Sunday, August 7, 2011

A Convergence of Wonders, Day 15: We Head Underground in the Great Basin

It was Day 15 of our Convergence of Wonders journey in the Pacific Northwest and Northern Rocky Mountains (June 29th). Being only a day from home, we had actually left the PNW and Rockies far behind, and we would be traveling upwards of 500 miles on this day to get as close to home as was practical. We were crossing the vast, mostly barren expanse of the Basin and Range Province in western Utah and eastern Nevada on America's "Loneliest Highway".

People may be forgiven for thinking that "lonely" equates to "uninteresting". I know differently, having gone to college in Reno, and doing some extensive geo-touring across the region. Silver Fox, over at Looking For Detachment, understands this as well, and is a great resource for understanding some of the incredible geology to be found in this unique landscape. Unfortunately, it had been two weeks of hard traveling, and it was getting harder to rouse the troops! But two stops caught everyone's attention.
We drove the two hours from Topaz Mountain to Great Basin National Park near Ely, Nevada. We found a nice spot under a huge cottonwood tree at the visitor center to talk about the park's geology. It's rich, and I will have more to say about it in the future. But the park's centerpiece is Lehman Cave, and we were going on a tour.
Of course, we needed a guide, and we heard the usual thing one always hears: "Don't Touch Anything!" Of course, such admonitions are necessary, as caverns are one of the most fragile environments to be found anywhere. A single broken stalactite will take centuries to grow back, if ever (many caverns are not active...few parts of Lehman Cave have any water at all). In the earliest days, cavern explorers took a stalactite as a souvenir. More than a million people have now toured the cave...how would the cave look if even a fraction of that many people broke something off and absconded with it?
Luckily many of the cavern's decorations, called speleothems, are still intact. There are rich examples of dripstone speleothems, like the familiar stalactites, stalagmites, and columns. Photographing caves and cave features is always a challenge for me. Flash can be used, but such pictures are often washed out and have little depth. I try to use the provided light when I can (I almost wrote "natural light", but that would be silly to say). Tripods aren't allowed on the tours, so I braced the camera on the railing for the pathway, and used a 2 second delay on the shutter so the pushing of the shutter release wouldn't shake the camera.
 Here are lots of the familiar dripstone features...
Lehman Cave is unique for the 300 or so cave shields that are found within. They are only found in about 80 other caves around the country (out of thousands). The shields can be thought of as two fossilized cymbals, two large disks separated by a thin crack. Their origin is not well understood.
 There's another shield in the little alcove below...
 And a pair of shields in a solution tube...
The cave is well worth the long journey. And there are many other features that make Great Basin a unique destination. Unfortunately, the tour ended, and we were in a hurry to get across the desert.
We made a brief stop at the Baker Archaeological Site, a village on the desert floor that is the westernmost Fremont Culture site so far discovered. The site itself is unremarkable to see (it was excavated years ago and no artifacts are displayed), but the view of the Snake Range and Great Basin National Park is spectacular.
We made a gasoline stop in Ely, the metropolis of eastern Nevada (around 4,000 people), and headed up the hill near Ruth, Nevada to search for some more gemstones. This time our target was the garnet crystals of Garnet Hill. Most geologists probably associate garnet with metamorphic rocks, but on Garnet Hill, the gems are found in a rhyolite intrusion/caldera complex that is very similar to the rocks that hosted the topaz crystals that we found in Utah the previous day. The federal Bureau of Land Management set aside the site from mineral claims to keep it accessible to casual collectors like ourselves. It's at the end of a three mile dirt road which is usually passable for passenger cars.

There were different strategies for finding deep red garnet crystals...one could pound rocks open with a rock hammer, and use a lot of calories and sweat, or one could let the car traffic do the work for us. There are enough crystals that car tires break the gems out and they can be discovered by simply walking along the road watching for dark spots.
The crystals display very nice faces. They look black, but if you look closely (click on the photos), you can make out the rich deep red color (this variety is called almandine garnet).
These specimens are pretty small, less than a quarter of an inch, but I have seen some found here nearly an inch across.
It was getting on towards 3 o'clock, and we still had something like 250 miles to go, and it was going to be sundown when we arrived at camp, if everything went right. Everything didn't...

It wasn't our accident, but some motorcyclists lost control in the heavy winds that were buffeting the highway and crashed, and we had to wait for ambulances to come and clear the scene. Apparently no one was dead, but the traffic was blocked in both directions for well over an hour, so we were suddenly grievously behind schedule
Instead of waiting until late in the evening for dinner, we stopped in Eureka and invaded their few restaurants. 180 miles to go, and the sun was hitting the horizon. There were storms all around us, and the skies were glorious. The sunset was one of the more beautiful ones we saw this trip, but we couldn't stop for pictures.
We rolled into camp at Berlin-Ichthyosaur State Park just before 11 o'clock and set up camp for the last time. Tomorrow we were going home. And yet still more treasures lay ahead on the road. That will be the subject of the next and final post of this series!
The sunset and storm pictures are courtesy of Mrs. Geotripper.

5 comments:

Charles said...

Loved this post! Sorry the trip's coming to an end. Thank you for sharing.

Silver Fox said...

Good photos inside Lehman. I haven't been on a tour when they allowed flash, and have not been as successful as you at bracing the camera.

Looking forward to Berlin-Ichthyosaur.

Gaelyn said...

Haven't yet made it to Lehman Cave. Caves are difficult to photograph without a tripod.

Great garnet finds. And awesome sunset shots Mrs. Geotripper.

I'm sure everyone was glad to be heading home. Yet this was an Awesome trip!

Lyle said...

Did you go by Notch Peak in Ut? Of course going West it is not as spectacular as going east but its still the second highest cliff in the US after El Capitan. Going East you see it a long way away and it really stands out.

Garry Hayes said...

Notch Peak is a spectacular cliff! We could see it from the highway, but I couldn't get a good shot of it. We camped in the canyon at the base of the cliff when I was working at the UNR field camp 25 years ago.