mining term not a geological term - many miners call quartz veins reefs. The old miners did not even use it solely for quartz, but for any hard rock layer. So the first question is, is it quartz?
 
Nightjar said:
WA deposits are generally North/South and reefs run East/West. eg: Kalgoorlie/Menzies/Leonora, with other minesites inbetween.
Have to disagree - there is no generalisation, although what you say is true for some WA goldfields. I assume you mean that ore bodies that strike north-south can consist of east-west veins, which is certainly so for some.

There is a lot to be said for using geological terminology, because the terminology of miners/prospectors varies from place to place, so they don't all agree for that reason. They tend to know their local experience. Nowadays mines use geological terminology because it is designed to be unambiguous.

Terms like "reefs" need to be abandoned, because to one person it might be an east-west quartz vein, to another an ore body (or deposit is fine) that strikes north-south but consists of east-west quartz veins (what I suspect you mean, which is true in some but not all areas). The problem is that another miner will say it is a north-south reef. To the old miners a reef was simply a hard layer of rock - they also used the term for quartzite, hard sandstone, hard dykes, as well as quartz veins. To alluvial miners in some areas, reef was simply the bedrock under the gravel.
 
CreviceSucker said:
Nightjar said:
WA deposits are generally North/South and reefs run East/West. eg: Kalgoorlie/Menzies/Leonora, with other minesites inbetween.

Should we differentiate between locations of reefs and earth fault lines ?

What is the rule for categorising the difference between them ?
Reefs are layers of hard rock (although many prospectors confusingly use the term synonymously with quartz vein - reef is better abandoned as a term as it is not a scientific term). Faults are fractures in rock along which the opposite sides of the fractures have moved relative to each other (up, down, horizontally or somewhere in between). Joints are fractures along which the opposite sides show no significant movement relative to each other. Quartz veins are layers of quartz and they usually occupy faults or joints (fluids have pumped through these fractures and deposited quartz from hot, watery solutions - it does not squeeze in like toothpaste as some prospectora think).
 
Big quartz blows are dotted all over the eastern goldfields - and only rarely are they carrying. The ones that did have been mined mostly. In fact, as a geologist who did gold exploration in the goldfields for years, I'd say they can be heartbreaking distractions. That said, sometimes gold deposits are lurking nearby and these are like red-herrings to the gold bearing rocks that are usually less obvious. Gold bearing quartz often looks different too - much clearer, maybe smokey to blue, especially if fresh. The milky-white stuff usually dissapoints (not always).
As for structural east-west versus north-south trends, this really only applies at large scale. For instance, the deposits at Agnew are controlled mostly by a series of north-south faults that intersect with changes in rock type. The trends are north-south oriented, but the individual deposits can be at all sorts of angles - the Vivien gold mine for instance was originally an outcropping quartz blow at a north-easterly angle... so when you're on the ground and come across something that looks nice, just test it! Gold finds gold as they say. If going off maps and air photos, you need to put together the geological argument really...
 

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