Favorite field sites: the Sierras
Dave at the Geology News blog is hosting this month's Accretionary Wedge on the topic of "favorite places to do field work."
My favorite place to do field work is in California's "range of light," the Sierra Nevada.
I did my geology master's field work in the eastern Sierra, along the Sierra Crest Shear Zone, a major high-strain zone which parallels the eastern edge of the Sierra Nevada Batholith through older meta-sedimentary and meta-volcanic host rocks.
In 2003, I spent the summer out there, starting with my first field area at lovely Gem Lake:
An angular unconformity can be seen in this image as the tilted (close to vertical) metasedimentary and metavolcanic rocks (orange and gray) are overlain by dark colored "Tertiary" basalt flows. A big talus slope of basalt chunks makes a black triangular shape that heads downhill toward the lake. In the distance, where the land rises appreciably, the granites (and granodiorites) of the batholilth begin.
We camped on this peninsula sticking out into Gem Lake:
Dazhi Jiang (Then of UMD-College Park; now at the University of Western Ontario) and USC's Geoff Pignotta examine strained metavolcanics near Gem Lake:
Here's me with the Ritter Range in the background:
Glacial striations sculpting my strained metavolcanics:
Field gear:
Here's Bench Canyon, where I went off alone and did field work for a week. In retrospect, going solo was probably pretty dumb. I was off alone in a trail-less area, at times ten miles from the nearest trail. I took a tumble on the rocks one day, and thought "Yikes. Nobody knows exactly where I am, and no one would even come looking for a couple of weeks or so." Glad I hadn't broken my leg, I hiked back to camp chastened and on high alert:
There, the Cathedral Peak Granodiorite shows awesome orthoclase (potassium) feldspar phenocrysts, so large they are called "megacrysts":
A third field site: the Mono Pass area. Again, the rocks' colors show the metamorphic host rocks in the foreground, and the batholith (in this case, the Kuna Crest Granodiorite) in the background:
USC's Scott Paterson was kind enough to introduce me to the geology of my fourth field site, the Saddlebag Lake area. Here, Scott shows me and two field assistants the contact between the Cathedral Peak Grandiorite and the host rocks:
My favorite place to do field work is in California's "range of light," the Sierra Nevada.
I did my geology master's field work in the eastern Sierra, along the Sierra Crest Shear Zone, a major high-strain zone which parallels the eastern edge of the Sierra Nevada Batholith through older meta-sedimentary and meta-volcanic host rocks.
In 2003, I spent the summer out there, starting with my first field area at lovely Gem Lake:
An angular unconformity can be seen in this image as the tilted (close to vertical) metasedimentary and metavolcanic rocks (orange and gray) are overlain by dark colored "Tertiary" basalt flows. A big talus slope of basalt chunks makes a black triangular shape that heads downhill toward the lake. In the distance, where the land rises appreciably, the granites (and granodiorites) of the batholilth begin.
We camped on this peninsula sticking out into Gem Lake:
Dazhi Jiang (Then of UMD-College Park; now at the University of Western Ontario) and USC's Geoff Pignotta examine strained metavolcanics near Gem Lake:
Here's me with the Ritter Range in the background:
Glacial striations sculpting my strained metavolcanics:
Field gear:
Here's Bench Canyon, where I went off alone and did field work for a week. In retrospect, going solo was probably pretty dumb. I was off alone in a trail-less area, at times ten miles from the nearest trail. I took a tumble on the rocks one day, and thought "Yikes. Nobody knows exactly where I am, and no one would even come looking for a couple of weeks or so." Glad I hadn't broken my leg, I hiked back to camp chastened and on high alert:
On the way to the Bench Canyon field area, I passed by this lovely waterfall, Hemlock Falls (in the Ansel Adams Wilderness area):
Later, I was up in the Tuolumne Meadows area, and hiked to Cathedral Peak:
There, the Cathedral Peak Granodiorite shows awesome orthoclase (potassium) feldspar phenocrysts, so large they are called "megacrysts":
Working the GPS with an injured thumb:
A third field site: the Mono Pass area. Again, the rocks' colors show the metamorphic host rocks in the foreground, and the batholith (in this case, the Kuna Crest Granodiorite) in the background:
USC's Scott Paterson was kind enough to introduce me to the geology of my fourth field site, the Saddlebag Lake area. Here, Scott shows me and two field assistants the contact between the Cathedral Peak Grandiorite and the host rocks:
Here's a view out over the Saddlebag Lake area (looking north), showing yet again the strong color difference of the metamorphic rocks to the east and the light-colored granitic rocks to the west. Greenstone Lake is in the mid-ground:
All in all, I loved my time in the Sierras. It's a fantastic range of mountains with a host of beautiful landscapes and superb geology.
Labels: california, field trips, glacial landforms, granite, igneous, metamorphism, structure, travel
2 Comments:
Nice post and pictures, especially of the megacrysts! I also really enjoy the area around Saddlebag Lake.
Additional link: John Muir explains why he calls the Sierras the "range of light" (from the Atlantic Monthly, 1899, as quoted in the Yosemite Blog.
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