Friday, July 22, 2011

July 2011 Road Trip II: Winnemucca to Alvord Desert

A good night’s rest. A bed after the long commute was wise.

Since I’m running a marathon at the end of the month, training must continue. Thus at 6:55 am, I parked Trixy (my reliable 2005 Toyota Matrix) at the east end of 2nd Street: the edge of town. Running through the quiet town early on a Sunday felt right. I set off into a moderate headwind, past old solid looking houses; a two story apartment was signed, “Built in 1912”. Past the town hall, the county field office, Winnemucca Junior High. Eventually the west end of town appeared, so I turned south, uphill and over the railroad lines. More vehicles on this road; mostly large American pickups. Putrid diesel breath. The road took me into new Winnemucca; cheaper-looking modern houses, apartments. I passed a woman walking her dog, talking on a cell phone. She mouthed “good morning” as did I. Turnaround and return via 4th Street 3rd Street, and 2nd Street. Many barking dogs, all toy-sized. 3.3 miles in 28 minutes. Not bad for this altitude.

Breakfast and departure, leaving I-80 for Rt. 95 N. Winnemucca vanished quickly: back into the Basin and Range. I drove north up the Pueblo Valley, turning west on Rt. 140. Again, out of town, but not out of civilization; the valley margins were sparsely dotted with ranches, the homesteads marked by clusters of cottonwood and Italian cypress trees. The valleys are high enough here for limited agriculture, evidenced by industrial-scale irrigation systems spraying water in the still cool morning. No cattle – too little water? Over a low pass, and the next basin dropped into semi-desert. A return to sagebrush.

A right-hand, northward turn at Denio and I was in Oregon. Good bye to wide road striping. Over a rise, and there was Steens Mountain. I swerved at the sight of 5,000 feet of craggy ridge, the top still bearing snow, the effects of glaciers (long melted) clearly visible. This is the biggest and highest mountain in the Northern Basin and Range Province – upwards of 30 miles long.

I’ve been itching to write about the Basin and Range. As I wrote earlier this physiographic province includes much of Arizona, Utah and Nevada, and bits of Mexico, California, New Mexico, Colorado, Idaho, Montana, Canada, and yes, Oregon. This geographic definition keeps expanding; New Mexico and Montana weren’t on the list when I was in grad school. I first became aware of the region while in college, from staring at a geologic map of North America. On it, the north trending, colored ranges looked like a fleet of aligned caterpillars amid the yellow tan colored alluvial basins.

Of course, this geography is controlled by the underlying geology, just the way I like it. The Basin and Range is clearly an area of major extension – widening – of the North American plate. Imagine stretching the bellows of an accordion, and you’ll get the idea. The amount of extension is crazy – 50% to maybe 200% - and is way beyond normal for the Earth’s plates. The geologic origin of Basin and Range extension is controversial. Given that it involves large-scale tectonics and structural geology, it’s way beyond my expertise. Not that this will stop me from making a shot at an explanation.

For much of the past 450 million years, the western edge of the North American plate – what’s now Mexico through California, Oregon, Washington and British Columbia – was a convergent plate boundary, similar to the current west coast of South America. This was a zone of overall compression, as the plate overrode the oceanic crust to the west. This long-lasting process made the North American crust relatively thick. At the same time, subduction of the oceanic crust created the granites and other igneous rocks of the Sierra Nevada, among many others along the boundary. However, starting about 20 million years ago, a divergent plate boundary – a mid ocean ridge – began to be subducted under North America. Divergent plate boundaries are areas where two plates spread –extend – way from each other. It’s weird for one to be subducted. As the mid ocean ridge was forced under North America, subduction apparently slowed and stopped. This lead to creation of the modern plate boundary, the San Andreas Fault System, but that is another story I barely understand.

On to the Basin and Range. So, no more subduction; this may have allowed relaxation of the compression western North America had been enjoying for so long. It’s possible that this allowed the crust to spread from its thickened state back towards “normal” (a poorly defined term). This sort of extension certainly happens and has happened elsewhere on the Earth, but as far as I know, there’s still only one Basin and Range. The joker in the deck might be the subduction of the mid ocean ridge. Divergent plate boundaries are also sites of active igneous rock formation – seafloor volcanoes and intrusive rocks. In other words, they’re hot. When the ridge went under North America. this heat, formerly concentrated along the plate boundary, must have begun to warm the overlying crust of North America. Warmer rocks are softer and more prone to flow; this may have aided the relaxation of compression I described. Or vice versa, or simultaneously. There are more ideas, but this should be enough to give a sense of the large scale forces involved. I always get shivers when I think about what happened, over millions of years. It’s awesome. Having any understanding is a humbling and ultimately spiritual thing; it’s one of the key things that drew me to geology.

The geography of the Basin and Range is the surface expression of this extension, plus the effects of erosion. As the plate pulled apart, the upper, brittle part of it was complexly faulted, such that large blocks of real estate dropped down – forming the basins – while other rose and/or were left high – the ranges. The precise geometry of the faults is massively variable and complicated. Accompanying this spreading was intermittent volcanism – magma leaking up along cracks, lots of mineralization, and to this day, abundant geothermal activity; hot springs. I’m hoping to see all of these on this road trip.

The 140 brought me to the micro-town of Fields. Every Oregon travel guide that I read truly raved about the milkshakes at Fields Station – the local motel/campground/store/gas station/restaurant. It was 11 am. I entered the store; the milkshake bar called to me. Chatting up the owner, she recommended a coffee caramel shake, one of her creations. I order one, and sat and talked to her granddaughter and grandson (he had topped up Trixy’s gas tank, not bad for a nine-year old). The boy pointed out a can of rattlesnake meat on the bar, and said, pick it up. When touched, it immediately began to vibrate. He began to proudly tell me how he’d wired up a motor inside to fool customers, but was called away to the gas pump. Not to be outdone, his sister gave me a tour of the pictures that covered every vertical surface in the store. This is hunting country; they all featured men, guns, and their quarry. And a few pictures of local rattlesnakes. The shake more than exceeded its publicity, but at 24 oz., I was wired; more dairy and sugar than I eat in a week. Well, this is vacation, right?

I’d come to Fields in hopes of visiting the Alvord Desert, a particularly low basin that’s filled with a very large dry lake. It’s just to the east of Steens Mountain, and sounded scenic as hell. My BLM pamphlet was ambiguous about road quality, but Grandma assured me that the road was good.

Onto gravel, at a stately 25 mph. I’ve driven Trixy on gravel before, but this was a new road in a new state, and I vigilantly wanted to avoid any car trauma. Sigh, this is the one time of year I’d truly love to have a good 4WD Landcruiser. No fear. The Alvord Desert appeared to the east, just off the road. A bright buff expanse, already cooking in the midday sun. I really wanted to get out on the playa, but wanted to complete some recon first.
My guidebook made vague reference to an informal camping area about 25 miles into the Desert. I eventually found the track, and crept up it, climbing the alluvial fan of Pike Creek, which drains the east side of Steens Mountain. I gingerly dodged the cobbles and boulders protruding through the gravel, all to save Trixy’s tires and delicate underbelly, eventually reaching a point of bouldery steepness that scared me. I backed down the road, pulling into a campsite I’d noted on the way up.

1:30. I wandered up the track to Pike Canyon, and found a nice flat boulder of volcanic rock to sit on at the base of the Mountain. It was time to break the pattern of motion and action, and contemplate. A strong southerly wind blew along the range, at times overwhelming the buzz of locusts in the brush. I liked the rushing noise it makes blowing through the sage. The rock was warm; matching the intensity of the summer sun; I was glad for my SPF 70.

Alvord Desert continued to glow buff-white in the distance. Intermittent dust devils spun up the east side. I’m glad I wasn’t out there; some of them must have been a couple thousand feet high. The Alvord is collared by a band of green; I presume there’s enough shallow groundwater to sustain a decent plant cover. And animals; I eventually heard a solitary moo, indicating that the dots I’d been watching were actually cattle.

My mind still rushed with thoughts of the past, present, and future, but sitting helped, as I began detachment from the factors in my life that aren’t here. My shadow gradually lengthened; time to wander downhill and use the afternoon light for photography.

Back to Trixy, dinner, a spit bath, and sleep.

1 comment:

  1. SHassler,

    I was just at the Alvord during the third week of June with some friends. To our surprise, she was completely underwater! I read your most recent blog post from Friday and didn't read anything that mentioned water. Was the lake bed dry or still a lake when you were there?

    Check my friend Cameron's photos in Facebook here to see:

    Let me know what conditions you observed while you were there. Cheers, Kevin Balmer