Fun amidst the Fumaroles

More illustrated musings from my highly enjoyable, educational and flat-out fun little jaunt to the eastern Sierra country…

Several days ago I posted about Mono Lake and its tufa towers. Over parts of two days, I also roamed the floor of the Long Valley Caldera from Mammoth Mountain to frozen Crowley Lake and all around, before, during and after the Sierra dawn, and through the cold and lonesome Western back roads, and over some of the most fascinating hot streams any side of Yellowstone.

If it looks cold, that’s because it was! Temperatures were near zero Fahrenheit in the mornings, just below freezing in the afternoons. However, for one of the few times in memory, I didn’t care very much and was dressed for the occasion — that is, except for when I kicked off the boots or rolled up the sleeves for a soothing little dip in the steamy mineral waters. I spent a couple of hours just wandering along the hot streams that feed “Hot Creek”, near but unfortunately not within the Hot Creek Geologic Area (which was closed and inaccessible).

In particular, the patterns and thickness of the hoarfrost, already of an uncommon geothermal origin, truly captivated me for quite some time. If the slides turn out as well as the low-res digital pictures, then I’ll have some new additions for the SkyPix Water Works gallery. Indeed, in a rare experience, I was able to immerse in all three phases of water (solid, vapor, liquid) at once!

Long Valley Caldera is the other active volcanic caldera in the United States, besides Yellowstone. Like Yellowstone, its form arose from catastrophic eruptions, the last a little over 730,000 years ago (somewhat before Yellowstone’s most recent blast). Some of the ash from that eruption blew as far east as Kansas and Nebraska, but most of it fell in the general area as a formation called the Bishop Tuff (which I collected, along with more recent basalt samples and other rocks). Like Yellowstone, earthquakes are common (though I didn’t experience one…rats!), as are geysers and fumaroles, and a massive eruption certainly is possible.

Unlike Yellowstone, which sits atop a midcontinental “hot spot,” Long Valley’s fuel is supplied by plate tectonic interaction between North America and the Pacific. Mammoth Mountain sits in the western part of the caldera and is itself a large pile of basalt and other igneous rock — a composite volcano. The ski area sits atop the western part of a huge dome of magma, not far underground, that awaits the next big eruption. Until then, the moving liquid rock causes releases of steam from many fumaroles, occasional earthquakes and even plumes of suffocating gases. A chain of volcanic vents extends northward into Mono Lake, even forming the lake’s Pahoa Island. Some of these vents have erupted as recently as about 600 years ago, and more may start to spew their ejecta at any time.

I wouldn’t want to live there, but Mono Lake and the Long Valley area is a fascinating place to collect rock samples, explore geological marvels and do some unique photography. I hope to have the opportunity to return.

[All linked photos strictly (c) 2006 Roger Edwards, All Rights Reserved.]



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