Monday, August 19, 2013

Geo 365: August 19, Day 231: The View North

(Size options; right click image for choices) This panorama is quite similar in its coverage to last Monday's, so I'm not going to bother labeling all the features; see the left half of that one for details. The main difference here is that we're a few hundred feet higher, on the balcony of the Sand Mountain watch tower, so we get a better view of a number of  landforms. In particular, Green Ridge, the east side of the High Cascades graben, is more obvious, though as was the case before, it's still mostly hidden behind Hayrick Butte. Hogg Rock, about halfway between Three Fingered Jack and Hoodoo Butte, and tucked down into the valley separating them, is also more discernible. Finally, the valley on the far left is getting into the upper reaches of the North Santiam drainage, and the peaks to the left of that are Western Cascades. I'm pretty sure this is the first time I've been able to see both sides of the High Cascades graben from one spot. This whole swath of the central Oregon Cascades has been dropped down thousands of feet, and mostly refilled with eruptive products of the modern Cascade volcanoes. As an aside, this is not descriptive of portions of the Cascades to the north or south. If I recall, there's evidence of the graben up to about the Columbia River; I'm not sure how far south it goes. But the overall structure of the arc is different in California and Washington.

Photo unmodified. August 11, 2013. FlashEarth location.

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