What a Trip! 2018 Edition (Part One)

I did two geology trips in 2018. The first was with a couple of non-geology friends, in mid-June, up to Quartzville. They had a great time, but I kinda feel as if I've beaten Quartzville to death, and I didn't take any photos (though I did, of course, come home with more rocks), so rather than belaboring it beyond saying we basically followed this guide, that's all I have to say about that.

On the second trip, from September 4 through 9, we hightailed across the Cascades at Willamette Pass (Route 58, from roughly Eugene to Crescent), and made a quick stop at Salt Creek Falls. That waterfall is the second tallest in Oregon, after Multnomah Falls.

I also pointed out the glacial striations on the columnar basalt near the top of the falls.

These two photos weren't from this trip, but from August 8, 2011. The memory chip in my camera was nervously close to full, and the card reader in my laptop stopped working, so I had no way to make more space on it (as far as I knew at the time). As a result, I was more miserly about photos than I might normally have been.

Our first real excursion, after coming down the east side, taking the Crescent Cutoff from Rte 58 to Crescent, then north on Rte 97 to La Pine, then southeast on Rte 31 to Fort Rock Road, and east to Christmas Valley, was at Crack in the Ground. Location here, cross hairs over the parking area.

As you can see in this shot, there's a decent path, with a lot of ups and downs over piles of breakdown. Here, I'm at the top of a "hill." looking down into a "valley" with Hollie and Gary. Crack in the Ground is a weird feature, and unique as far as I know. When I was an undergrad, it was thought that asymmetric subsidence associated with the emptying of the magma chamber that fed the Four Cones Volcanic Field had localized flexure at this location, essentially "hinging" along this line, with the east side down, and the west side remaining at its former elevation. Evidence has popped up (I don't have the source available at this moment) that there is a pre-existing fault under the younger lava flows, so that fault may have provided a weak area that helped localize the flexure more narrowly to this location. The total length of the walk, from the car to the crack, through the most popular segment, and back to the car again, is probably about a mile and a half. The crack totals about six miles long, but much of it is prohibitively rugged for me, with enormous piles of large boulders tumbled one atop the other. This segment, though it has a lot of up-and-down clambering, is pretty easy.

The crack has its own microclimate, cooler and moister than the surrounding arid scrub. I was quite started the first time I encountered stinging nettle there (and a little bit itchy and sore), but I've learned to expect and point it out to others. Also, being cooler, and largely shaded, it can hold winter snow quite a way into summer. There are stories of pre-refrigeration locals coming out here to have ice cream parties into July- a month that would make ice cream an especially welcome treat for a sweltering summer.

Looking up to a juniper on the rim.

And back out again! Looking north from the south end of the easy segment of the crack.

We walked back to the car along the west side of the crack. Looking northeast, you can see that this surface is higher than the ground over there. What you *can't* see is that there's a ~60 foot drop just past that line of sage in the foreground.

From Crack in the Ground, we drove back to Christmas Valley, then followed the Christmas Valley Highway east to Rte 395, where we turned south. Just before that road descends toward Abert Rim, there's a well-maintained gravel road, "The Hogback," that trends southeast into the Warner Valley and the foot of Hart Mountain. As we approached the tiny little town of Plush, we turned north to the BLM Sunstone area, where we spent the night, awed by the utterly perfect skies for star watching.

I've just decided to do this as a series. Given the progress today, I'm doubtful I'm going to get the whole trip written up before Interzone closes on New Year's Eve. Better to publish in dribs and drabs than to having almost nothing for 2018. It'll get finished when it gets finished, but having it incomplete will perhaps motivate me to get it done a bit sooner.

Upper McKenzie River/McKenzie Pass Guide

I promised a friend I would write up a self-guided tour of the area described in the title before this weekend, and if I'm going to get it done, it needs to be now. I don't have mileages, but I can post links that have lat/lon details embedded, and satellite imagery. Oh, and photos, of course. Oh, and links to old posts (maybe).

Before starting: Advice

• Gas up before you leave Sweet Home (probably cheapest here or out at I-5). There's no gas for most of the trip until near the end.
• Take food. There's a mom and pop burger joint at Clear Lake Resort, but it may be seasonal; I'm not certain it's open at this point.
• Take layers and a windbreaker. It'll be a lot chillier at Pass levels, and it's often quite windy, so even if you don't need it, be ready to warm up.
• I just checked: McKenzie Pass appears to still be open, which I expected, but for future reference, it's often closed at this point. It generally doesn't reopen until sometime in July.

Let's start with the Rte 34 crossing over I-5 as a beginning. Continue east through Lebanon, where 34 is rejoined by Rte 20, then on through Sweet Home. Stay on 20 until you come to McKenzie Junction. From I-5, I'm guessing this is a bit more than an hour, maybe 1:15 or thereabout. At the Junction with 126, there's a good pullout just after the turn. (Crosshairs on pullout here.) Walk back up the grade, west, along 20- there's a wide berm, and a great view of Three Fingered Jack.

Also, at this time of year, the vine maples are flaming red. Very evocative on the recent lava flow.

Speaking of lava flows, this is the first of many recent ones you'll see today. On the drive up from Sweet Home, you've been traveling through Western Cascades Volcanic rocks, which range in age from about 35 million to 5 million years old. Coming down this hill, you crossed from Western Cascades to High Cascades volcanics, which started about 5 million years ago, and continue to present. If I recall correctly, this flow is one of several from the Sand Mountain chain of cinder cones, at about 3000 years ago. More info here.

Head south on 126 to the Fish Lake parking area. Most of the year, this location is a meadow, but during late winter and spring melt and runoff, it fills with water and a native trout that resides in the creek most of the time occupies the lake. As it dries during the summer, they return to the creek. An interpretive sign describes their situation: apparently, they're reproductively isolated, and seem to be in the process of speciation- though that's my inference, and not explicitly stated on the sign.

Continue south, watching for signs to the Clear Lake Resort- it's a turn to the left, and always comes sooner than I expect.

A different lava flow than we saw at the junction blocked the McKenzie River about 3000 years ago. Most of the time, except for occasionally during peak melt-off, the lake is entirely spring fed, with no surface streams running into it. Nevertheless, the McKenzie River drains out of it, full-blown. There's a river's worth of springs under this lake! Also, you can see the trunks of trees drowned when they were inundated 3000 years ago!

Also, weird illusions... is this boat *in* the lake, or floating a few feet above it?

There are something like 18 lakes with the same name in Oregon, but to my mind, there's only one "Clear Lake." Note the drive in and out of the resort is south to north, so you passed the exit getting here, and you'll pass the entrance again once you leave. You have my permission to drive back through again. I mean, who could blame you? Continue south, and turn off (right) in a couple miles to Sahalie Falls.

According to the person who did her doctoral dissertation on the hydrology of this area, little or no water is added to the flow between here and Clear Lake, so this is a dramatic demonstration of just how much spring water flows into the lake.

Continue a few miles south to the Koosah Falls turn off, then drive in a ways to park. This is a frustratingly difficult waterfall to get a good view of, but there is a view area along the southern loop of the footpath.

You can also see the brink from a viewpoint there, but you can't really see the falls themselves. The really interesting thing is all the springs coming out of the walls in the lower gorge.

Continue south on 126 to the junction with McKenzie Highway, 242, and turn east (left). This looks like it's about 14 or 15 miles from Koosah Falls. Head east on 242 to Proxy falls, and park in the pullout on the left. There's a nice ~1 mile loop trail to Lower and upper Proxy Falls. The lower falls are quite spectacular.

The upper falls aren't as grand, but they *do* offer a nice analogy for all the weird water goings-on in this area: They originate as springs above the cliff, fall over it, and the plunge pool sinks right back into the ground. I don't think this "stream" even has a name; it's only a few hundred feet long. Incidentally, this lava flow is from Collier Cone, up near the North Sister, and at only 1600 years old, is the youngest lava flow you'll see today.

Continue the loop back to your vehicle, then continue driving east. You're heading up a glacial valley that was incised into the High Cascades during the last ice age, and the road switches back and forth to climb up the headwall of that valley's cirque. It gets... hairy. Take it slow and easy- the road's in good shape, it's just kinda scary. You can see why they don't maintain it for winter travel, though.

When you come out on top of the plateau, the road straightens out, the trees are much more sparse, and the views open up. This is from the edge of the first lava flow you encounter on the roadside after you're up on the plateau.

It may not look like anything special, but this young volcanic landscape is why there are so many springs: hundreds of inches of snow fall up here every winter. When that snow melts, all the water just runs into the ground, then re-emerges as springs along the Upper McKenzie River. The almost entirely spring-fed nature of that section is also why the water quality is so stunningly high. Continue east toward McKenzie Pass. There are several pull-outs on the right, with nice views of the Sisters.

Then comes McKenzie Pass and the Dee Wright Observatory. This spot is an Oregon Gem, but I'm always surprised how few know of it.

The lower story is enclosed, and each of the windows faces toward a particular volcano. The labels under the windows aren't easy to read in some cases. But the upper story is open, and has a compass rose point out many visible peaks. If you have time and interest the trail out onto the flow has quite a few informative signs.

This is more or less the end, but you have a couple of choices here. First, continue east to Sisters, then Head back to Corvallis over 20 and Santiam Pass- more scenic, but longer. Second, you can turn around and head back on 242 to 126, then follow 126 to Eugene/Springfield, then take I-5 back north to 34. Shorter and quicker, but less scenic. Hope this was fun! Below, geologists in their preferred habitat.