Hidden in Plain Sight

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cuzzinjack
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Hidden in Plain Sight

Post by cuzzinjack »

After reading Dr. Glover’s new book, my hunch that most of the “lost gold” is still in the ground was reinforced. How can a large quantity of gold possibly remain?

In a previous post it was shown that there are at least 4 collapse calderas in the Goldfield Mining District, each marking the extents of the magma chamber of a strata volcano:

1) Goldfield Caldera
2) Molly Marie Prospect Caldera
3) Golden Hillside Caldera
4) Government Well Caldera

The cones of these 4 volcanoes were swept away by a deep brine lake (Lake Higley) with salinity estimated to be many times that of seawater, leaving the island of the Superstition Mountains behind as a remnant of a much larger volcanic pile. The volcanic debris was washed into a large rift zone w/ lake that extended between Gilbert and Florence and far beyond, and bare basalt was exposed in all 4 of the collapse calderas.
This miner believes that there are gold-rich VMS (Volcanogenic Massive Sulphide) deposits beneath the basalt in the calderas, and especially the Molly Marie and Goldfield calderas because:

• There are abundant gossan breccias found at the apex of an anticline in the basalt in the Molly Marie Caldera.
• Extensive alteration of basalt in the Goldfield Caldera,
• A particular account of the ore found at Goldfield:

In his booklet, “Goldfield Mining District Geology and Ore Deposits”, John Wilburn describes the bonanza ore of the Old Wasp Mine, near the Mammoth Mine in Goldfield, that was mined in 1983. Yes, 1983. I spoke with Mr. Wilburn about this strike about 12 years ago. He was there. His description of the ore there is a follows: “The ore shoot was eight feet wide and 50 feet in length. On the east footwall, free gold occurred with galena, anglesite, malachite, chrysocolla, and hematite in an extremely heavy ore 12 inches wide that assayed 244 opt gold and 56 opt silver. The sulphide ore was limited in size.”

Although small and in vein form, the description is one of oxidized, very high-grade massive sulphide ore. The Old Wasp and the nearby Mormon stope are located on the edge of the Goldfield Caldera in breccias on the edge of the basalt. Can you imagine if the fluids that formed the Mormon Stope or the Old Wasp were captured BENEATH the basalt?

The gold “trap” beneath the basalt in the calderas is like none other:

1) The unbroken basalt created a barrier to stop ascending fluids and forced them to move laterally to react chemically and thermally to precipitate metals and metal sulphides.
2) Leached Iron on the altered underside of the basalt caused AuCl to precipitate as Au.
3) Quenching of hot fluids with cool Lake Higley water caused precipitation by cooling.
4) Alkaline Lake Higley water neutralized ascending acidic fluids creating precipitation.
5) Abundant limestone gravel and cobbles found immediately beneath the basalt neutralized acidic fluids and caused precipitation.

Where is the vent or neck of the Goldfield Caldera? After hiking many miles in and around the “Goldfield Caldera” it was learned that the bald, hard knobs of rock that are inside the area labeled “volcanic neck” in the Goldfield Caldera photo below are actually overlapping breccia pipes comprised of dacite breccias. The breccias are silicified, and in some can be seen spectacular drusy quartz crystals with a 20x loupe. Because the Goldfield Caldera was the most affected by Lake Higley, this volcano erupted explosively instead of by flows as occurred at the Molly Marie and Government Well calderas. Rounded breccia clasts found at the top of these pipes have been “milled” by repeated explosions.

Below is a link to the geologic model of a typical Goldfield Mining District collapse caldera:

http://mollymarieprospect.com/hiddeninp ... amodel.jpg

Here is a link diagram of a generally-related type of VMS deposit that forms beneath basalt:

http://mollymarieprospect.com/hiddeninp ... felsic.jpg

Below is a link to an annotated photo of the Goldfield Caldera:

http://mollymarieprospect.com/hiddeninp ... otated.jpg

Here is a link to a photo of chloritized basalt laced with veinlets found in the Goldfield Caldera:

http://mollymarieprospect.com/hiddeninp ... basalt.JPG

The pathfinder element that has been found to be the best indicator that brine created mineralization beneath altered basalt is Lithium. 100 to 120 ppm is common in the Molly Marie caldera in gossan breccias and chloritized basalt. Skyline Assayers of Tucson performs this test.

In conclusion, it is believed the Goldfield Mining District has been the location of the lost mines all along, and most of the stopes were beneath the basalt. Anglo attention has been concentrated on seeking veins in the breccias on the margins of the collapse calderas and elsewhere, and near Goldfield, all of the historic Anglo mines are located on the margin of the caldera. But, the basalt in the interior of the caldera appears untouched. On the margin of the Molly Marie Caldera, seismic studies have found evidence of several pits in the breccias, but it is felt that these were mined early in the history of the District. The heavily-altered basalt in the interior of this caldera also shows no sign of mine openings, but they should be there.

It is my strong belief that the extent of pre-Anglo mining in the Goldfield Mining District has been grossly under-estimated or wrongly disbelieved. Previous posts including data and photos of the physical evidence of their extensive work in the area. Accounts tell of hundreds of people(up to 800 in one account) in the pre-Anglo District at one time. That many people obviously weren’t working one small mine.

It is believed that the basalt in the collapse calderas is key, and that there is ore beneath that has barely been touched. Of special note: The basalt is only 50 feet thick.

The Goldfield Mining District, formerly known as the “Salt River District of the North” awaits the attention it has long deserved.

cuzzinjack
Joe Ribaudo
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Re: Hidden in Plain Sight

Post by Joe Ribaudo »

Jack,

That's a lot for us rock-dumb neophytes to absorb.

Nice lesson,

Joe
cuzzinjack
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Joined: Mon Jun 13, 2011 7:33 pm

Re: Hidden in Plain Sight

Post by cuzzinjack »

Hello Joe,

I tried my best, and hopefully it gets the point across about just how important this is. The more I learn, the more flabbergasted I am that the virgin Goldfield Caldera with the conditions described could exist right out in the open, and you can drive over most of it. I have nothing in the Goldfield Caldera, and the interior appears to be open ground (i.e. not staked). After looking at the Mesa BLM map, the southern half of the caldera is BLM land, and the northern half is Forest Service, both stakeable. The quarry on the northern portion of the caldera is very interesting; there are a lot of veins exposed there.

Sincerely,

cuzzinjack
Joe Ribaudo
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Re: Hidden in Plain Sight

Post by Joe Ribaudo »

Jack,

Well there is that northwest to southeast line of mineralization that runs through the Goldfield area, stops (pretty much) at the Superstition range and picks up again in the region of Globe. Believe the old silver mines in the east end of the range might be included in that line.

Not sure how many people you will reach here, but I believe it's important information to put out there.

My first real exposure to caldera's and caldrons came from reading the works of Michael F. Sheridan and a very few others. It does lend weight to what you have written, but it is out of my league.

Take care,

Joe
cuzzinjack
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Joined: Mon Jun 13, 2011 7:33 pm

Re: Hidden in Plain Sight

Post by cuzzinjack »

Joe,

I’ve read some of Michael Sheridan’s work, and he hypothesized that the reason the Goldfield ore was so rich was because the Whitetail formation contained placer gold that was dissolved and redeposited as bonanza veins. He was right, and he had not even heard of the concept of Lake Higley brine being the corrosive agent to dissolve the gold and other metals, and he did not know of the Goldfield collapse caldera existing as the heat source. If he had, I do not think we would be talking about it today, because he was an ASU professor, etc. Google Earth and photo editing software has made prospecting a whole lot easier since then.

cuzzinjack
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