The Naked Scientists

The Naked Scientists Forum

Author Topic: Chances of finding gold?  (Read 11621 times)

Offline OokieWonderslug

  • Full Member
  • ***
  • Posts: 93
    • View Profile
Chances of finding gold?
« on: 10/09/2010 05:27:39 »
I have a creek that runs in back of my house. The creek bed is an ancient rift fault that is mostly filled with basalt blocks. On the hills on either side of the creek the rocks are tan volcanic slate, then a layer of small red rocks that are highly magnetic and hard. Then a layer of red clay with large white quartz nuggets dispersed randomly. There are softball sized quartz rocks in the creek bed along with the basalt.

My guess is that when the rifting occurred there were large cracks in the cooling basalt and water flowed through these cracks slowly depositing the quartz. Would gold have been deposited too? I have looked for nuggets (not found any) but haven't yet gotten around to panning. The mosquitoes are at plague levels and I am waiting on the first frost for that.

So, does that sound like a good area for gold? I am in the "gold belt" area of North Carolina and about 20 miles from Reed's gold mine.

Any idea on the origin of the small hard red magnetic rocks?


 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Chances of finding gold?
« Reply #1 on: 11/09/2010 01:59:20 »
Mr Mining Geologist - have at it  - I am still ill.

But epithermal gold mineralization could be present.
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Chances of finding gold?
« Reply #2 on: 12/09/2010 01:12:41 »
The nearby Haile and Ridgeway gold mines were stratabound deposits hosted by volcanically associated rocks from the 500+ million year old Carolina Slate Belt island arc system.   The Slate Belt was metamorphosed when North America collided with Africa.  There are much younger granites, and even younger yet diabase dikes (possibly the basalt you are referring to) that intrude the metamorphic package.

So to your question- did the basalts cause the quartz and deposit gold?  No

Your other question "So, does that sound like a good area for gold?" is much more interesting.  The Carolina Slate belt, especially volcanic slates and phyllites, near Charlotte, is highly prospective for gold.  By all means, get down to the creek and pan for gold. 

How magnetic are these rocks??  does a magnet stick to them? Do they move a magnet?

Two magnetic minerals come to mind- magnetite and pyrrhotite.  Both can be black and both weather to a red color.  Pyrrhotite is more favorable for gold.  The Haile and Ridgeway ore zones were high in pyrite.  Or, collect some of the red rocks and send them in for a gold assay.

You just never know.  After Kinross thought they were done mining Haile, and had even reclaimed all the workings, another company came in, did some exploration, drilled a bunch of holes and discovered another 2 million ounces of gold.

If you can be more specific about the location or provide more detailed information and/or pictures, I can probably be of more assistance.
 

Offline Don_1

  • Neilep Level Member
  • ******
  • Posts: 6890
  • Thanked: 7 times
  • A stupid comment for every occasion.
    • View Profile
    • Knight Light Haulage
Chances of finding gold?
« Reply #3 on: 13/09/2010 13:26:54 »
Yes, we need a specific location.

Now where did I put that pan?
 

Offline Geezer

  • Neilep Level Member
  • ******
  • Posts: 8328
  • "Vive la résistance!"
    • View Profile
Chances of finding gold?
« Reply #4 on: 13/09/2010 18:44:54 »
Yes, we need a specific location.

Now where did I put that pan?


Pappy! Where have you been hiding?
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8659
  • Thanked: 42 times
    • View Profile
Chances of finding gold?
« Reply #5 on: 13/09/2010 19:47:36 »
"Where have you been hiding?"
In a cabin,
in a canyon,
excavating for a mine....

 

Offline peppercorn

  • Neilep Level Member
  • ******
  • Posts: 1466
    • View Profile
    • solar
Chances of finding gold?
« Reply #6 on: 14/09/2010 12:16:42 »
Pappy! Where have you been hiding?

I reckon that's just Geezer wearing a false beard!
Ya porridge looks a bit gritty though  :D
 

Offline OokieWonderslug

  • Full Member
  • ***
  • Posts: 93
    • View Profile
Chances of finding gold?
« Reply #7 on: 17/09/2010 23:30:34 »
The nearby Haile and Ridgeway gold mines were stratabound deposits hosted by volcanically associated rocks from the 500+ million year old Carolina Slate Belt island arc system.   The Slate Belt was metamorphosed when North America collided with Africa.  There are much younger granites, and even younger yet diabase dikes (possibly the basalt you are referring to) that intrude the metamorphic package.

So to your question- did the basalts cause the quartz and deposit gold?  No

Your other question "So, does that sound like a good area for gold?" is much more interesting.  The Carolina Slate belt, especially volcanic slates and phyllites, near Charlotte, is highly prospective for gold.  By all means, get down to the creek and pan for gold. 

How magnetic are these rocks??  does a magnet stick to them? Do they move a magnet?

Two magnetic minerals come to mind- magnetite and pyrrhotite.  Both can be black and both weather to a red color.  Pyrrhotite is more favorable for gold.  The Haile and Ridgeway ore zones were high in pyrite.  Or, collect some of the red rocks and send them in for a gold assay.

You just never know.  After Kinross thought they were done mining Haile, and had even reclaimed all the workings, another company came in, did some exploration, drilled a bunch of holes and discovered another 2 million ounces of gold.

If you can be more specific about the location or provide more detailed information and/or pictures, I can probably be of more assistance.


The red rocks are extremely magnetic. I ground a few of them up with a mortar and pestle and 100% of the powder was attracted to the magnet. The "basalt" is about 95% magnetic. Not all of the powder would stick to the magnet like it did with the red rocks. Same amount of powder. If you drop a magnet out in the driveway it will be coated with these rocks every time.

Also, if you heat them up with a torch they explode every time. I can't get a sample of it to heat with a torch. The black basalt will get hot and glow bright orange if you heat it.
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Chances of finding gold?
« Reply #8 on: 18/09/2010 01:59:43 »
Magnetite.  (or Maghemite)

Make sure you thoroughly dry any samples before heating.  I suspect a small amount of water is what's making them explode.

Try panning the creek for gold.  Best to try to get down to bedrock, if possible- better yet is to find any cracks or nooks in bedrock and pan that material.  If you've never panned gold before- fill the pan about 3/4 full, then submerge in water.  Work the sediment with your hands until all the mud is gone.  Shake the pan back and forth vigorously, allowing the rocks and sand to separate by density.  You can pick the larger pieces of rock from the top.  Tip the pan until the top of the sample is just below the lip of the pan- then gently dip the pan into water and let it drain over the lip, carrying a bit of the top material with it.  Repaeat the shaking, then tipping, until you only have enough material to cover half the bottom.  You will no doubt have lots of black sand.  By slowly swirling a bit of water in the bottom of the pan, you can move the lighter material which allows the gold to stay behind and visible.  First attempt will probably take you 20-30 minutes, but with a bit a practice you can reduce a pan of material in a minute of two.  Let me know what you find- even if there is no gold.
« Last Edit: 18/09/2010 02:05:03 by Bass »
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Chances of finding gold?
« Reply #9 on: 18/09/2010 02:09:32 »
Also, if the quartz is rounded, but the rock (especially basalt) is angular, then I suspect that the quartz may be amygdules (or filling the air bubbles in the basalt).  I have seen places where the amygdules have been deformed and changed from spheres to long, thin rods.  Is there any quartz in the basalt?
« Last Edit: 19/09/2010 18:13:53 by Bass »
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Chances of finding gold?
« Reply #10 on: 18/09/2010 03:27:45 »
Good Job, SON. Always knew you had promise, Bass.
 

The Naked Scientists Forum

Chances of finding gold?
« Reply #10 on: 18/09/2010 03:27:45 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums