Geology Of Lake TahoeGEO 103

PROF. MARK LAWLER

BY SAUL J IMENEZ

Introduction - Lake Tahoe was formed from faulting

- About 24 million years ago the Sierra Nevada block was formed by uplifting

- Two principal faults evolved and uplifted blocks created the Carson Range on the east and the Sierra Nevada on the west

- Highest peaks of the Lake Tahoe Basin that formed during this process were Freel Peak at 10,891 ft , Monument Peak at 10,067 ft (present day Heavenly Valley Ski Area), Pyramid Peak at 9,983 ft and Mt. Tallac at 9,735 ft

- General John C. Fremont's discovered the lake in 1844

Lake Tahoe - Present - Modern Lake Tahoe was shaped and landscaped by the

scouring glaciers during the Ice Age a million or more years ago

- Many streams flow into Lake Tahoe, but the lake is drained only by the Truckee River, which flows northeast through Reno and into Pyramid Lake in Nevada

- Lake Tahoe is the third deepest lake in North America and the tenth deepest in the world

- The lake is 22 miles in length and 12 miles wide with approximately 72 miles of shoreline

- Its greatest measured depth is 1,645 feet

- The average depth of the lake is 1,000 feet

- Major recreational activities within the basin include casino gaming in Nevada, alpine and cross-country skiing, golfing, water sports, hiking, fishing, camping, and bicycling

Jeffrey Pine (Pinus jeffreyi) - Most common tree found in the Tahoe basin

- Mainly found in California, but also in the westernmost part of Nevada, southwestern Oregon, and northern Baja California

- It’s a large coniferous evergreen tree with a massive trunk

- The bark is generally reddish brown with narrow plates between deep fissures

- It can live up to 500 years

- It can grow to a height of 180 feet with trunks of up to 7 feet in diameter

- It is named in honor of its botanist documenter John Jeffrey

Steller’s Jay (Cyanocitta stelleri) - Native to western North America

- Steller’s Jays are large songbirds with large heads, chunky bodies, rounded wings, and a long, full tail

- They are intelligent, inquisitive and noisy

- They are mainly found in evergreen forests of western North America, at elevations of 3,000-10,000 feet (lower along the Pacific coast)

- These birds are often seen in campgrounds, picnic areas, parks, and backyards

- They are omnivores and their diet consists of seeds, nuts, berries, and fruits

- Animal-matter portion of food consists of bird eggs and nestlings, invertebrates, suet, small rodents, reptiles, and carrion

Steller’s Jay More Facts

Where these birds are found year-round

- Migration occurs in the Fall and Spring

- Have expanded into a wider variety of habitats within the past 20 years and are now more common in towns and cities than they previously were

- Adults are quiet and secretive while nesting, but become noisy and aggressive if nest is threatened

Coyote - These animals are found a lot in Tahoe

- Its ancestors came from the gray wolf, 1-2 million years ago

- Coyote males average from 18–44 lbs. and females average 15–40 lbs.

- Theory suggests that the coyote evolved in North America during the Pleistocene epoch 1.81 million years ago

- The coyote mates between February and April

- A female will pick a mate they will normally mate for life

- Two months after mating, the female gives birth to on average 6 pups

The pups are weaned when they are about a month old

- They can almost eat anything, they like to hunt rabbits, rodents, fish, frogs, and even deer

- They like eating insects, snakes, fruit, grass, and carrion

Igneous - Pumice - A volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals

- Pumice is a type of extrusive volcanic rock, produced when lava with a very high content of water and gases

- The only rock that floats on water

- Used to make lightweight construction materials such as concrete block and concrete

Metamorphic - Gneiss - A common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally igneous or sedimentary rocks

- The color of the rock is variable generally alternating lighter and darker sub-parallel discontinuous bands

- Hard rock with medium grain size and can see crystals

- Gneiss is a product of regional metamorphism

- This is a type of metamorphism which is associated with mountain building

Igneous - Basalt - Very common igneous rock

- Rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon

- It is most commonly crushed for use as an aggregate in construction projects

- Basalt is usually black or dark gray

- It is composed of mineral grains which are mostly indistinguishable to the naked eye

Mineral - Magnetite - One of the three common naturally occurring iron oxides (chemical formula Fe3O4)

- Magnetite is the most magnetic of all the naturally occurring minerals on Earth

- Magnetite is sometimes found in large quantities in beach sand and found in California and the west of New Zealand

- Magnetite is best known for its property that it is strongly attracted to magnets

Metamorphic - Marble - Non-foliated metamorphic rock composed of recrystallized carbonate minerals

- It is used for sculptures and for building

- Marble is usually a light-colored rock

- Marble of extremely high purity with a bright white color

- Being composed of calcium carbonate, marble will react in contact with many acids, neutralizing the acid

References (n.d.). Retrieved June 21, 2015, from https://en.wikipedia.org/?title=Marble

(n.d.). Retrieved June 19, 2015, from https://en.wikipedia.org/wiki/Jeffrey_pine

(n.d.). Retrieved June 20, 2015, from https://en.wikipedia.org/wiki/Steller's_jay

(n.d.). Retrieved June 20, 2015, from https://en.wikipedia.org/?title=Coyote

(n.d.). Retrieved June 21, 2015, from https://en.wikipedia.org/?title=Pumice

(n.d.). Retrieved June 21, 2015, from https://en.wikipedia.org/wiki/Magnetite

(n.d.). Retrieved June 21, 2015, from https://en.wikipedia.org/?title=Gneiss

About Jeffrey Pines. (n.d.). Retrieved June 19, 2015, from https://www.giant-sequoia.com/about-sequoia-trees/about-jeffrey-pines/

Basalt. (n.d.). Retrieved June 21, 2015, from http://www.sandatlas.org/basalt/

References Cont. Coyotes. (n.d.). Retrieved June 20, 2015, from http://www.allthingstahoe.com/coyotye1.html

Coyotes, Coyote Pictures, Coyote Facts - National Geographic. (n.d.). Retrieved June 20, 2015, from http://animals.nationalgeographic.com/animals/mammals/coyote/

Facts About Lake Tahoe. (n.d.). Retrieved June 19, 2015, from http://tahoe.usgs.gov/facts.html

Geography & History Overview. (n.d.). Retrieved June 19, 2015, from http://tahoe.usgs.gov/geography.html

Gneiss - Metamorphic rocks. (n.d.). Retrieved June 21, 2015, from http://www.sandatlas.org/gneiss/

LAKE TAHOE INFO and FACTS: Lake Tahoe Basin Geology. (n.d.). Retrieved June 19, 2015, from http://www.tahoecam.com/tahoefacts.html

Lake Tahoe Basin Mgt Unit - Learning Center. (n.d.). Retrieved June 19, 2015, from http://www.fs.usda.gov/detail/ltbmu/learning/?cid=stelprdb5109570

Marble. (n.d.). Retrieved June 21, 2015, from http://geology.com/rocks/marble.shtml

References Cont. Pumice. (n.d.). Retrieved June 21, 2015, from https://www.mineralseducationcoalition.org/minerals/pumice

Steller's Jay. (n.d.). Retrieved June 20, 2015, from http://www.allaboutbirds.org/guide/Stellers_Jay/id

Steller's Jay. (n.d.). Retrieved June 20, 2015, from http://birdweb.org/Birdweb/bird/stellers_jay

Steller's Jay. (2014, November 13). Retrieved June 20, 2015, from http://www.audubon.org/field-guide/bird/stellers-jay

Trees of Lake Tahoe - The Pines. (2009, March 28). Retrieved June 19, 2015, from https://beetlesinthebush.wordpress.com/2009/03/28/trees-of-lake-tahoe-the-pines/