Looking for Sulfides

[GoldReport]

Hello esteemed members of the board.

In my local area there are no commercial gold mines and never really have been. Through research, I came across an old State Geologist Report from the late 1800s. In it they mention that some gold was found alongside pyrite. At the time it was not of a high enough concentration that they were interested in it, but it has got me searching for this elusive deposit. I am located in the Northeast US where there is virtually no lode gold deposits to speak of. ( hardly any placer either )

I went out searching today to see if I could find this pyrite, I used a combination of the report I found with geologic maps to identify the units in question. The report describes the pyrite found at the contact of two distinct geologic units which only crop out in a few places that I have so far found. My first instinct is to locate places where streams have cut through this geologic contact and pan samples downstream of that. I would have done that today but underestimated how big of a drop I was facing and ran out of sunlight before I could find a good place in the stream where any material could build up. I was at the top of a series of short but steep water falls and only made it down about halfway before dusk started to set in.

The question I have for you all today: is there is a good way to locate sulfides/pyrite in the ground other than just visual examination?

The rock around here is quite mossy and full of lichen. I suppose I could take my wire brush and clean off any outcrops I suspect would be good but that seems inefficient and time consuming. While hiking today I saw samples on the ground with good iron staining (in a shale rock which doesn't seem quite normal to me) but seeing iron staining around here doesn't make me feel any better as there is considerable magnetite all over, I live within 5 miles of a handful of old workings.

Any tips?

I plan to keep searching but am not extremely confident for a couple reasons: around the time of this geologist report there were many scams of people finding gold so the information is unreliable at best, and if there was any decent gold to be found I think someone would have already done so given the lack of other gold deposits. I don't have a metal detector and it's not in the budget to buy one at the moment.

Will update as the hunt continues...
Thanks!

 

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[N-Lionberger]

Do you have the rest of that report? In your prospecting have you seen any conglomerates?

 

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[GoldReport]

Do you have the rest of that report? In your prospecting have you seen any conglomerates?

I'll send you a DM with the report but there isn't much more mention of the gold.

The conglomerate formation is quite extensive and easy to find. It forms the crest of a ridge about 30 or so miles long. The base of the formation where it contacts the shale is what I'm interested in but is often buried and where it crops out is often mossy.

 

[Assembler]

Yes, and was associated with pyrite. My main question, which I probably didn't word very well, is if there's any tricks to finding sulfides (pyrite) in outcrops when the outcrops tend to be mossy/vegetated. Im planning to head out tomorrow and will take my steel wire brush with me to help but any other ides are welcome.

The pyrite could be in any of the rock types within the conglomerate however the quartz's may be the best.
This is likely out of the question to use however you asked, How about a pressure washer for the moss?

For tomorrow the wire brush should work.

 

[N-Lionberger]

Pyrite doesn’t form in veins in conglomerate. Conglomerate is made from compacted river gravels and sand. The pyrite was originally deposited as part of a placer.

 

[Assembler]

One formation type you may want to look for is:

Sulfide reacts with iron: If iron is present, the sulfide reacts with the iron to form iron sulfide crystals, or pyrite.

Pyrite is found in many environments it is up to you to find or figure out the event or environment of the formation.

 

[N-Lionberger]

If I were in your shoes I would locate where the conglomerate meets bedrock and beat it up with a pick and sample with a pan.

 

[GoldReport]

If I were in your shoes I would locate where the conglomerate meets bedrock and beat it up with a pick and sample with a pan.

Thats probably what I will be doing. There are a couple of streams that cut through that contact zone which I plan to pan in addition.

 

[N-Lionberger]

Thats probably what I will be doing. There are a couple of streams that cut through that contact zone which I plan to pan in addition.

If you have a sluice box it will really speed up sampling.

 

[N-Lionberger]

We have a lot of conglomerates here in California often referred to as miners cement. Ancient riverbeds made high and dry by geological processes. Hydraulic mining was the main method of mining the cement but underground drift mining aka tunneling along on top of the bedrock was also practiced, especially in the early days before the infrastructure was in place for hydraulicking or in locations covered in rock such as under lava caps. This is an interesting subject you’ve brought up, the recovery of gold bearing ore from a placer source.

 

[Assembler]

Thats probably what I will be doing. There are a couple of streams that cut through that contact zone which I plan to pan in addition.

Do you have access to geology reports that cover the area contact zones?
What do the reports point out?

 

[GoldReport]

So went out today and traversed two areas where this contact zone outcrops. In short, I didn't find anything of note which isn't surprising. I panned one of the streams thats cuts through these formations in a couple of places and didn't find anything that told me there are sulfides present. Was a beautiful day out hiking though!

This first picture was taken at one shale outcrop. You can see some rusting which makes me think there could be some disseminated sulfides present. Not too sure but I did take a sample to crush + pan later.

The second picture is one hand sample I picked up. Not sure on this one either, the rusting made me pause and take it home. I have a couple others like this. At best I am hoping to find some pyrite bits in my pan after crushing. If thats the case I suppose next step would be to roast the ore. Don't want to get ahead of myself yet

 

[southfork]

So went out today and traversed two areas where this contact zone outcrops. In short, I didn't find anything of note which isn't surprising. I panned one of the streams thats cuts through these formations in a couple of places and didn't find anything that told me there are sulfides present. Was a beautiful day out hiking though!

View attachment 2179326
This first picture was taken at one shale outcrop. You can see some rusting which makes me think there could be some disseminated sulfides present. Not too sure but I did take a sample to crush + pan later.

View attachment 2179327
The second picture is one hand sample I picked up. Not sure on this one either, the rusting made me pause and take it home. I have a couple others like this. At best I am hoping to find some pyrite bits in my pan after crushing. If thats the case I suppose next step would be to roast the ore. Don't want to get ahead of myself yet

My favorite is oxidized rocks I just posted one I crushed.

 

[Assembler]

I'll send you a DM with the report but there isn't much more mention of the gold.

The conglomerate formation is quite extensive and easy to find. It forms the crest of a ridge about 30 or so miles long. The base of the formation where it contacts the shale is what I'm interested in but is often buried and where it crops out is often mossy.

Do you have some photos of the conglomerate formation that is next to bedrock?

 

[N-Lionberger]

Did you find any conglomerates?

 

[ConceptualizedNetherlandr]

Geologists who want to know what minerals the formation is actually made of do not wash rocks. They have no interest in weathered/biologically influenced surfaces.

They use something like this:

I've had mine since ~1980 along with my first German loupe.

You need to break off a piece and look at a fresh surface. Would help if you had some mineralogy classes so you could determine what you were looking at. That is how it has been done for a very long time. Like when that State Geologist from the late 1800s found what he reports.

He didn't have any electronics, nor did he worry about moss.

Modern Core drilling is this as well, only grabbing remote samples and likely using thin section microscopy to determine the mineralogy even if very fine grained. There is much that can be measured and determined with optical mineralogy.

Now, if I understand that snippet from the report, what he did was collect some of that conglomerate ( because that on shale bedrock can be a good thing ) crushed it up and processed it to determine value.

You are not looking for Massive volcanic sulfides in situ. You are looking for conglomerate which is a jumble of previously weathered material that long ago ( before man) could have been worked as placer but has now been buried and metamorphosed into the conglomerate rock unit he found. Very different than the metamorphic rock facies found indicating deposited minerals as a result of nearby tectonic actions over long time periods in MVS deposits.

Do that. Look for the Conglomerate unit.

Find the interface. Use your big azz pick axe to get some. Take it home and work on it. Let us know how it went.

This will be hard rock mining.

The gold he found had to come from somewhere, probably billion years or more ago. There could be a bunch of it somewhere around there. 'If' local laws would allow a full blown extraction the area has probably already been flown for aeromag and gravity. that data is usually held by large private corps. ( big oil corps have done this $ ) They would have drilled it if it was promising for large scale.

This makes me thirsty.

 

[N-Lionberger]

Geologists who want to know what minerals the formation is actually made of do not wash rocks. They have no interest in weathered/biologically influenced surfaces.

They use something like this:

I've had mine since ~1980 along with my first German loupe.

You need to break off a piece and look at a fresh surface. Would help if you had some mineralogy classes so you could determine what you were looking at. That is how it has been done for a very long time. Like when that State Geologist from the late 1800s found what he reports.

He didn't have any electronics, nor did he worry about moss.

Modern Core drilling is this as well, only grabbing remote samples and likely using thin section microscopy to determine the mineralogy even if very fine grained. There is much that can be measured and determined with optical mineralogy.

Now, if I understand that snippet from the report, what he did was collect some of that conglomerate ( because that on shale bedrock can be a good thing ) crushed it up and processed it to determine value.

You are not looking for Massive volcanic sulfides in situ. You are looking for conglomerate which is a jumble of previously weathered material that long ago ( before man) could have been worked as placer but has now been buried and metamorphosed into the conglomerate rock unit he found. Very different than the metamorphic rock facies found indicating deposited minerals as a result of nearby tectonic actions over long time periods in MVS deposits.

Do that. Look for the Conglomerate unit.

Find the interface. Use your big azz pick axe to get some. Take it home and work on it. Let us know how it went.

This will be hard rock mining.

The gold he found had to come from somewhere, probably billion years or more ago. There could be a bunch of it somewhere around there. 'If' local laws would allow a full blown extraction the area has probably already been flown for aeromag and gravity. that data is usually held by large private corps. ( big oil corps have done this $ ) They would have drilled it if it was promising for large scale.

This makes me thirsty.

No this isn’t hardrock, around here we call it drift mining.

 

[Assembler]

No this isn’t hardrock, around here we call it drift mining.

I get your 'Drift'..........

 

[GoldReport]

Geologists who want to know what minerals the formation is actually made of do not wash rocks. They have no interest in weathered/biologically influenced surfaces.

They use something like this:

I've had mine since ~1980 along with my first German loupe.

You need to break off a piece and look at a fresh surface. Would help if you had some mineralogy classes so you could determine what you were looking at. That is how it has been done for a very long time. Like when that State Geologist from the late 1800s found what he reports.

He didn't have any electronics, nor did he worry about moss.

Modern Core drilling is this as well, only grabbing remote samples and likely using thin section microscopy to determine the mineralogy even if very fine grained. There is much that can be measured and determined with optical mineralogy.

Now, if I understand that snippet from the report, what he did was collect some of that conglomerate ( because that on shale bedrock can be a good thing ) crushed it up and processed it to determine value.

You are not looking for Massive volcanic sulfides in situ. You are looking for conglomerate which is a jumble of previously weathered material that long ago ( before man) could have been worked as placer but has now been buried and metamorphosed into the conglomerate rock unit he found. Very different than the metamorphic rock facies found indicating deposited minerals as a result of nearby tectonic actions over long time periods in MVS deposits.

Do that. Look for the Conglomerate unit.

Find the interface. Use your big azz pick axe to get some. Take it home and work on it. Let us know how it went.

This will be hard rock mining.

The gold he found had to come from somewhere, probably billion years or more ago. There could be a bunch of it somewhere around there. 'If' local laws would allow a full blown extraction the area has probably already been flown for aeromag and gravity. that data is usually held by large private corps. ( big oil corps have done this $ ) They would have drilled it if it was promising for large scale.

This makes me thirsty.

I took several samples home and have not turned up anything of note. The conglomerate here is different than what you are envisioning most likely. It's very thick and quite hard, forms large cliffs. The base of the formation is frequently buried under many feet of talus, or soil.

From what I can tell from the limited literature, these sulfides/gold would have been deposited as a secondary deposit. That is, it was deposited in some fashion after the shale and conglomerate had already lithified. I've found some samples with quartz veining which supports my theory on a secondary deposition. Some hydrothermal type of deposit I would guess.

I've found some samples with what looks like iron staining but I suppose that could be just about anything?

My original question was if there's any tips or tricks besides what I've already described. I have one more locality to check out in a week or two. I definitely have been bringing my rock hammer with me, I might take my mini rock crushing kit in case I want to do some sampling in the field.

I agree with what you're saying that the best thing to do is just break that rock and get a fresh surface. Wire brushing didn't seem to reveal much of value.

There are aeromag and gravimetric maps for the area but I haven't found anything that indicates any serious anomalies. There is also large amounts of magnetite in the ground here which would skew those surveys. I highly doubt that there exists a large gold deposit here, I'm just hoping to find enough gold to prove it exists in the first place.

 

[BoulderTroll]

You've got yourself a fun little challenge! It's so fun to get out in nature and just hike up/down a small creek and waterfall. Even if you don't find gold, you'll find great views and good exercise. Best of luck!
Anytime I go on a similar hunt, my method is to go out with a rock hammer, a backpack, snacks (of course!), and a handful of different bags that I put the samples in, and label them with the GPS coordinates I take them. Take them home and do the crushing and panning there.

And don't mean to brag, but so far I'm at 100% success rate of finding no free gold in any sample

 

[GoldReport]

You've got yourself a fun little challenge! It's so fun to get out in nature and just hike up/down a small creek and waterfall. Even if you don't find gold, you'll find great views and good exercise. Best of luck!
Anytime I go on a similar hunt, my method is to go out with a rock hammer, a backpack, snacks (of course!), and a handful of different bags that I put the samples in, and label them with the GPS coordinates I take them. Take them home and do the crushing and panning there.

And don't mean to brag, but so far I'm at 100% success rate of finding no free gold in any sample

If you don't find any free gold what do you do? Just roast your crushed material for a couple hours? I imagine I will be in the same boat