Any Geology Experts?

[Suz]

Has anyone ever heard that a vein of quartz leads to gold?

Is there any truth to this?

[sbkelley]

Indeed they can. Hard-rock miners used to look for quartz veins in schist, especially back around the gold rush. If I understood chemistry better, I could give you a really techy answer, but I'll give you this:

http://www.britannica.com/EBchecked/topic-art/624717/118762/Gold-bearing-quartz-veins-Blue-Ribbon-Mine-Alaska

From a mine in Alaska.
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Mountains complement desert as desert complements city, as wilderness complements and completes civilization. - Ed Abbey

[PageRob]

'Tis true!
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Anywhere is within walking distance if you spend the time.

[kurthzone]

I come from a family of Arizona miners and as I recall being told at a young age, where there is a LARGE quartz vein there also lies gold, silver and other metals.

Check out these veins:


http://www.soltoro.com/rayo.htm

http://econgeol.geoscienceworld.org/cgi/content/abstract/97/2/269

http://biz.yahoo.com/iw/090212/0473559.html

This geology lesson may answer your question as well:

http://www.northernminer.com/Tools/Geology101/geo101.asp
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[Suz]

So tell me what LARGE is......how about 50 or 100 feet long and 10 inches wide...is that large?
Largest one I've ever seen........

[kurthzone]

[kurthzone]

Let me guess Suz, you've found the Lost Dutchman's Gold Vein!
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[Suz]

I did read a bit, but not all....but I will!

If it's the Lost Dutchman's Gold Vein, it's slightly misplaced.........which I suppose could happen especially considering how different the two GPS units were performing.

[kurthzone]

It's kind of boring reading unless you're into that sort of thing. Suffice it to say some of the veins are ginormous. The Geology 101 is pretty good. Here's a sample:

July 28, 1997
Quartz-Carbonate vein gold deposits, Part 1
by DEREK WILTON

Quartz-Carbonate vein gold deposits (also known as mesothermal lode deposits) form along, and are localized to, major regional fault and fracture systems, but are actually located in secondary or tertiary structures. These vein deposits form from hydrothermal (hot aqueous) fluids, which were derived deep in the earth's crust at a medium geological temperature (250 to 400C).

The fluids use the fault/fracture zones as permeable channels along which to flow from their region of origin until they reach a point wherein any of a number of factors -- chemical reactions with country rock and/or changes in the temperature and/or pressure -- causes the fluids to precipitate. The gold precipitates out of solution along with the quartz vein material. These regional fault systems develop during the waning stages of continental collision and hence can form at significantly later periods than the host rocks; as such, they are termed "epigenetic."

The actual host rocks of the quartz-Carbonate veins are affected by these fault/fracture origins and can range from mylonites to fault gouge. Mylonites indicate deformation under confining pressures sufficiently high that the rock recrystallizes to a fine grain size. This is plastic or ductile behavior, and indicates that the vein formed deep in the earth's crust. Alternatively, if the fault/fracture cuts a rock at a level close to the earth's surface, then it does not have the same confining pressure and hence will break into fault gouge.

Typical quartz-Carbonate vein gold deposits consist of quartz veins with gold, pyrite and/or arsenopyrite. The gold is usually pure gold and can be present in textures ranging from solitary grains to grains intimately intergrown with sulphide minerals. In some deposits, gold is present as "invisible" intergrowths with sulphide minerals such as arsenopyrite (that is, the gold is in the crystal lattice of the sulphide mineral). In other deposits, the gold is not pure but electrum -- a mineral made up of gold, with 20% to 80% silver.

Quartz-Carbonate vein gold systems are characterized by abundant, typically iron-rich, hydrothermal carbonate alteration assemblages which spread into the host rock from the vein. They represent pulses of fluid which flowed along the fracture/fault plane into the surrounding country rock with which they are not in chemical equilibrium, producing chemical reactions and the resultant alteration halo.

Alteration associated with gold mineralization also involves sulphidation (sulphide halos are a characteristic alteration phenomenon of most quartz-Carbonate vein gold deposits) and potassium metasomatism (potassium is usually enriched in the alteration halo around the veins). These halos overprint pre-existing alteration assemblages in the host rock. Any rock type can host these vein systems, but, at best, they are developed in mafic rocks such as basalts, greenstones, gabbros and turbiditic shaley sedimentary rocks; this is attributable to the chemical contrasts between host rock and ore fluids. The ore fluids are silica-rich with carbon dioxide and potassium; hence they react best with mafic rocks, which do not contain free silica but which have calcium-iron-Magnesium silicates that can react with carbon dioxide to form carbonate alteration minerals.

Gold abundances are characteristically low in most geological materials. The average crustal abundance of gold is on the order of 3 parts per billion, and generally no single rock type is preferentially enriched in gold. As a result of the low background contents of gold, a large amount of rock must be affected by the hydrothermal fluids in order for sufficient deposits of dissolved gold to be formed. The general model for these deposits suggests that the associated regional faults have deep roots that extend down to the lower crust. Hydrothermal fluids, which contain gold dissolved from a wide region, are formed, and these are focused up along the faults to higher levels in the crust, where they react with country rock to form lode gold ores.

The author is a geology professor at Memorial University in St. John's, Nfld..


August 4, 1997
Quartz-Carbonate vein gold deposits, Part 2
by DEREK WILTON

In temporal terms, quartz-Carbonate vein gold deposits apparently have been restricted to specific intervals in the Earth's history, including the Late Archean, Early Proterozoic, early Paleozoic and Early Mesozoic periods. They are best developed in Archean greenstone belts within Archean cratonic areas, such as in northern regions of Ontario and Quebec, Western Australia and southern Africa.

In Canada, the best-known Archean-related mines include the Giant in the Northwest Territories and, in Ontario, the Campbell, Red Lake, Dome, Hollinger and McIntyre, as well as the Kirkland Lake camp. Examples of Proterozoic-related gold-producing regions include Saskatchewan's Star Lake and La Ronge districts. Examples of Paleozoic-Aged formations include the Meguma deposits of Nova Scotia and the Baie Vert occurrences of Newfoundland. Mesozoic-related operations include those in the Bralorne and Caribou districts of British Columbia.

These quartz-Carbonate vein deposits are Canada's primary gold producers and are one of the most important producers worldwide. In general, a minable deposit of this type contains a grade of 6 to 10 grams gold per tonne within 2 to 10 million tonnes of ore.

The drilling and assaying of this sort of deposit can be complicated and fraught with difficulty. The veins themselves usually can be readily mapped through drilling, but determination of the true gold content can be difficult as a result of the so-Called "nugget effect," in which all the gold within an interval can be concentrated in a single point.

The assaying of vein material that is small in quantity but which contains a nugget can yield an erroneously large grade for the system, whereas if a gold-rich nugget within the vein is missed, erroneously low grades can result. To test a deposit properly, sampling must be thorough and completed on a statistically rigorous basis.

Since these veins have rather limited areal extents, the most economically favorable are those with a larger alteration halo. Those halos can also be auriferous, with economically exploitable gold concentrations. Exploration for quartz-Carbonate vein deposits can generally be restricted to orogenic (mountain) or greenstone belts, and the large-scale planar fault-fracture structures therein. Mapping of fault systems and alteration is essential.

Because of its low concentrations in the natural environment, gold is often difficult to detect; hence routine procedures for geochemical exploration (lake sediment surveys, for example) are often too equivocal for tracing the metal in the geological environment. Some elements, particularly antimony and arsenic, are so closely associated with gold that they can be exploration targets in the search for gold since they are much easier to detect. Such elements are known as pathfinder elements.

The best geophysical exploration techniques to use in the search for these types of ore deposits are those that map out fault structures. Techniques employing electromagnetic and magnetic technology would be of little assistance, as the amount of metallic minerals in the veins is usually limited.

These vein systems are planar objects with a much greater length and depth than width, and they are hosted in solid rock. As a result, they are not usually amenable to open-pit mining operations but, rather, are exploited via underground methods.

-- The author is a professor of geology at Memorial University in St. John's, Nfld.
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[Suz]

I'm confident this area fits the geological expectations for a fine chunk of something special.

So I've been researching how to stake a claim. This is what I've found.

Federal Lands Open to Mining
There are federally administered lands in 19 States where you may locate a These States are Alaska, Arizona, Arkansas, California, Colorado, Florida, Idaho, Louisiana, Mississippi, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, and Wyoming.

Mining claims may not be located on lands that have been
(1) designated by Congress as part of the National Wilderness Preservation System
(2) designated as a wild portion of a Wild and Scenic River, or
(3) withdrawn by Congress for study as a Wild and Scenic River

My Question....
because it's a wilderness area does that mean it's a part of the National Wilderness Preservation System? If so, are there ever any exceptions?

[PageRob]

You did find the Dutchman's mine, didn't you?!
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Anywhere is within walking distance if you spend the time.

[Nighthiker]

Not all wilderness areas are the same, since inception some are exempt from certain rules. Areas outside of wilderness areas can be withdrawn from mineral entry. Quartz may lead to gold but not always. Certain conditions must be present during the formation of the rock strata over a period of time, kind of like not all cookies have chocolate chips certain conditions must be present.

[Suz]

So how exactly do I find out if this BLM land is part of the National Preserve Land? Do I just ask Shawn or WindyGoldMesa? or is there online information?

[Shawn]

I hate to be the big monkey wrench in your aspirations of wealth and fame.

The days of the burro, pick axe and lonely miner are long gone; gold mines cover hundreds if not thousands of acres, require billions of dollars and decades to develop. The Wilderness areas were likely quite studied formally for mineral resources prior to designation. This happened over decades of prospecting by those burro-pick axe miners, then by more sophisticated methods. This is not to say there are no undiscovered mineral plays out there (several of the largest mineral resource deposits have been discovered duing my working lifetime) but it would be unusual to say the least. The area received considerable prospecting owing to the mines in the Bradshaws. There is a mine south of the wilderness and south of highway 74, but the gold can't be amalgamated, that is, it is too fine to retrieve from the rock.

If all that cold water doesn't dampen your go-broke-slow-and-hard enthusiasm, let me tell you about my map to a famous gold mine a bit to the southeast of the quartz seam.
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The bear went over the mountain to see what he could see.

[PageRob]

Call the BLM and ask. They'd probably know best. You might also be able to find the info here:
http://sco.az.gov/website/parcels/viewer.htm
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Anywhere is within walking distance if you spend the time.