Sunday, January 25, 2009
Was this "bowl" on the northwest flank of Mt. Guyot formed by a local, alpine glacier in the distant past?
Several people who have read through my lengthy exploration of the glacial history of the White Mountains asked if this "bowl" (center of photo) on the west side of Mt. Guyot is a glacial cirque or a well rounded ravine. All of those who commented have actually been into the Red Rock basin and, it's true, when you stand in the bowl, by Red Rock Pond, it has the feel of a cirque and you can almost describe the line where a "schrund" might be, meaning the upper extent of snow accumulation. Andrew Riely was one of those who commented and he asked his geology professor about the possibilities. The professor told Andrew to look at soil samples showing downward movement and for signs of abraison on the rock slabs. In conversations with Richard Goldthwait I had back in the 1960s he pretty much quelled any thoughts that there might be more cirques in the White Mountains other than the 9 he identified on the Presidentials. There is a bowl on Mt. Moosilauke, he said, that could have been a cirque-in-process, like the one between Mts. Franklin and Monroe. Part of the problem, as Goldthwait defined it, is prevailing winds and snow accumulation. The wind directs snow into the cirque to add to the accumulation, there has to a lot of snow falling in the first place, cold temperatures over time to keep the snow from melting, and then a well defined snow accumulation zone to form a glacier. I have been in Red Rock basin a couple of times in the winter, in February of 1999 when there was quite a bit of snow and last winter and it does hold a good amount with current snow packs mainly because it doesn't get a lot of winter sunlight. Goldthwait had concluded that the period of local glaciation in the Whites was going on when the prevailing wind was from the west-south-west. Therefore he didn't think you could have a cirque facing due west which is pretty much the aspect of the Red Rock bowl. Anyway, I think it would be interesting this spring to spend some time in Red Rock basin and look for some of those signs Andrew pointed out.