We camped at Colter Bay in the Tetons. The best part of camping here was getting to wander around and look at the mountains in our free time. Our first night, we went to watch the sun set:
While there, Jordan pondered why the beach had only pebbles and no sand, which is a very good question you might ask yourself sometime. My best answer is that there is no source of sand. Beaches need a source, a river carrying sand into the region. Sand takes a while to form, being worn down from rocks that have broken out of the mountains. The mountains are very close to the lake here, which means the rocks don't get a chance to bang around in the rivers enough to turn into sand before they're deposited in the lake. The smallest they manage to get is pebble-sized.
I say that sand comes from mountain rocks because this is basically the story of geology: things get worn down from high points and deposited in low points. The earth "wants to be flat." Plate tectonics is always messing things up, thrusting up new blocks of crust, but the higher a piece of crust gets, the steeper its sides are, and the more energy the streams rushing down those sides will have. So the higher something is, the faster it gets eroded. The highest rates of erosion in the world right now are in the Himalayas. The rock is stripped from the mountains and brought down by streams into valleys and the ocean, which it fills in. The mountains are brought low and the low places are raised up. Until plate tectonics messes it up again.
The next day, it rained and rained. We went to see the Gros Ventre (pronounced "grow vont") slide, which is one of the most famous landslides in the world. According to the interpretive sign, in 1925, "some 50 million cubic yards of rock, about a mile long, 2000 feet wide and several hundred feet deep in places plunged down and formed a dam 225 feet high" on the Gros Ventre River. Two years later the dam burst and the town of Kelly, downstream, was practically wiped out.
Heavy rains are suspected to have contributed to the landslide.
We tried to find dry places to work on our final mapping project that afternoon. I huddled in the visitor center auditorium trying to focus on my work while an interesting video on one of Yellowstone's wolf packs was playing. Some other students worked in the restaurant.

The skies cleared for a while later. Here, another gratuitous sunset picture.


And another of Spasmodic Geyser, which was cute:
We saw Grand Prismatic Spring, which is famous for being on the cover of National Geographic once.

We visited Mammoth Springs too; here are some terraces formed by the hot spring water:
There are plenty of geological wonders in Yellowstone that are not hydrothermal.
Finally, we visited the falls in Yellowstone...


Well, that's it for now... we're having a party tonight, of course, not for my birthday, but for it being the last day of field camp. I will have to talk about our final fossil-collecting trip later. I also have a couple more entries sure to come, about sundry things I haven't spoken of yet, such as the wildlife of Wyoming.
1 comment:
Happy birthday! I thought about you all day yesterday.
Love,
Mom
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