Geo 365: Feb. 18, Day 49: Abert Rim

Looking north from a pull-out along US Route 395, Abert Rim to the right, Abert Lake to the left. Abert Rim is frequently described as "the most prominent fault scarp in the US," but I'm always dubious of claims of extremity. Just in Oregon, Steens Mountain is higher and longer. The rise of the Sierras over Owens Valley- a few hundred miles south along this same route- is four times the height of Abert Rim, and far longer. So I'm not sure where that claim came from, and I don't think it merits consideration.

Still, it's a marvellously sharp, steep escarpment, a classic of basin and range. I'm not positive, but I think the basalt it's made of is from the Steens Basalt eruptions, now classified as part of the Miocene Columbia River flood basalt eruptions. Lake Abert is a saline remnant of pluvial Lake Chewaucan, and an important stop for migrating birds. Brine shrimp thrive in its water, and are a food source for the birds. There is also an operation that harvests the shrimp for fish food and other uses.

Since it looks like the rain is supposed to come back in earnest this week, I decided to go with hot, sunny photos for this next set. Photo unmodified. August 20, 2011. FlashEarth location, cross hairs on the spot with the pull out, I think. There are some interpretive signs there that are good for those with little background- nicely done, but not terribly useful for someone already familiar with the geology of the region.