ironstone?

[Buzz]

Need some help identifying if this is ironstone?or just hot rocks, The sdc 2300 was going off over it, so I brought home about 4 large pieces largest about 25 cm to smash up, but couldn't find any signs of gold.

Cheers Buzz

 

[Big Nugget]

looks like basalt to me.

 

[Prospector B]

Same here, it looks igneous.

 

[silver]

Did you smash a bit up enough to pan it Buzz,.. never know what it is until you see( I suppose),... does a pointer go off on individual places over the rock, or all over it , or not at all ?.

 

[Beagleboy]

I did not realized rock like that could contain gold. Quarts is where the gold is I thought. Is that wrong?

 

[user 4485]

Going off the colour & fine grain I would think it would be basalt. Detectors like its high iron & magnesium content.
Usually a dark grey to black it can also be brown > reddish brown with weathering.
If it did contain gold it would most likely be very minimal & measured in parts per million although basalt can host gold deposits. Basalt caps can also cover auriferous leads.
The Fe & Mg would be the likely cause of getting the SDC's attention.
Quartz can be an indicator of gold but not a certainty.
http://www.minelab.com/aus/treasure-talk/eight-natural-geologic-signs-pointing-toward-gold

 

[silver]

Probably like down the beach with basalt rocks, not every one of them sets off the detector(1 in 2 hundred maybe,... or less), they may set off a signal, but it doesn't usually come up as anything when the detector analyses it (ACE250).

 

[Buzz]

Cheers guys still new at the rock ID thing Yeah Silver have dolly a little up but didn't show anything will smash up the larger prices into smaller bits this arvo and have a look. Cheers mbasko for the info

 

[Metamorphic]

Do a bit of research around the general area these were found Buzz.

Basalt, although not Metamorphic, is known to aid in the precipitation of gold (Ballarat is rich with the stuff) as is its plutonic counterpart 'Gabbro', which is in large quantities throughout the Rheola region in Vic's GT.

Steady delivery of gold to a precipitation site requires a very stable watertable and as stated, these tightly grained igneous rock structures provide that stable platform and its always possible that gold formation could occur especially if the climate long ago supported Saline water tables (auriferous).

Your SDC has already discovered the other indicating factor being the rich Iron content within the Basalt.

The trick is to find the intersection of an auriferous old watertable with the present surface (natural traps), in an area where nobody has taken a metal detector yet!

Cheers

 

[Buzz]

Cheers Meta your a wealth of knowledge, the area has had a little working mainly a small creek at bottom of area thats been creviced and sluiced, also heard of an old mine within 1.5km on a run off creek within the area on private land . Most of the area is broken down quartz and I think red sandstone as in pic below

there is many of veins of this protruding the surface. A tried to pan out some more but got maybe a couple of very tiny specs.
This piece below that looks water worn had the sdc hitting higher than any other pieces.

 

[Metamorphic]

(Part 1) Well we definitively know that there has been Volcanic action in this area a long time ago because of the Basalt......this is good Buzz!

(Part 2) Iron exists within the strata as explained by the SDC either in oxide reduction or sulfide formation, or both.....this is good.

(Part 3) A couple of very tiny specs?.....this is good (check my sig)

(Part 4) Evidence of Quartz....this is good.

Dont give up on the area yet, keep looking for further indications and evidence (ie Faults/Sheers/folds etc) even though you may get nothing from the samples you brought home.

This would be my take on it.

Nothing is a guarantee, but your in with a running start.

Good luck mate

 

[Buzz]

Thanks Meta will definitely be looking at the area a bit different now and plan to have a thorough walk around before detecting aimlessly.

 

[user 4485]

Buzz - I've detected 3 basalt scattered fields & have found gold on 2 of them. The basalt can be a pain but it can definitely be worthwhile if you persist. Some areas are also definitely worse for signalling than others. The one area I didn't find gold at was a shocker - every sweep with the SDC. Still thinking about how to attack it

 

[Buzz]

Thanks mbasko , I've detected here before and nothing then in one day 6 pieces of basalt setting the SDC off kept on thinking I'm on a winner could only imagine a scattered field of it but as mentioned persistence pays off Hopefully

 

[Roscoe]

What got me scratching my head over that piece of basalt was the quartz in it. So did a bit of looking on the net and i think it might be Amygdaloidal Basalt? What do you think?

https://www.youtube.com/watch?v=RakVFbR6Sbo

 

[Barra_Mad]

Do a bit of research around the general area these were found Buzz.

Basalt, although not Metamorphic, is known to aid in the precipitation of gold (Ballarat is rich with the stuff) as is its plutonic counterpart 'Gabbro', which is in large quantities throughout the Rheola region in Vic's GT.

Steady delivery of gold to a precipitation site requires a very stable watertable and as stated, these tightly grained igneous rock structures provide that stable platform and its always possible that gold formation could occur especially if the climate long ago supported Saline water tables (auriferous).

Your SDC has already discovered the other indicating factor being the rich Iron content within the Basalt.

The trick is to find the intersection of an auriferous old watertable with the present surface (natural traps), in an area where nobody has taken a metal detector yet!

Cheers

Didn't do enough research there mate the basalt flows in Ballarat (AKA New volcanic) are only 2.5 million years old and have nothing to do with the gold that was deposited 400 million years ago.

 

[Barra_Mad]

Hey Buzz

The rock is basalt and the quartz looking pieces are melt inclusions, simple put as the magma rises from the mantel and passes through the continental crust it picks up little pieces of crust and carries it to the surface where they are deposited in the flow. So save you back mate no point crushing that piece.

Cheers