Carson Rocks! October 11, 2014

19 Oct

Dalan and I joined a UNR (Univ. of Nevada – Reno) and Nevada Bureau of Mines & Geology sponsored tour in honor of Earth Science Week.  We always want to learn more about our area and this was free, so why not? The purpose of the tour was to explore the interactions between Earth’s geosphere, hydrosphere, atmosphere and biosphere as we explored several sites around Carson City. This is what we did …visited several sites where we examined and collected a variety of interesting rocks that help earth scientists explain the geologic history of the area.

Dalan looking for the greenish epidote

Dalan looking for the greenish epidote.

Some epidote with tiny garnets mixed into it.

Some epidote with tiny garnets mixed into it.

About 50 people joined this tour, many with a lot of geologic knowledge. Dalan probably knew more than I. But I listened and learned a lot. Our first stop was Lone Mountain where we collected epidote, quartz and garnets. I learned that Nevada is one of the most seismically active states in the U.S. — second only to California in the lower 48 states. Historically, we have experienced a magnitude 7 or greater earthquake about once every 30 years. The last ones were in 1954 near Fallon. So I guess we’re due for a good one.

A front was quickly moving through the area and the cloud formations were changing constantly. I thought this picture was pretty neat. There is even a tiny rainbow in the center left portion.

An interesting cloud formation

An interesting cloud formation

We went up into the mountains on the north side of Carson City where we espied 14 wild horses as well as many more rock samples. Some of the big boulders (called volcanic bombs because they were ejected quite a distance from the actual cone) pinged different sounds due to their composition. We thought that was pretty cool.

We visited a volcanic vent that is only 1.1 million years old (young geologically speaking) that is being worked by a company called Cinderlite. They use scoria, basalt and other cinder cone contents for landscaping jobs. Cinderlite realized that eagles were nesting in a couple of holes in the cinder cone and decided not to destroy that area. So now there is a large 100’ by perhaps 40’ by 100’ tall area where the birds are free to nest. I think that’s a nice gesture by the company.

The cinder cone with the aeries on the center top

The cinder cone with the aeries on the center top

It's evident these aeries have been used for many years

It’s evident these aeries have been used for many years

Dalan got a little bored with all the explanations and did some of his own exploring. He made me a little nervous climbing over many huge rocks, but he was sure footed and got to see more views than I did.

Dalan with his rock hammer

Dalan with his rock hammer

One of our stops took us to a divide between watersheds. If you stepped to the right, the water drained into Washoe Valley. If you stepped to the left, the water drained into the Carson Valley toward the Carson River. I thought that was cool. Also in this area was what geologists call an “unconformity.” Basically, it is the contact between two rock types with a large gap in age. The granodiorite (GD) is about 100 million years old and the overlying basalt is about a million years old.  I first heard of this in the Grand Canyon but never quite got the concept of it until now. I mentioned granodiorite. We know it as decomposed granite and it’s used a lot around here on playgrounds, in landscaping, trails and whatnot.

As we looked west, we could see, obviously, the Sierras and some of the active fault system along the base of the mountains. We were told that as faulting progresses,, the mountain front steepens, the slopes become unstable and landslides occur. We can see that on Slide Mountain, the white spot in the center of the picture. A massive landslide happened there in 1983.

Slide Mountain and Mt. Rose in the background with Washoe Lake in the foreground.

Slide Mountain and Mt. Rose in the background with Washoe Lake in the foreground.

Carson City view from the watershed area.

Carson City view from the watershed area.

Again, I have probably made this too detailed and historical. I hope you haven’t been bored by these details.

The field trip was very educational and fun to see things up close and personal.  I hope they have another one next year during Earth Sciences Week.












































One Response to “Carson Rocks! October 11, 2014”

  1. Schildmeier October 19, 2014 at 8:22 pm #

    Boring? Too historical? Not a bit!, Cora I loved reading this edition of buzzardnotes, as I loved readiing all it’s procedors. Are there actually still wild horses in the United States? I saw the movie “Misfits”, one of the last pictures with Marilyn Monroe and Clark Gabele. But that was taken quite a few years ago, so I’m happy to read that you can still find them. I especially liked the part about the watershed. We have a watershed ricght in Bargteheide. There is a main traffic road passin gthrough our town. On the Western side of the street the rain water runs into a system of pipes, ditches, and creeks into the Alster River, then into the Elbe River, and to the North Sea – which is part of the Atlantic Ocean. The water on the :Eastern side goes via the Trave River into the Baltic Sea. Before they put on that sign, I didn’t ever think at all about where the water goes. Isn’t it cool, though, once you know! Love, Angel

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