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chrisski

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I'm putting a picture of a Dike I'm looking at.  It's about 2 miles long with many shafts dug into it and workings along the way.  Supposedly this area has gold, copper ore, and muscovite.

I was able to walk out to it today, but access is not by my 8k truck, and I did not want to cross state trust lands carrying my prospecting equipment.

I hope to turn up some placer gold on my next visit, but could just be a hard rock area.

Dyke.jpg

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 I'd hate for a young prospector to be confused if they googled the wrong spelling.  I suppose both can be interesting:89:, in their own way.  

BRitish english's  definition/denotation   of "dyke"(( nowhere near the slang( connotation) in the pic above)) is a dam or wall built to keep out water- which is closer to your meaning( but not of geologic origin).

   To be sure, dikes are interesting. Imagining the forces involved to create them (the  forced intrusion of new material under great pressure into country rock), looking for crosscutting veins in the dike  where goodies may have concentrated/pockets created ,and hunting parallel/pocket veins to the strike of the dike( well away from it the dike itself ), all add up to an interesting and addicting obsession.   Imagine how much country rock may have eroded away to expose it( sometimes many thousands of feet above the present exposure), along with the great amount of dike material that also has eroded along with it.

     If anything, you should find some nice baublite around it as "float".

Edited by weaver hillbille
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OMG I LOL'd so hard at this thread... too funny, guys! It's okay, Crisski. You're photos made it clear what you were referring to & anyone else who took it differently let their mind wander in a "different" direction but it was pretty humorous, just the same... especially after Bill stated "Lisa is Gay" around a handful of people Friday nite at the outing when we were all quite plastered, probably because nobody in this club has ever actually seen me "with" a man of my own. Just to clear the air & in case there is any doubt, I'm not that open-minded or liberal, but I'm not one to criticize others for their chosen ways of life, either. Since I'm not a lesbian, I don't know if the content would be offensive or not, but I definitely saw the humor here.

22 hours ago, chrisski said:

I hope to turn up some placer gold on my next visit, but could just be a hard rock area.

Chrisski, regarding that intrusive dike, I wonder if that is similar to something AZMark and I came across earlier this year that intrigued us. There was a bit of old handstacking on the hillside in the area, but we didn't find any shafts. There was a long and fairly thick quartz vein running along a hillside and someone had recently drywashed and swept a small section in the wash below. The quartz appeared to have quite a bit of iron oxidization in paralell and the general geology of the area was interesting, to say the least! I'd be interested in hearing if you find any gold in the area you described.

Lisa

Edited by Oregal1976
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Au Seeker.  Thanks for editing I will fix the pic.  After the first reply, I tried to edit the title, but could not figure it out.  I sometimes read some things that are spelt the wrong way and it totally distracts from what's trying to be said, so that is what I did here.

 

The two different workings I investigated along this were small time, but much more than anyone could do in a day or two of mining. 

 

The Ore sample I took from the tailings pile outside the shaft was dark, heavy, and had some small well defined crystals on the sample.  The sample was also had some green copper like compound.  Not sure what they mined here.  I hope gold, but it could have been less valuable ores also.  The USGS sites do not name this site as it does the others.  This site had at least six shafts of unknown size.  The entrances to these shafts were the average size I've seen in the area, about six by six.  They went down at a 45 degree angle, so the rains had filled them in, so I can only guess how long they were.  With the amount of tailings, I would judge them to run a few hundred feet tops.  This size operation, I feel like a few of us working together could make shafts like this, but we'd need some heavy equipment for this. 

 

From the other end of the dike, the guy had worked it and there was some fine crushed white quartz samples.  The ore tailings were the exact opposite of the other side of the dike.  The relics at that site led me to believe that he had a tiny dump truck, like you could put on the back of an F-100, crushed the quartz into dime sized chunks, and then dumped this on the side of a hill.  Don't know if he used a jackhammer or what, but I could see myself working with minimal motorized equipment, and making the site.  I wonder what they did to the ore between the time they dug it and it ended up in the tailings.  It looks too big to be gravity extraction and I don't know enough about chemical extraction.  There was at least a little gold taken out of this site.

 

Along my hike, I noticed no place where anyone had ran a drywasher, but the creeks were too difficult to get to for this trip.

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  • 2 weeks later...

WeaverH- thanks for the information on the dikes.  I always knew they were important.  Just never knew exactly what to look for in association with these formations.

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1 hour ago, Andyy said:

WeaverH- thanks for the information on the dikes.  I always knew they were important.  Just never knew exactly what to look for in association with these formations.

 What I posted is  pretty basic- just have to let your mind  take the place of the intrusion(dike) cracking into the country rock well below the surface, eons ago,, as well as the stresses involved that  created similar , parallel features in the vicinity.  The surface topography, present day, is a charade, a mask, compared to when it  originated.  

     When you find a piece of float/"placer" baublite (or better) near such a feature, it can be helpful to note the inclination of the dike( is it overhanging one way or the other) as well as the strike, in order to understand better where there may be a better chance of finding more goodies(( in parallel to the main feature( or not)).  Maybe the float is found well away from it( or only concentrated very close).  Maybe the float is also found at depth( or just on the surface- hence the term, "float").  I  am ignoring talk/discovery  of the actual load veins  in the dike  that may be right under your nose.  That is to obvious ,and there are many others , more qualified than me to hold forth on that subject...

 From the following Preston Vickery- pocket hunting for gold link mentioned somewhere in this forum some time ago:

"...The story begins thousands, maybe millions, of years ago. First, the earth splits, forming cracks and fissures. These fissures form an intricate structure of veins that sometimes reach a hundred miles across the earth’s surface. A second movement of the earth, such as an earthquake, is required to create the right conditions for gold to form within this system of cracks. If this second movement occurs, an “intrusive” can be formed, allowing chemicals and minerals to enter the crack. Gold forms if the right chemicals and minerals are present in the right concentrations. “Gold is just a quirk in the way nature works,” says Vickery. “All it is, is a big break in the earth’s surface. These cavities are usually cracks that develop into veins. Small veins sometimes pocket-out into kidneys. These fill up with solutions and sometimes gold is formed.”

These “kidneys” or “pockets” along the cracks in the earth are what Vickery looks for when he hunts for gold. He says that it is possible to predict the location of these pockets by visualizing the structure of cracks in which gold has a chance to form, or “make,” as Vickery says. These pockets of hardrock gold do not usually contain as much gold as the main vein that the old-timers mined, but 30 or so ounces of gold is nothing to sneeze at.

These cracks in the earth’s surface, which develop into veins, usually form along parallel lines, all traveling in roughly the same direction. To find the pockets of gold, Vickery extends the boundaries of his search area away from the historical diggings. He tries to visualize the system of cracks that gave the gold places to “make.” Many small pockets of gold could have formed along this system of cracks, sometimes up to 500 or more feet away from the original outcropping. “You go in the area where gold has already been found. Then you look for the way the structure (of veins) is running,”Vickery says. “You just try to put yourself in the area where gold has a chance to’ make.’”

“Smaller veins that formed parallel to the main vein were difficult for earlier generations...(snip)"

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Weaver H--

 

Thanks for the info.

 

I headed back to the area, but was stopped halfway there with a flat, so I'm putting going back off a week.   Although this dike is accessible by my 8k LBS truck, the trails are not maintained and the bigger equipment that was there had been used 65 years ago or earlier, so the roads are not what they used to be.  This is my second time to the area, first was three years ago.  That way I went before, the road had been undercut by the wash.  The undercut was not visible from the road, but only from the wash.  Also this undercut is not visible in Google 3D or imagery.  I'm going to need to park a couple miles away and walk in, otherwise even though the truck can make it, would be a lot of work to get it out if something went wrong.

 

This little adventure gives me something to look forward to.

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Ok Weaver H., I have a dumb question ....

So it seems that both dikes and even schist are identified by the "dip" and "strike".  So if I am looking for patches nearby a dike or even on a hillside with schist that is angled, I would think this can give me a little more direction.  For example, if a dike has a strike (just for example) of north going for miles as in Chrisski's pic, and a dip 45 degrees east (into the ground),  then that tells me that the pressure was being pushed to the west  (upwards 45 degrees).  Therefore, gold bearing fluids might be more likely to follow the fractures in the dike in this direction as well.   So maybe that would be the side of the dike to pay the most attention to.  Am I all wet, here? :idunno:  Of course you still have the quartz and other factors to look at, but this has always been a question of mine ... how do I choose a side to detect, if  there is no obvious float eroding nearby. 

Edited by Andyy
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Interesting point....I'd always thought the dike went straight into the ground.  I thought it was a volcanic inclusion in the distant past that ran straight up.  I'll look next time to see which way it slants.  This dike does not run along a ridge, so I suspect it slants into the hill, but I could be wrong.  Nearly all the dikes I've seen up to this point are along bedrock, but this one runs along the surface soil, visible through it.

For the diggings by this part, I'll call it the North side has surface diggings, or prospects, located about 200 meters north of the dike, on what I'll call the west end.  The South side has tunnels that go into the dike area from the East end.

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The "dike" you are describing has a three dimensional aspect that can't be readily seen from the surface. Rarely are dikes or their related faults perpendicular to the surface. The intrusive "dike" minerals followed along a fault or a contact zone. Those are two very different circumstances and which one governed the dike formation can make a world of difference in the chemistry that helped mineral deposition. 

Dikes are rarely as simple as they appear on the surface. Dikes often form in rings or "swarms". The fault swarms of the upper Little San Domingo area is a good example of how these intrusions can affect the local geology and the prospectors chance for success.

Besides Strike and Dip you also need to consider Rake. It's easier to understand these concepts if you first get a grasp on Hanging walls and Foot walls. It appears from your description that both the hanging and footwalls have been explored. It's not uncommon for both to have different mineralization so being on one side or the other can be like night and day for the prospector.

Determining the Strike is relatively easy with a surfacing fault but dip and rake can be problematic without some digging. Luckily your dike has already been explored to some extent.

Look at what the gangue and country rock is composed of at those prospects and you will save yourself a lot of time and digging. Most prospects were not dug for gold and assuming every dig is about gold can lead you down some pretty educational but fruitless roads. For that reason I would suggest you study the regional geology and mineralization before assuming old prospects mean the possibility of gold.

To get good geologic maps of any region try the State Geologic map features at Land Matters. Check out the "HELP" button at the top of the map to get a handle on how the maps work. This isn't your typical internet mapping site and there are some powerful tools to help you research. You will save a lot of time if you use those tools.

After you zoom in to your general area of interest click on the map while in "i" (identify) mode. You will get a window with information on the geology of your area. Look for the item "National Geologic Map Database Query". There you will see an underlined link titled "Click for Map List". When you click you will get an extensive list of all the Geologic maps available for that area. Download all the maps and study them. If your dike has an associated contact or alteration zone research what combinations of minerals are associated with that type of feature.

You might be onto a great find or you might have rediscovered a low grade lead deposit. Do the research before you hike those miles and you will have a better idea of what to look for when you get there.

Edited by clay
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"I'm putting a picture of a Dike I'm looking at.  It's about 2 miles long with many shafts dug into it and workings along the way.  Supposedly this area has gold, copper ore, and muscovite.".................................................................
..................................................
 Perhaps you found some intersecting/crosscutting veins down parallel to the drainage shown in the pictures?
THe drainage being a zone of weakness( erosion) possibly following a natural joint plane in the bedrock/countryrock.
 A google earth view may bring any natural jointing/faulting  into better focus that may be crosscutting the dike.   But then you were already on that track looking for placer down in the gullies
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On 11/24/2016 at 10:56 PM, Andyy said:

Ok Weaver H., I have a dumb question ....   So maybe that would be the side of the dike to pay the most attention to.  Am I all wet, here? :idunno:  Of course you still have the quartz and other factors to look at, but this has always been a question of mine ... how do I choose a side to detect, if  there is no obvious float eroding nearby. 

 NO, I'm all wet, as I have no real world experience  with a detector, I just read a lot.  AS they say, "gold is where you find it" and, "assay, assay, assay"... XRF samples cost (me) $15 after I reduce to a powder in a mortar/pestle.    But an assay, can be done other ways-  dry panning in the field/ by sight( if' you've the background/experience to go on to recognize good ore).

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  • 1 month later...

Went back out to this dike and I found nothing. 

 

The workings at one end were gold bearing by the literature, and what was there led me to believe it was lode gold.  I went to the tailings piles and started on the outskirts, and found a lot of trash.  I then entered the tailing pile and found no trash until I went under a bush.  It then struck me someone had gotten to the tailings piles before me, that's why I was finding trash galore until I got on the pile itself and found nothing.  I can guess I missed by a year or two because the bush was not that big that hid the nails. 

 

I also had a 80X loop looking for gold throughout the claim and got nothing.  I would have loved to drywash, but the rains prevented the soil from being dry enough.  Also, the mile and a half trail to this place was too hard for my pick up and it's a little much for me to carry the Keene Pony and other digging equipment. 

 

On an up note, three's a lot of unclaimed BLM land here.  What I discovered is that people do not like to stake claims unless there's a road to it that you can drive to.  Most all the places I've been before I could take my pick up within a quarter mile, but this place I could not.  I had to hoove it in a mile or more.  Roads are real sparse in this area.  Also a map study revealed a couple of prospects that are hidden behind a hill from the trail I walked.  I missed them on Google until I compared the 1964 USGS map to Google Maps.  The trails that lead to this are mostly overgrown, and for the desert to be that way, must be old.

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The dike itself, may not have anything, but the area does.

After going to the area three times, I've come to the conclusion that the area was mined mostly for mica.  The latest GPAA magazine had an article about a Mica mine producing 100,000 pounds of Mica and it being worth $140,000 in the late 1800's or $1.40 per pound.  That mine the article was about continued on until the mid 40's.

This workings on this dike has buckets of mica lying around that can be picked up off the ground.  That's what I think most of the diggings were after.  The best documented mine along the dike did produce gold.  Whether it had anything to do with the dike or not, don't know.  It was still a small one person operation. 

There was another mine in the area consisting of several short shafts, and with a bit of help I got info from Mindat.  For those that have used mindat before, it's a tool to be taken lightly and not the single source gospel.  The shafts were supposed to be a mica mine, quartz and feldspar mine, but there is no evidence in any of the tailngs of feldspar, mica or any quartz.  There was some tailings of a black ore stained green like copper, so I think this was a low grade copper shaft.  Anyway, they stopped on those shafts after digging them 50'.  We all like to take geo cords, plug it in our GPS, and walk there, but sometimes the cords off of mindat are a mile or more off.  Whatever mine I was at, even though very close to the minedat coords, was not the one described in mindat.

This particular area is in the gold producing belt by the San Domingo wash.  No one really know where all that placer gold in the area came from.  Very, Very, few hard rock mines ever produced anything worth mentioning.  Those that did produce gold, had lode gold coming out of them nothing like the placer gold on the surface.  So, like most areas, the "mother Lode" of the area yet remains to be identified.  The best explanation I heard is the placer gold came from mountains that used to be thousands of feet above the ground, but over millions of years eroded away, and left the placer gold.  The best gold I've found is in the tertiary gravels.  Tertiary gravels are 2.5 million years old to 66 million years old.

Also, this area with the dike is nothing I hear of people going to, but there are by far more workings here than at the San Domingo itself.  Whether people aren't going there because there is no access or no gold, I'm not sure.  I didn't expect to find nuggets.  My true sampling is done by dry washing, but it's way too wet here for that.  I'll go back once more when its a bit drier.

An 1880 $1.50 adjusted for inflation is about $50 today, so if Mica was still worth that much, I would pick up buckets of it and sell it.  Unfortunately, crushed Muscovite is sold by the ton for hundreds of dollars, so the mica is worthless to me. Best I can gather that Muscovite (crushed mica) was worth mining by the small miner until the mid 40's and then it went from being sold by the pound to be sold by the ton.

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If you are out to actually find gold I suggest focusing looking for signs of chalcopyrite ore bodies, they gave the chunkiest gold and the best historical placers were never far from these lodes (which occur in NW - W dipping trends). I'm sure there's plenty of adventure around dikes, not so sure about gold.

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All the gold in LSD wash area was delivered by quartz veins with a chalcopyrite mineral assemblage giving the greatest yields of gold (veins are long erroded into the wash), especially in historic placers in AZ. So again, why you'd be looking for nuggets next to a dike that has ZERO to do with the gold mineralization of the area is just beyond my comprehension. The only possible mineralization you might find is minor contact metamorphism of the walls of the host rock, or if the magma body that produced the dike was close enough to groundwater to produce crystalline gold assuming the minerals above said groundwater had sufficient gold. Stepping over dollars to pick up dimes man.

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The data I found says 40 ounces of gold was pulled from around the Dike.  The Dike is one small part of the area I was looking at.

 

I've never seen chalcopyrite ores around the Wickenburg area.  The goldish color and crystalline structure would have gotten my eye.  The copper ores I see are greens and browns: malachite and azurite.

 

I do think you ought to come out to AZ.  I think you'd love it out here.

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