Targets In Shale

[Machineman]

I have been working a creek and have done fairly well. There have been at least 3 spots where there seem so be a strong signal in the bedrock , which is mostly shale. I keep a rock hammer and chisel in my bag and have tried to dig some out. I feel like it's just a particularly hot spot of ground, but I dont know that it is, they seem vary localized. Any thoughts?

[UpAndDownTheHills]

So, I guess you didn't find or see any gold in the rock you dug out?  Was the fresh surface of the shale either black or gray?  If it was either of those  colors, there would be organic matter (OM) in the shale and depending on the maturity it could have been a hydrocarbon generative shale.  These kind of shales also have pyrite associated with them.  This much I know for sure since I work in the oil and gas field.  From what I've read and heard from lectures on gold deposition and precipitation, OM and pyrite can help precipitate gold from solution.  The fact that you only see it in localized areas is also a good indication that maybe it is gold because fluid flow will be controlled by high permeability zones (most likely fracture areas associated with faulting) and would be in discrete areas and not just as a blanket over the entire area.  It is also possible that the rocks are "hot" due to associated minerals from gold deposition too.

Have you tried crushing and panning any of the shale that sets off detector?

Does the gold you find in the creek look like its traveled far or sourced nearby?  If it looks sourced nearby, you might be finding the location of its source.

Either way, it is pretty exciting.

[GotAU?]

There was a creek I was crevicing in Northern California the had slate bedded with a vertical orientation running at a right angle to the current. It made the perfect riffles to catch gold but we had to pry the plates apart to get to it. Depending on the orientation of what you described, could there be individual pieces of gold mixed in with the slate?

[WesD]

If its hard slate, I would say you have pockets of magnetic pyrite in there. I have seen that in Motherload slates. Very deceiving as it sounds so good on the Minelab PI

[Redz]

Switch to fine gold or enhance and see if it ground balances out. Of course the only 100% method is to dig it out, but this should give you a good idea

[GB_Amateur]

9 hours ago, Machineman said:

Any thoughts?

From your sidebar it doesn't appear as though you have a ground balancing PI.  Got any friends you could borrow one from, or just bring them along and have them swing over it?  I have a 6 kg non-magnetic rock from the California motherload that sounds good with my IB/VLF's but is silent on my White's TDI/SPP.  (I've seen this same thing with another larger rock for the same area.)  I think it contains a considerable graphite.  An ohm-meter says it has extremely low resistance.

But even if a PI doesn't sound off, I personally wouldn't conclude there is no gold present.  Further investigation is warranted, IMO.

[geof_junk]

One trick that might help is get a large lump as possible of the rock and tune the detector to it in the air and adjust a slight negative response then test the bedrock/slate by pumping the coil up and down on the target in Manual. If it does not respond then your hopes have been reduced. Gold being devious no guarantee give on the above.😁   

[Machineman]

I do have a gpx 4500. I am going to bring better chisels and try it again. Thanks

[flakmagnet]

I was dredging years ago in a river in the motherlode. There was a lot of slate on the bottom. At one point  my partner and I chunked out about three feet of slate in broken sheets. At the bottom of that was a
4 dwt nugget. Go figure. It was not the only time, but it was the deepest. Is there clay between the sheets? That is a good indicator that gold can make its way down between the sheets.

Good luck

[GotAU?]

1 hour ago, flakmagnet said:

I was dredging years ago in a river in the motherlode. There was a lot of slate on the bottom. At one point  my partner and I chunked out about three feet of slate in broken sheets. At the bottom of that was a
4 dwt nugget. Go figure. It was not the only time, but it was the deepest. Is there clay between the sheets? That is a good indicator that gold can make its way down between the sheets.

Good luck

Good advice, it was in the clay between the slate plates where I found small bits of gold when I was up north prospecting in a Sierra foothills creek.