The Tahoe Basin of the Sierra Nevada Range

Professor Mark LawlerGEO 103 Summer ’11

Sam Dunn

Lake Tahoe History: How the Lake Was Formed

Approximately two to three mya, a normal fault created the Carson Range to the east and the Sierra Nevada to the west.

In between these two ranges, the subsequent “drop down blocks” resulted in the creation of the 1,600 feet deep Lake Tahoe Basin.

Lake Tahoe is a “geologic block faulting" type of lake.

Lake Tahoe Rocks: A Stunning Present Wroughtfrom a Violent Past

When the Sierra Nevada range began its uplift, the igneous rock granite that had formed deep underground surfaced through erosion and glacial activities and was then shaped into smooth cliffs and mountains.

Lake Tahoe Rocks: A Stunning Present Wroughtfrom a Violent Past

Much of land that surrounds the lake is typically very dry.

The decaying granite creates a very dry ground atmosphere, making it necessary to water plants and grass very often.

The decaying granite that surrounds the lake is feared to be creating radon gas.

Lake Tahoe Rocks: A Stunning Present Wroughtfrom a Violent Past

Mostly eroded and scattered about the entire Sierra Nevada range, there is evidence of igneous volcanic rock, complete with xenoliths as it settled, mostly in and around Round Lake, near Lake Tahoe outside of the Carson Valley, denoting very active volcanic activity ~20 mya.

Lake Tahoe Fauna: A Tenuous Co-existence

Native to California, the raccoon is known to live in forests and more remote mountainous areas. Either encroaching on humans, or the other way around, this adorable-but-mean creature can be found in more and more towns. A natural omnivore, The raccoon has evolved into a fearless night-time garbage scavenger.

Lake Tahoe Fauna: A Tenuous Co-existence

Found all throughout the western US, the deep-blue and boisterous Stellar’s Blue Jay is an omnivore “resident” song bird who nests in the abundant conifer trees of Lake Tahoe.

Similar to the area’s scavenging raccoon, the Stellar’s Blue Jay has also become dependent on humans; they rely on birdfeeders and garbage to supplement their natural conifer seed diet.

Lake Tahoe Flora: Short, Wet Springs Yield Color

The beautiful blue Cat Mint flowering blue shrubs thrive all summer in high altitudes where there is abundant sun and well-draining soil.

Cat Mint is hearty succulent flowering bush, often growing in clumps with other yellow California “deer resistant” yellow wildflowers along bike paths in Lake Tahoe.

Lake Tahoe Flora: Thriving Marshland

The Truckee River was once a massive river that was then diverted by volcanic activity that connected Two ranges (Carson and Crystal), creating an outlet for the river in the northwest corner of the basin.

Lake Tahoe Flora: Thriving Marshland

The Truckee river flows near Lake Tahoe and has formed marshlands where Marsh Willows thrive in extreme temperatures, protecting the lakebeds from erosion. The alkaline soil and abundant summer sun creates a perfect ecosystem for growth and airborne asexual reproduction.

References

Facts about Lake Tahoe (2008). In Facts about Lake Tahoe. Retrieved July 19, 2011, from http://tahoe.usgs.gov/facts.html

Part II: Age of Fire. (2000). In Lake Tahoe Facts, Natural History & Human History. Retrieved July 19, 2011, from http://www.tahoeadventuresports.com/misc/tahoefacts.htm

Seattle Audubon Society. (2005-2008). General Description. In Steller's Jay - BirdWeb. Retrieved July 18, 2011, from http://www.birdweb.org/birdweb/bird_details.aspx?id=310

Where Do Raccoons Live?. (1986). In Raccoon (Procyon lotor). Retrieved July 19, 2011, from http://pelotes.jea.com/AnimalFact/Mammal/raccoon.htm

Wierbinski, A. (n.d.). Hard, Fine Grain Volcanic Rock Fragment. In Backpacking past Round Lake to Meiss Cabin. Retrieved July 19, 2011, from Hard, Fine Grain Volcanic Rock Fragment

Wisconsin Dept. of Natural Resources. (2004, September 3). Willow (Salix spp.). In Invasive Species-Willow (Salix spp) - WDNR. Retrieved July 19, 2011, from http://dnr.wi.gov/invasives/fact/wetshrubs_willow.htm

You Can Learn Series. (2004-2008). Catmint, Blue Flowers Last All Summer. In Catmint. Retrieved July 17, 2011, from http://www.youcanlearnseries.com/Landscape/Plants/Catmint.aspx