Granite fractures

Half Dome – Yosemite Musing
Here’s a weird photo. I took this on my High Sierra hike recently.

rock split ps

What you see is the power of time. Apparently years ago a seedling fell near a granite boulder. Given enough time the seeding grew and found an opening in the rock. Sierra granite is a mix of quartz, mica and feldspar. On the measure of harness scale or the MOH (clever name) scale granite lies at about a 7-8 with diamond being the hardest at 10. The mica is soft at a 2 and it is possible for the tree to have wound itself up a weak cleft and slowly push up. Perhaps rain water got in, froze and expanded. Repeat this dozens of times and the rock finally began to weaken and split as the tree grew. Then one day – boink – the rock fractured and the tree continued up. This example shows how Half Dome’s face could have been cut. Interesting.

Unrelated thought worth quoting: “Well, the rain exploded with a mighty crash as we fell into the sun, and the first one said to the second one there I hope you’re having fun. Band on the run, band on the run.” – Paul McCartney and Wings
*Mr. Half Dome – Rick Deutsch –


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