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Geology, Palaeontology & Archaeology / Did glaciation produce this smooth, undulating rock surface?
« on: 09/09/2018 19:51:03 »
This is clearly glacier polished granite, (see attachment), but it has a small scale softly contoured formation implying plasticity post polishing which I haven't seen before. Is this a normal process that someone could explain to a layman? I.e. can polished granite later melt like this somehow, or is there some way I am not comprehending that a massive glacier could polish such a small scale convoluted surface as opposed to the typical larger / flatter surface? To put it another way... I commonly see flat, very large gently curved, or very large domes of polished granite, but never polished granite in such small / tightly rounded forms. Obviously there is a great deal of post polish splitting / fracturing / exfoliation as well, which of course is typical / expected.
GlacierPolishedGraniteSoft01.jpg (115.69 kB . 1251x600 - viewed 6638 times)
The boulder in the photo center left is approx 2' diameter. Location is at about 12,000' elevation near Mt Whitney in the Sierra Nevada Mountains of California, USA.
Thanks much for any knowledgeable feedback.
Bruce
GlacierPolishedGraniteSoft01.jpg (115.69 kB . 1251x600 - viewed 6638 times)
The boulder in the photo center left is approx 2' diameter. Location is at about 12,000' elevation near Mt Whitney in the Sierra Nevada Mountains of California, USA.
Thanks much for any knowledgeable feedback.
Bruce