Shallow Thoughts

Rainbow Basin: the Barstow Syncline

We started the day at Zzyzx, south of Baker. I'd been told that there were lots of geologically interesting things to see there.

If so, we couldn't find them. There's a little cluster of buildings marking the Desert Research Center, but it doesn't seem to be open to casual visitors; rather, they do classes and tours by appointment. Zzyzx abuts the southwest end of Soda Dry Lake, so you can get good views of the dry lakebed (with a little water on it here and there, thanks to the very wet winter) and across it to Mojave Rd and the Kelso Dunes. Worth the 5 mile detour off the freeway? Well, no, not really. But Dave was happy to find a relatively windless place where we could fly model airplanes for a few minutes.

Fortunately, Zzyxz wasn't the target of the day; that honor fell to Rainbow Basin, a few miles north of Barstow on the road to Fort Irwin. We'd actually tried to go to Rainbow Basin once before while passing through Barstow, but got lost. This time we had a more detailed map, since Rainbow Basin occupies a whole chapter in Geology Underfoot, Southern California.

Except it turned out that map wasn't any better than the wide-scale auto club map. The problem is that when you're coming in from the northeast, there's an exit off I-15 for "Fort Irwin Rd", even though no such exit shows on any of the maps. Fort Irwin Rd. is the road all the maps show as leading to Rainbow Basin. So that's the road to take, right?

Well, it turns out that Fort Irwin Rd and the more westward Irwin Rd angle together to meet at a point well north of the Rainbow Basin turnoff, which is on Irwin Rd. Irwin Rd. is the road all the maps label as Fort Irwin Rd, while Fort Irwin Rd. doesn't exist on the maps at all. Confused yet?

Here's the secret: if you exit I-15 at Fort Irwin Rd, make a left when you get to Irwin Rd. and angle back toward Barstow. Drive for longer than you think you should, and Look for a dirt road going off to the right called Fossil Beds Rd, which has no signs whatsoever related to Rainbow Basin even though supposedly there's a sign for it if you're coming in the other direction. Once you find Fossil Beds Rd, you're on track, and there are signs for the rest of the way.

Is it worth bothering with all this? Absolutely! Geology Underfoot rightly recommends starting with the "scenic loop drive", a short, one lane, one way dirt road that looks a little rough but really shouldn't be a problem for any car (at least when dry). It winds down through narrow canyons composed of colorful highly tilted layers of mudstone and tuff, then up a little hill to a parking area which offers a panoramic view of the Barstow Syncline, where the rock layers have been warped by fault compression into a striking U-shaped depression in an action mimicking the larger scale raising of the Transverse Ranges north of the Los Angeles basin by the San Andreas fault.

Curiously, on an intensely crowded weekend, Rainbow Basin was almost deserted. At the Syncline parking area we joined one other vehicle, a white van belonging to the "Loma Linda Department of Natural Sciences (Geology and Biology)". We never did spot the Loma Lindans; presumably they were down in the syncline measuring strike and dip. I hope my class field trips turn out to be this interesting.

Geology Underfoot recommends following the scenic drive with a hike of Owl Canyon, from Rainbow Basin's camping area, so we did so. The Owl Canyon trail offers a chance to walk through the axis of the syncline, up a mostly-dry creekbed to a dry waterfall. The colors aren't as impressive as the layers visible from the scenic loop, but the more subtle colors are interesting: the book mentions the green mudstone all along the wash (green from weathering of volcanic ash, not from copper) but doesn't mention the strikingly colorful granites washed down into the canyon, reds and bright greens as well as greys and blacks.

Along the way, there's a short cave in the side of the canyon marking a tributary which runs in wet weather. The book recommends bringing flashlights if one wishes to explore the cave. Since we had only bought the book a day earlier, we weren't well prepared for that; fortunately, I had my little blue LED keychain flashlight clipped to my water bottle, which turned out to be fine since the cave was so short.

Rainbow Basin was an excellent conclusion to our Mojave desert trip. This well hidden pocket park is well worth a side trip if you're anywhere near Barstow and have any interest in geology, or just in a short scenic drive among colorful desert rocks. Assuming, of course, that you can find the road in.

Tags: travel, mojave
[ 21:31 Apr 03, 2005    More travel/mojave | permalink to this entry ]

Mojave

The East Mojave National Reserve is the nation's newest member of the national park system, signed into law as one of President Clinton's final acts. Growing up in LA, I'd driven through various parts of the Mojave desert since I was old enough to drive, but I hadn't been there since the park was created, and I didn't have much idea what specific interesting places might be there, except for Kelso Dunes, distantly visible from the interstate near Baker and always intriguing on our previous trips.

But where to go? I had no information about what was where, just an auto club road map and the topographic map collection I've been using to work on my pytopo program. The road map had ranger hat symbols at the town of Baker, at Mitchell Caverns down at the south end of the preserve, and at an obscure intersection of two minor roads in the south-central part of the reserve.

Dave didn't want to go to Baker -- it's a tacky little town whose two claims to fame are the World's Tallest Thermometer and a restaurant called the Bun Boy, though I have fond memories of our stay at Baker on the first night of our first trip together. Mitchell Caverns was too far and likely to be too crowded during spring break week. So we decided on the third option, which followed a road that led toward Kelso Dunes. Even if we didn't find a ranger station, at least we'd see the dunes; and there was an intriguing place somewhere along the road called "Hole in the Wall" which sounded worth checking out.

Roads in the preserve are mostly dirt, but are well graded and very well signed, and finding our way was no problem. Wonder of wonders, Hole in the Wall is the ranger station and campground marked on the auto club roadmap, and they have a very nice visitor's center and bookshop. Although they didn't have any books on the geology of the area (not their fault: no one has written one and they wish someone would!) they did have another in the "Geology Underfoot" series which covered, among other places, Rainbow Basin, tomorrow's target.

Newly armed with books and maps, we headed down the Rings Trail, Hole in the Wall's showpiece. It's short (though it connects to several much longer trails), fun and interesting: you scramble down over blocks of the colorful local tuff until you get to a steep slot, where metal rings have been bolted into the rock to provide handholds. Two such ring ladders and a bit more rock scrambling get you to the bottom of the slot canyon, where you can admire the fabulous colorful tuff towers above you, inspect the interesting tuff and volcanic breccia comprising the rocks, with their inclusions of hornblende, obsidian and other interesting minerals, and walk out to where the canyon emerges into normal Mojave desert with a view of the Providence Mountains and Mid Hills.

A very rewarding stop, and a fascinating place.

One curiosity about the Hole in the Wall Ring Trail: the sign at the trailhead makes a big deal about how strenuous the hike is. It's not really all that strenuous (the two ring climbs are short) but it could be unnerving for someone with poor balance or a fear of heights, too narrow for very overweight people, and of course it's not at all wheelchair accessible. But what they don't mention: if you drive south a few hundred feet on the road and turn west onto Wild Horse Canyon loop, in a very short distance you're more or less at the bottom of the Ring Trail. It's not as fun as climbing down the ring ladders, but would be well worthwhile for someone who couldn't see the canyon any other way.

With time left in the day, we took another route to Kelso Dunes, going back the way we came but by way of Wild Horse Canyon Rd, which the ranger recommended. I'm not sure why; there wasn't much on that road which we hadn't already seen from other roads. But taking the seemingly more direct route to Kelso, it turned out, involved quite a lot of slow jeep trail and probably would have taken quite a bit longer, so no harm done.

The highest of the Kelso Dunes rises to 600 feet, dwarfing the 140 foot rise of the famous Mesquite Dunes in Death Valley. Since I'd missed yet another chance to explore and photograph the Mesquite dunes a few days earlier, I was happy to be at Kelso.

The parking area was packed, but there's plenty of room on the sand: it wasn't crowded away from the parking lot. Getting to the dunes involves fighting for some portion of a mile along a deep sandy trail, then scrabbling your way up the side of the dunes.

The dunes are covered with wind ripples and tracks of all sorts of animals (mostly lizards, insects, hikers, and their dogs and children) and plants (the dune grass bends in the wind, and the tips of each blade make an arc in the sand.)

Near the top, you start feeling like an Everest trekker: you eye the cornice of sand along the ridge to the north, and watch the turbulent eddies of sand blowing off the tip of the peak above you as the wind howls past and threatens to blow you off the mountain. Well, okay, admittedly it's a bit warmer and you don't need oxygen tanks.

We went as high as the Hillary Step, but Dave's eyes were protesting from too much sand under his contact lenses, and the wind got worse with every foot ascended, so we stopped there. Our sherpas had long since deserted us.

Descending is much quicker than ascending. For one thing, you can take giant moon leaps, or "ski" down the sides of steep slopes, if you don't mind getting your shoes full of sand. Alas, the long level slog from the base of the dunes back to the parking lot is no easier in the return direction.

We drove out via Kelbaker Rd, past perhaps the most perfect collection of cinder cones I've ever seen together in one area. The map says they have a lava tube there, too. We'll have to come back and check it out some time.

Tags: travel, mojave
[ 08:26 Apr 01, 2005    More travel/mojave | permalink to this entry ]

Fires of the Aztecs, Fires of the Earth

Valley of Fire State Park, in Nevada, is in the Lake Mead National Recreational Area near the northeast end of Lake Mead.

It's an auspicious location, because the Valley of Fire exit from interstate 15 is at the trading post run by our favorite local Indian tribe, the Moapa. In addition to not-completely-unreasonable gas prices and a huge assortment of fireworks, they sometimes have a trailer outside the store from which they sell "Really Good Beef Jerky" (it says so right on the sign). It really is "really good", the best I've had anywhere, even though it turns out to be imported from Wyoming and not made locally by the Moapa. Dave and I always look for the jerky trailer when we're passing through.

We had some idea what to expect from the Valley of Fire, because on a recent trip we stumbled upon an excellent little rest area north of Lake Mead called "Redstone", which included well made interpretive signs explaining that the deep red rock was Aztec Sandstone.

Indeed, the Valley of Fire is Aztec Sandstone, whose fiery color inspires the name; but the park turned out to be sizeable and varied, full of color changes and scenic vistas, excellent petroglyphs, and, oh, yes, a wildflower assortment that puts Death Valley's celebrated wildflowers to shame.

We expected a quick drive-through, but had no trouble whiling away the entire day in the park, including three short hikes and a lot of happy scrambling over rocks. It's comparable to the excellent Arches national park near Moab, in size, variety, and character. The Aztec even forms arches like the Entrada above Moab, though it tends toward lots of small arches rather than the big sweeping spans of the Entrada.

Unlike Arches, though, it isn't terribly informative (Arches being surprising good about explanations compared to most national parks). The Valley of Fire's signs and visitor's center are rather light on details. Why is the sandstone so deeply red in some places (well, iron, sure, but why so much more iron than other places?) and white or bright yellow in others? Why is it called Aztec? What makes the seams/dikes which are so prominent in the white formations near White Domes area? Is it just coincidence that Aztec and Entrada sandstone, both so intensely red compared to most sandstone, also share the unusual property of forming arches?

The visitor's center has a decent geology timeline with stratigraphic columns and a diagram of the fault as a fixed exhibit, plus kiosks with photos of common flora and fauna, but nothing you can take away with you, and they sell no books beyond lightweight coffee table fluff. "Sorry -- we keep telling them they should make something like that," apologized the lady at the gift shop counter.

We had just enough light left after leaving the park to make a quick trip down a dirt road to a ledge overlooking the north end of Lake Mead. The lake level was quite low; the ingress of the lake was far downstream of the location given on the map. Last summer, the LA Times reported that Mead was at record low levels, and the lost town of St. Thomas, submerged since the reservoir was first filled, had reappeared, delighting archaeologists and historians. I'd assumed that this was long past, after this year's unusually wet winter, but the lake level was still quite low: and at the St. Thomas overlook, several objects looking like the tops of buildings peeked out from beneath the water's surface. Further research will be required to find out whether we actually spotted St. Thomas.

Tags: travel, mojave
[ 08:55 Mar 31, 2005    More travel/mojave | permalink to this entry ]

A Mosaic of Flowers

Passing through Death Valley wasn't the point of our Mojave trip, but it seemed like a nice bonus. Everyone's been talking about how due to the unprecedented southern California rains, this spring is a record year for wildflowers in Death Valley.

Of course, what that really meant was that everyone in the western half of the US decided to spend their spring break week there. Stovepipe Wells was a zoo.

But I wanted to see Mosaic Canyon, rumored to be a good slot canyon, and favored in "Geology Underfoot: Owens Valley and Death Valley" for breccia containing fragments of the precambrian Noonday dolomite.

It's a fabulous canyon. The book got so involved in talking about the breccia and stream undercutting that it didn't mention the gorgeous, smooth, veined, water-cut dolomite comprising a long and narrow slot canyon for the first half mile or so of the hike. Farther upcanyon, warping caused by the Mosaic Canyon fault creates impressive exposures in the walls.

After reluctantly leaving Mosaic Canyon, our route led us down the Badwater road, where the fabled wildflowers were impressive in number, if not in color (almost all yellow, with a few small whites and pale purples). The photographers, too, were impressive in number if not in intelligence, tending to back into the roadway in front of traffic at unpredictable times. The fields were full of people looking for just the perfect flower for their shot.

I'd heard rumours that Badwater was flooded, to the point where people were kayaking there. Not true: the water wasn't deep enough for kayaking, but the shallows were full of families and couples wading barefoot in the brine. We didn't wade, just walked to the water's edge and admired the new incarnation of ancient Lake Manly, the huge lake which once filled all of Death Valley, sparkling in the sun.

South of Badwater the flowers were a little denser, but didn't change very much in character until we left the park, where yellow coreopsis gave way to bushes covered with bright orange dodder, a parasitic plant that I think of as "silly string plant" because it covers other plants with a thin, bright orange string that looks like "silly string" sprayed out of cans.

Our last stop was just a few miles east of the town of Shoshone: a roadcut highly recommended by the Geology Underfoot book, which devoted a whole chapter to it. Rightly so! A strikingly weird black stripe which appears to be a coal seam is clearly, upon closer inspection, a layer of obsidian sandwiched between red rhyolite layers with interesting inclusions. Both the obsidian and the rhyolite includes bits of quartz. A little farther up the roadcut, past the obsidian, are two striking vertical faults. Quite amazing, and I'm glad we made a point of taking that route.

Tags: travel, mojave
[ 22:30 Mar 30, 2005    More travel/mojave | permalink to this entry ]