Unfortunately, my post on Mt. St. Helens isn't quite ready yet - I spent yesterday going to a lecture on geomorphology on Mars at the Northwest Geological Society in Seattle, and have a big test tomorrow to study for. (Those lectures make my month, and this one was really great. And an added perk: the school pays for our gas and the fancy buffet dinner. Swanky!)
In it's stead, here are some pictures from Jordan Craters, a small volcanic area in Eastern Oregon.
"The 27-square mile olivine basalt lava flow is estimated to be between 4000 and 9000 years old, based on the degree of lichen development on the rocks. An 18-acre flow within the field is thought to be less than 100 years old because not even lichens have begun to colonize."
It's fairly petite, as lava fields go, but really cute. (Bonus: the surrounding countryside is gorgeous.) This picture encompasses about half of the lava field. The foreground is a line of spatter cones. In the mid-ground, you can see the largest of the cinder cones - Coffee Pot Crater. The background are the lava flows themselves.
(Adapted from: Bruce R. Otto and Dana A. Hutchison, The Geology of Jordan Craters, Malheur County, Oregon, The Ore Bin, Vol. 39, No. 8, August 1977)
Coffee Pot Crater, from the rim. The detached wall block is on the right.
These are the reddest scoria I've ever seen - it really resembled raw hamburger at times. In other places, the scoria is a dark black. I hadn't seen this concentration of scoria before, but since it's a cinder cone, scoria is everywhere! It makes climbing out of the crater a bit tortuous.
This is the detached wall block, seen from the side.
The crater floor.
This is the side wall of the crater, with some stratigraphy present.
FYI: There are signs saying that all wheel drive is necessary, but if you're an awesome driver like me, the minivan'll make it.
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Unfortunately, we didn't get to explore the whole lava field, because I had to drop my mum off in Boise because her uncle died unexpectedly. After that, the stalwart minivan died in the deserts of Nevada. But that's another story.