Geo 365: May 5, Day 125: Newberry Caldera and Surroundings

I realized yesterday that this would be post number 3000 at Outside the Interzone, and I wanted to find something special for it. I didn't have to look far. Our next stop after Lava Butte, which I've been poking around for the past week in this series, and to which I'll return in a week or so, was the top of Paulina Peak, on the southeast rim of Newberry Caldera. Actually, I think it was at the park's toll booth, but I took no pictures there. Below is an annotated version with the features I can identify labeled. You'll have to enlarge to read the labels... at least I will.

From left to right, we have the South, Middle and North Sisters, a set of related Cascade stratovolcanoes that get older to the north. This edifice as a whole has been mentioned as a possible multi-peak model for Mount Mazama prior to its catastrophic eruption, and I suppose that may be part of the reason the gentle swelling of the area in the past decade was monitored so carefully. I calculated the total volume of that inflation sometime in the past year, and if it did represent magma intrusion, it was pretty trivial. Mt Jefferson, another Cascade stratovolcano, is just barely visible though the haze. As I've mentioned before, "haze" is a relative term; that peak is probably in the neighborhood of 75 miles away. But this was late summer, so not only is the haze getting worse, but there's often smoke from fires as well.

The rim of the caldera is unlabeled, but we're seeing almost the entirety of it here. Paulina Lake fills the western portion of the caldera, but unlike the more famous Crater Lake, drains via a stream that exits to the west. North Paulina Peak is the high point on the northern rim. I have always assumed that the entire caldera was filled with a single lake, but a series of aligned eruptions at the Interlake Obsidian Flow, Central Cone, an unnamed (as far as I can tell), smaller cone between Central Cone and the road, and, most recently, Big Obsidian Flow, has divided Paulina Lake from East Lake. Pine Mountain, off in the distance, is another rhyolite dome, and is likely related to Newberry. The rhyolitic volcanism here is the most recent of a westward-younging series of rhyolite eruptions; Pine Mountain is the next youngest to the east. Finally, I think China Hat is a largish cinder cone based on its morphology and symmetry. It's the small lump above and outside the rim, not the high point on the rim itself. I've mentioned the latter two features earlier in the year.

Dana is coming into town probably about midday Monday, and we're heading over to the coast to see Otter Rock that first day, leaving us four days to tour the southern Oregon coast and northern California. I have some chores I need to get done tomorrow, so I'm trying to get as much of my Sunday internetting done today as I can. I've decided to try keeping up with the Geo 365 series on the fly, so I can share at least a few highlights of what we're doing each day. August 21, 2011 is going to take roughly a week's hiatus, after which I'll return to it. Even though I'm back on my newer machine (Yay!), Blogger is still a pain with respect to uploading photos- it just stalls out for five to ten minutes at a time, but once it actually starts to load, it goes quite quickly. I'll try to post a few quick picks each day here, but I'll also be posting these so-called teaser photos on Twitter. This will be in the later evening PDT, so way past the East Coast's bedtime. So if I miss a day here, see my timeline, and rest assured, I'll catch up when I can.

Photo unmodified. August 21, 2011. FlashEarth Location