The breathtaking geology of the Sierra Nevada micro mountain ranges


I was recently driving north on Hwy 395 on my way home after spending Thanksgiving in Southern California. I have walked this route countless times, crossing the eastern edge of the Sierra Nevada from the mountains to the ocean and back again. The sight never gets old.

As an earthling, I sometimes struggle to grasp the full magnitude of the planet’s most extensive features, like this 400-mile-long mountain range. That’s why I love maps, because they help me visualize and connect to things that are so much bigger than me, on a scale that is hard to imagine otherwise. This is why I fell in love with rock climbing, as climbing smooth granite and volcanic rock with holes was a way to experience all the textures and characteristics of different types of rocks. This is also why Hwy 395 is my all-time favorite route, as it offers such a spectacular, holistic, and panoramic view of some of the highest mountains in the country, including Mount Whitney, with its peak towering at 14,505 feet above sea level. Isn’t it crazy that a person could see the highest mountain of the Lower 48 from the front seat of a car going 60 miles an hour on a freeway, so many miles below the summit?

But recently I learned something new about this mountain range that I thought I knew so well.

Sierra Nevada is not a giant monolith in a huge mountain range. These mountains have nuances and a deep geological history, says Jim Faulds, professor of geology at the University of Nevada Reno and state geologist and director of the Nevada Bureau of Mines.

In some places, Faulds explained to me, the Sierra Nevada is actually made up of smaller mountain ranges that protrude from the main ridge, like long fingers pointing towards the sagebrush-strewn deserts of the Great Basin.

This is why the eastern shore of the Lake Tahoe basin looks so different from the western shore. The East Rim of Tahoe is a totally different mountain range from the West Rim. It’s not Sierra Nevada. This is the Carson range. The enormous amount of water in Lake Tahoe bridges the gap between the two mountain ranges.

The western shore of Lake Tahoe is just below the Sierra Nevada ridge, which stretches south, to Yosemite, to Bishop, to Lone Pine. On this side of the lake, the mountains are higher and steeper. The west shore often receives more snow than the east shore. This side of the lake is also generally deeper than most parts of the eastern shore.

The east bank, on the other hand, is drier. He feels more sterile and open. Its peaks are rounded, less jagged than the peaks crossing the lake.

Looking north along the eastern shore of Lake Tahoe and the Carson Range.

PictureLake / Getty Images

Faulds explained to me how it happened. It has to do with a fault line that goes under Lake Tahoe and articulates up east that created the Carson Range. This fault line is also why the west shore near DL Bliss State Park is the deepest in Lake Tahoe.

“The Sierras are really fascinating,” Faulds said. “They are also part of the history of the earth and the geology around them. “

There are other micro mountain ranges in the Sierra Nevada, such as the Crystal Range in the Desolation Wilderness with its barren granite lunar landscape and lakes.

In Reno, an isolated mountain called Peavine rises to the north. Faulds stated that Peavine has its own history and identity which is both distinct and linked to the Sierra.

“We’re putting together a detailed map of Peavine right now,” he said, “to determine his anatomy, if you will, and why he’s there. Of course, like anything you take a closer look at, it’s more complicated than you might initially think.

West of Peavine and northeast of Truckee, the Verdi Range forms along another fault line and these mountains are also part of the Sierra Micro Mountain Range Network.

In Susanville, the Diamond Mountains emerge from several fault lines, separated from the central part of the Sierra Nevada.

“All of these little mountain ranges that make up the Sierras generally, almost all of them are there due to relatively recent faults,” Faulds said.

However, some features of the Sierra are much older than the entire mountain range. Like the Sierra Buttes in the Lost Sierra and the Minarets near Mammoth. Both are easily recognizable ridge lines because they are so distinct from the rest of the horizon. They are jagged and jagged and sharp. The reason they look like this is because their rock is harder and stronger than the rock that formed the rest of the Sierra, Faulds said.

“They are stronger than the granite around them,” he said.

So if there are all these nuances, micro-details and distinctions throughout the 400 miles of Sierra Nevada, why do we lump them all together and insist that they form one gigantic mountain range? ?

Faulds said he thinks it’s a matter of scale.

“The Sierra Nevada is an incredible, long, continuous mountain range – connected high altitude ranges,” he said. “You watch it from space and it looks consistent. But then you go down to 30,000 feet and you can see there are all these little arms and individual staves pulling over most of the Sierra.

Those who live in these places know these distinctions intuitively. Geology helps make a connection between this connection and an understanding of a place, so it makes sense that the East Rim of Tahoe is a separate mountain range from the West Rim.

Back on Highway 395, dusk set in as the road dipped into the Carson Valley, behind the Carson Mountain Range. From here these mountains look so high. But on the other side, from the view inside the Tahoe Basin, the Carson range looks smaller. Now I understand better why these mountains look like they are. But it always makes me dizzy to think about how much water they are holding in Lake Tahoe.


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