Prospecting geological clues, tips tricks, signs and anything else.

[MrGneissGuy]

Hey guys I've been wanting to start a thread where beginners like me can learn from experts like you. My hope is to have a thread where everyone can openly discuss things they look for when prospecting for gold. For example, someone might add (look for red coloring - this indicates oxidation) and any explanation about why it's important for finding gold. Other examples would be certain types of rocks and minerals, colors, shapes, faults and anything like that that you look for when prospecting. It would also be nice if you would include details of your location, obviously nothing too specific. I just mean "Northern California" or whatever you feel like including for reference.

What would be the perfect combination of geological signs indicating nearby presence of gold, besides finding gold...? Would it be granite, quartz, and red stuff nearby or what?

 

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[goldenmojo]

Look at places that everyone walks right by. I have a spot that is directly under a bridge. I looked at the spot for about a year thinking it had already been worked. I finally went and sampled it and there was plenty of color, heavies and 1/2 gram pickers. I took various friends to the spot and after about a year and a half we finally worked it out. Pulled at least 50 square nails out of the pockets. Gold is where you find it.

 

[Johnnybravo300]

Look for me digging there if it's Colorado hehe.

 

[MrGneissGuy]

Look at places that everyone walks right by. I have a spot that is directly under a bridge. I looked at the spot for about a year thinking it had already been worked. I finally went and sampled it and there was plenty of color, heavies and 1/2 gram pickers. I took various friends to the spot and after about a year and a half we finally worked it out. Pulled at least 50 square nails out of the pockets. Gold is where you find it.

In Northern California maybe!

 

[bcfromfl]

Important to note that geological features relevant to the occurrence of gold are regional in nature. You don't specify, but it sounds like your interest lies in placer gold. Nevada, Arizona, and southern California are dominated by caliche deposits, the Sierras and northern California (two different geological zones) tend towards bench deposits from serpentine and volcanic zones, etc. If you look up the Blue Lead and jade, that might give you some interesting reading. Further north into Alberta and British Columbia, deposits are more common near shale and clay/saprolite.

What you propose is such a broad topic, that perhaps if you narrow it down a bit it could become more helpful to you.

 

[KevinInColorado]

Pick the '3rd best spot' on a popular creek or river. Often the 1st and 2nd are already beat hard.

 

[huntsman53]

If you are in a Gold producing area and dig down and find whitish/grey clay with red (Iron) staining and/or greyish to bluish (likely indicates Silver) clay with the same, this is a great sign for Gold. These alluvial deposits can lead to an ancient stream bed loaded with cobbles and Gold. Understand that many folks give up when digging out and panning clay as it is hard to work and most of the Gold sits on top down to the first few inches into the clay layer. However, once you have dug through the clay layer, you will likely start seeing color again 6 inches to a foot or more below the clay and may even hit more layers of clay containing Gold below the top layer. While prospecting in a North Carolina stream some 8 years ago, I dug through three clay layers mostly of different colors and began getting some pickers about 8 inches below the last clay layer. I am sure I was getting close to an ancient stream bed and bedrock as some smaller cobbles were coming up with each shovel I brought up. Sadly, I have not been able to get back there and verify that I almost dug down to an ancient stream bed.


Frank

 

[utah mason]

Pick the '3rd best spot' on a popular creek or river. Often the 1st and 2nd are already beat hard.

Really good advice Kevin. Some of my better spots I've found were on slight bends just down from a hard bend where I'm sure many people have targeted first. Plus a lot of people I've seen use a standard sluice with carpet and riffles and wash the gold down to the next spot.

 

[winners58]

sample sample sample for me it always takes a lot of work,
then I take a newbe out prospecting like my brother or roommate
I'll be damned if they find good gold and I get skunked every time...
On my claim I dredge all the likely spots when I find the gold line
I stay on that line.

something that may help, where the gold comes from;
USGS Professional Paper 73
The Tertiary Gravels of the Sierra Nevada of California
Waldemar Lindgren 1911
.
https://pubs.er.usgs.gov/publication/pp73

 

[bcfromfl]

You may find this video helpful, as I think it's similar to the spot you've been spending some time, described in another one of your threads. The one criticism I have is that the term, "contact zone," is mentioned several times, however, this term is usually reserved for describing hard rock deposits. (Liquified minerals under pressure tend to run along the barriers created by older rocks that have solidified, and this is where you'll usually see the term used.) Used here, they are describing the different layers in a bench deposit, and how the best gold is found in an orange layer just above decomposing bedrock. This location is in northern California, and may not represent how placer gold occurs in other regions:

 

[bcfromfl]

This video is from the same area as above, but demonstrates a different way placer gold can be concentrated in a deposit. Above, it's in a general cemented gravel with river-worn rounded cobbles, but below, it's in-between slanted seams of bedrock:

 

[Bejay]

Intrusive formed igneous rocks.

Bejays

 

[MrGneissGuy]

Important to note that geological features relevant to the occurrence of gold are regional in nature. You don't specify, but it sounds like your interest lies in placer gold. Nevada, Arizona, and southern California are dominated by caliche deposits, the Sierras and northern California (two different geological zones) tend towards bench deposits from serpentine and volcanic zones, etc. If you look up the Blue Lead and jade, that might give you some interesting reading. Further north into Alberta and British Columbia, deposits are more common near shale and clay/saprolite.

What you propose is such a broad topic, that perhaps if you narrow it down a bit it could become more helpful to you.

I only search for bench deposits because I haven't found gold anywhere else. I would be interested in any hard rock mining as well, and even other minerals besides gold. I just like prospecting I guess but feel like I don't know what I'm doing. There are some guys who walk around and know exactly when they find something interesting. For example there's this geologist guy on the show "Ice Cold Gold" on Discovery and he gets super excited when he sees certain things. I walk around literally looking for cobblestones that look like they were from an old river.

 

[MrGneissGuy]

Pick the '3rd best spot' on a popular creek or river. Often the 1st and 2nd are already beat hard.

Seems like around here it's the 400th spot.

 

[MrGneissGuy]

You may find this video helpful, as I think it's similar to the spot you've been spending some time, described in another one of your threads. The one criticism I have is that the term, "contact zone," is mentioned several times, however, this term is usually reserved for describing hard rock deposits. (Liquified minerals under pressure tend to run along the barriers created by older rocks that have solidified, and this is where you'll usually see the term used.) Used here, they are describing the different layers in a bench deposit, and how the best gold is found in an orange layer just above decomposing bedrock. This location is in northern California, and may not represent how placer gold occurs in other regions:

I'll check it out this seems amazing, thanks!

 

[bcfromfl]

For example there's this geologist guy on the show "Ice Cold Gold" on Discovery and he gets super excited when he sees certain things. I walk around literally looking for cobblestones that look like they were from an old river.

I tried watching this show, and the bios of the team looked impressive. But after I saw all the bone-headed shenanigans and giant egos, and them getting excited about low-grade rubies that were hardly worth chiseling out of the rock, or trace amounts of gold...again...not worth mining -- yet everyone hooting and slapping high-fives, I gave up.

If you can ignore his silliness, watch some of Jeff Williams' videos ("Ask Jeff Williams") on YouTube. He is as knowledgeable as any PhD in geology, and in some of his videos describes how and where gold forms, and the types of rock to look for.

 

[winners58]

a couple of good video series to learn what to look for

from Tom & Josh Bohmker;
https://www.youtube.com/channel/UCKlNL5LmeWdLcRhzkXDdtbA

and a good series from Matt Mattson;
https://www.youtube.com/channel/UCPSsiJFU2JVh-dfIn1jfZDg

 

[Bejay]

So lets see if some nubies know why you would look for Intrusive Igneous Rocks? (One must acknowledge these can be found in placer and hard rock locations)...but why is this so important. Now let us let the nubies answer this one!

Bejay

 

[MrGneissGuy]

So lets see if some nubies know why you would look for Intrusive Igneous Rocks? (One must acknowledge these can be found in placer and hard rock locations)...but why is this so important. Now let us let the nubies answer this one!

Bejay

I was literally thinking about this over the last 24 hours....too embarrassed to ask. I'll take a stab at it though.

Examples of these rocks would be like granite and gabbro. My guess would be that during high pressure and temperature events such as earthquakes, these rocks are probably "pushed" up from wherever they were, and gold might be a mineral byproduct that would be pushed up with it or something?

 

[Bejay]

On a scale of 1 to 10 for an answer....10 being you really got it right I would score you a 3. you only gave 2 examples of intrusive igneous rocks and you said byproduct. But you are on the right track. Remember one thing: both placer and hard rock mining can utilize this knowledge and it is the most significant tool associated with locating valuable locatable minerals. I can't say more without giving away the significance.

This is a "geology 101" aspect of Geology/Mining. Thanks for giving it a lot of thought. Think some more....I believe you may come up with a better and complete answer. Having a Geology background and having been a miner for 40 years I can attest to the importance of the "Intrusive Igneous Rock" awareness. Maybe the geologic term "Orogeny" might help you get there.

Bejay