Finally we saw a sunset!
These rocks make the best and most fun playground ever!!! I want to go back already.
Best of all, I got intel on the Lake Tahoe rocks from friend and geology badass Professor Jessica Smay:
The following is my best guess based on your photos and what I know about the Sierra Nevada Mts. The boulders look like they are made of granite, which is formed when magma in a magma chamber cools to become rock. Then, if all the rock above the magma chamber erodes away, the granite is at the surface. The Sierra Nevada Mts are mostly granite rock because the volcanoes and rock above have eroded away to expose these cooled magma chambers. Some of the granite rock had cracks form (due to plate tectonic stresses), and when water seeped through the cracks, it weathered, or broke down, the minerals in the granite, allowing more water to seep in and make the cracks wider. Eventually the corners wore away completely, leaving the round insides (called "spheroidal weathering" if you want to look it up). If over time rain, wind, etc washed away the weathered minerals in the cracks, only the unweathered minerals forming the rounded centers were left. So the boulders were most likely not transported to the beach, but almost certainly formed in place, and the rock around it washed away.
Thanks, Jes! :)
* * *
Photos in today's story were taken by Dr. Ricci Sylla, an ObGyn by profession and avid, snap-happy photographer at all other times. She likes taking pictures mostly of food, but since the recent population explosion in her family, cute nieces and nephews show up much more frequently in her Picasa files. She hearts cake, ice cream, macarons, cotton candy and fancy desserts!
Sand Harbor Overlook
Incline Village, NV 89451