Saturday, August 22, 2009

Spotlight on California Geology: Geology of Sequoia and Kings Canyon

The southern Sierra Nevada is somewhat less familiar to most travelers than the heavily visited Yosemite/Lake Tahoe region, but contains some incredible scenery and fascinating geology. The Far West Section conducted a series of field trips there in the fall of 2005.

Two national parks grace the region: Sequoia and Kings Canyon. Sequoia is the oldest of the two, having been established in 1890, with Kings Canyon following in 1940. They are administered as a single unit by the park service.

Sequoia preserves the Giant Forest and other groves of the Giant Sequoia trees, the largest living things in the world. Within the park boundaries one finds the highest point in the lower 48 states, Mt. Whitney and the other alpine peaks of the Whitney Crest, the deep trough of the upper Kern River, and the high peaks of the Great Western Divide. Exposures of the granitic rocks of the Sierra Nevada Batholith dominate the park, but numerous roof pendants are scattered across the park providing evidence of events in the early Mesozoic and Paleozoic time. Some of the pendants contain marble, which has weathered to form numerous caverns in the Sierra Foothills. One of these, Crystal Cave, is open for conducted tours.

Kings Canyon preserves the upper reaches of, well, Kings Canyon, which has the distinction of being considerably deeper than the Grand Canyon. At one point just outside the park, the gorge is over 8,000 feet deep (see the top photo). The eastern boundary of the park includes the Palisades Crest, with several peaks exceeding 14,000 feet in elevation. As with Sequoia, much of the park is dominated by batholithic intrusions, but a huge metamorphic roof pendant is traversed by highway 180 on the way to Cedar Grove in the heart of the park (see the second picture). Boyden Cave lies just west of the park entrance, and offers guided tours. Lilburn cave, in the Grant Grove/Redwood Canyon area, has more than 20 miles of mapped passageways, making it one of the longer cavern systems in the country. Several unique ice caves can be found in the Mineral King region.

Both parks provide plentiful evidence of Pleistocene ice age glaciations. The southern limit of Sierra glaciations is just south of the Sequoia boundary. Numerous exfoliation domes lie scattered throughout both parks. The summit of Moro Rock is a popular short hike in the Giant Forest area of Sequoia.

The Far West Section guidebook from the 2005 meeting has five field trips that tour the two national parks and surrounding countryside, and also includes a unique fossil-hunting expedition in the Kettleman Hills on the west side of the Central Valley (bottom photo). The Kettleman Hills are an actively growing anticline composed of Plio-Pleistocene marine sediments, and are an important oil drilling region. The specific chapters include:
  • A Teacher's Guide to the Kaweah River Canyon, Sierra Roof Pendants, and Crystal Cave by Mike Martin and Richard Goode
  • A Teacher's Guide to the Tule River Basin, Dome Rock, and California Hot Springs, by Mike Martin and Richard Goode
  • A Teacher's Guide to the Roadside Geology of Kings Canyon National Park and Giant Sequoia National Monument by Garry Hayes
  • A Teacher's Guide to the Fusegates at Terminus Dam and Kaweah Reservoir by Mike Martin and Richard Goode
  • A Teacher's Guide to Fossil Collecting along Interstate 5 in the Kettleman Hills Area, by Mike Martin and Richard Goode

Sales of the guidebook "A Teacher's Guidebook to the Southern Sierra: Sequoia and Kings Canyon National Park, the Great Western Divide, and the Sierra Nevada Foothills" support the Far West Section scholarships for earth science students,


  1. Can you tell us more about the folds in the second image? They're beautiful!

  2. From the guidebook (which is directed more towards teachers than structural geologists): "A spectacular outcrop on the north side exposes calc-silicate phyllite that is part of the Boyden Cave roof pendant (see Moore, 2000, for an extended discussion). These rocks probably originated as sandy or limey shale on an ocean floor, perhaps adjacent to a continental margin. They have since been heated and folded multiple times. The sharply pointed bends in the rock are called chevron folds."

    The outcrop is 0.6 miles east of the Boyden Cave parking lot, and with an eastern exposure is best viewed in the morning hours.

    Moore, J.G., 2000, Exploring the Highest Sierra, Stanford University Press, Stanford, California, 427 pages (an absolutely essential guide if you go to Sequoia or Kings Canyon)