Saturday, December 27, 2014

Geo 730: December 27, Day 726: Dana's Ford

Dana doesn't drive a Ford, I don't think, but I'm not a car person, so I don't pay much attention to them, and really have no idea what kind of car she does drive. It has room for her, me and, often, a traveling companion. That's really all I need to know. But here, she's fording the small creek near Timberline Lodge. If it has a name, I don't know that either.

But for the last bit of outdoor geology before we head into look around the lodge proper (and yes, I'll twist myself into knots explaining how that's geology, too), let's take a look at the clasts in the creek. They tend toward large, but overall, they're poorly sorted. This suggests that the energy of the flow varies widely- which makes sense, given the climate and topography of this location. There's some rounding in the cobbles and boulders large enough to see well at this scale. This makes sense too- the larger clasts impact each other with more energy, rounding corners and edges rapidly, without much traveling distance. But overall, despite some rounding, they're pretty angular. This suggests we can't be too far from the water and sediment sources. The source snowfields of this creek are at most a few thousand feet, a kilometer, or so away. Now the point of this is not pedantry. The point is, if all you could see was the sediment in the creek- no horizon, no vegetation, no location- you could still infer much of the environmental setting, just from the nature and arrangement of the sediment itself. This is what geology is all about, and why it's so enthralling to me. We learn to notice the little clues, and think about them together in such a way as to paint a mental picture of the larger setting, which has often been long lost in the geological record. Here, though, we have the pleasure of the entire landscape available to inspect.

Photo unmodified. October 10, 2012. FlashEarth location.

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