Ordinary granite is a tough rock—the toughest on planet Earth—but it still cracks easily, exposing it to the wrath of erosion.

But the granite that makes up the Yosemite landscape is different. The area had been subject to repeated volcanic activity again and again over millions of years, causing the Yosemite granite to cool down at a slower pace, allowing the crystals to grow big and robust, rendering the rock near-immune to erosion.

If the granite of the entire world is that tough, would it have any noticeable differences in landscape and the culture of mining?

  • $\begingroup$ I think the "half" in "half dome" makes a point about your thesis that it's immune from erosion. $\endgroup$ – JDługosz Jan 17 '16 at 10:27
  • $\begingroup$ I said NEAR-immune. $\endgroup$ – JohnWDailey Jan 17 '16 at 14:39
  • $\begingroup$ @JDługosz It took a glacier to make it half, and since then it is pretty much intact. $\endgroup$ – user58697 Jan 17 '16 at 19:29
  • $\begingroup$ Mountains lose a mm of height each year from normal weathering, as a typical average. So in 50000 years you would expect 50 meters of loss. Perhaps slower loss due to climate or harder rocks would only be 10m, which would not change the shape of the features but is still significant (and normal) on a geologic time scale. $\endgroup$ – JDługosz Jan 17 '16 at 22:18
  • $\begingroup$ Flowing water is also significant in the formation of geologic features in Yosemite. So I woukd not say it's immune. Also it appears that there are a range of hardness of granite in the region. $\endgroup$ – JDługosz Jan 17 '16 at 22:25

It matters what we are mining. The class that would be most affected are called Granite related hydrothermal ores like skarns, Porphyry copper deposits, Hydromagmatic magnetite and Intrusive-related copper-gold deposits.

The economic answer would be that Copper, Iron, Uranium, Lead, Molybdenum, tin, Tungsten and Gold would be more expensive and that our expertise in mining in hard granite better than it is now.

There is a lot of metal in non-granite ores. If granite was a too hard nut to crack we would use them up first.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.