Significance of Plutons, Question regarding Plutons Options

[Shawnee Man]

I read the thread on the significance of faults. It brought to mind another geology question. I have been doing some reading on the Pikes Peak Batholith and found that the formations of Plutons in this area seem to have a correlation with mineral formation. Can someone expand on this for me please?

[EMac]

I imagine a geologist could wax poetic about this, but my understanding is a lot of the minerals were injected into the veins and fractures around plutons via a hydraulic process (minerals are dissolved into a solution, heated and the gases/liquids condense in the veins).

This may help (excerpt taken from page 45 Epithermal Gold Deposits Part II):

A process of mixing of magmatic solutions with a peripheral convective meteoric water system in the vicinity of a differentiating pluton is consistent with the timing, zoning, and characteristics of the numerous deposit types near the Porphyry Mountain stock. Gold deposits elsewhere in the district may have had a similar origin, although a relationship between intrusive events and vein deposition elsewhere is less clear.

[EMac]

Assuming this guy is who he says he is, it gives a little background on the Cripple Creek district. Taken from here:

After Carlin and Homestake, Cripple Creek is the third most productive gold district in the US. The ores from Cripple Creek have an origin different from other gold deposits in the Front Range. The gold at Cripple Creek was formed within or at the margin of a Tertiary volcanic breccia. These rocks occupy a steep-walled volcanic caldera about 4 miles long and 2 miles wide that was a result of gaseous eruptions. Explosive fracturing and subsidence produced shear zones in the breccia and adjacent Precambrian rocks. Along these shear zones, various dikes and irregular masses of volcanic rocks were emplaced, including latite, syenite, phonolite and lamprophyre. These dikes were more porous to fluids than the surrounding Precambrian granitic rocks, and in many places became the conduits for the ore bearing brines.

These ore deposits are epithermal and found along persistent veins. Many of these veins lie close to the margin of the breccia mass while others persist into the breccia or extend into the adjacent Precambrian rocks. The veins are narrow, high-grade zones mineralized with gold, silver and copper tellurides, pyrite, sphalerite, galena and tetrahedrite.

The gangue minerals (associated minerals with no value) are chiefly quartz and fluorspar, with dolomite, ankerite and celestite.

The most spectacular discovery at Cripple Creek was the Cresson Vug. This cavity, roughly 25 feet by 12 feet by 40 feet high, was found in 1914, and was lined with gold tellurides, quartz, celestite and clay. Nearly 20,000 ounces of gold had been mined from this vug.

[swizz]

"This cavity, roughly 25 feet by 12 feet by 40 feet high, was found in 1914, and was lined with gold tellurides, quartz, celestite and clay. Nearly 20,000 ounces of gold had been mined from this vug."

I just fell out of my chair.

[EMac]

The Cresson mine is pretty impressive:

Gaussling Wordpress Page 1
Gaussling Wordpress Page 2

[Shawnee Man]

Assuming this guy is who he says he is, it gives a little background on the Cripple Creek district. Taken from here:

Thank you Emac. That certainly addressed my request. I find the formation of intrusions fascinating.

[yakyakgoose]

Thank you Emac. That certainly addressed my request. I find the formation of intrusions fascinating.

I like this stuff also, I like to know all the how and why behind all these minerals etc. Hopefully makes me a better rockhound than just going to the locations everyone knows about.