Emerald BayExquisite cell phone photography by Author

Geology 103 – Prof LawlerIggy Strbac

I decided to carryout my research assignment in Emerald Bay largely because it gave me an opportunity to go jet skiing for science. In 1969 it was designated a National

Natural Landmark for its brilliant panorama of mountain building processes and glacier carved granite.

I did not use my cell phone for this one

Brief Geology• The grandeur of the parks and their setting came from

successive upheavals of the mountain-building processes that raised the Sierra Nevada. (Everytrail)

• Long after Lake Tahoe formed, huge glaciers in the Northern Sierra Nevada created a number of lakes surrounding Lake Tahoe. Sliding down V-shaped canyons on Lake Tahoe’s western side, the glaciers scoured away rock and created broad U-shaped valleys. (Geocaching)

• Once these valleys filled with snowmelt water, the resulting elongated depressions are now known as Fallen Leaf Lake, Emerald Bay, and Cascade Lake. (Geocaching)

• Geologists believe that the Fannette Island granite resisted the glacial ice. (Everytrail)

• There were two major glaciations in this area - the Tahoe and the Tiogan. When these two glacier systems were flowing, they were doing so from about 9900 feet above sea level. Now that is a lot of ice! (Geocaching)

• The mountains were carved by glaciers as evidenced by the U-shaped valley and deposited till around 1 million years ago during the Cenozoic Era. (Quake)

Brief Geology

GeologicalMap Key

Geological Map of Emerald BayThis comprehensive diagram I edited was made by George J. Saucedo for the Californian Geological Survey in 2005

Granite (Possibly Late and Middle Jurassic)

• Granite is an intrusive igneous rock meaning it was formed from magma and is the most common type of plutonic rock. • Granite is composed mainly of quartz and feldspar with minor amounts of mica, amphiboles and other minerals. (H. King) • Gradations from granite to anorthosite originate by inclusion and reaction. (F.F. Grout and W.W. Longley)• At the surface granite is exposed in the cores of many mountain ranges, within large areas known as batholiths, and in the core areas of continents known as shields. (H. King) • I determined this cliff was comprised of granite by noting its blatantly visible feldspars and comparing its location to the geological map via Californias Geological Survey, Regional Geologic Map No. 4 (Quake)

I did not use my cell phone for this one either

Granodiorite • Granodiorite or is an intrusive igneous rock similar to granite, but containing more plagioclase than orthoclase-type feldspar. (Wikipedia)• It usually contains abundant biotite mica and hornblende, giving it a darker appearance than true granite. (About)• I determined these rocks are comprised of granodiorite by noting its appearance and weathered exterior and comparing its location to the geological map via Californias Geological Survey, Regional Geologic Map No. 4 (Quake)

Basalt• Basalt is a common extrusive igneous

rock formed from the rapid cooling of basaltic lava exposed at or very near the surface (H. King)

• Basalt is usually grey to black in color.• Basalt with a vesicular texture, as seen

here, is called scoria and forms when dissolved gases are forced out of solution as the lava decompresses and reaches the surface. (Wikipedia)

• Basalt underlies more of Earth's surface than any other rock type.

• Basaltic volcanism in Tahoe occurred in two major pulses: 2.3 - 2.0 Ma and 0.92 Ma (W. T. Kortemeier, et. al)

• The color and vesicular texture leads me to believe this is rock is a type of basalt.

Canadian GooseLatin:  Branta canadensisAverage length: Male 25-45 inchesAverage weight: Male 3-13 lbs, Female 3-11 lbs

• The birds find refuge in Tahoe when they molt their feathers in the spring and can't fly. (Tahoe Daily Tribune) • The first well documented Canadian Goose encounter in Lake Tahoe occurred June 1st, 1909. (Milton S. Ray)• The Canada goose is a species of goose that is specific to North America. They have evolved to thrive in the fluctuating temperatures of bitter cold to sweltering heat of the United States and Canada. (Wildlife Removal) • The Canada Goose has grown particularly fond of Tahoe urban environments because the waterways are maintained and clean and there is always a group of tourists wanting to throw food at them. (Wildlife Removal)

Human• Latin:  Homo Sapien 

Avg. height: 4’7” (1.4m) to 6’3” (1.9m)Avg. weight: Male 168-183 lbs, Female 120-140 lbs

• Temporal range: Pleistocene - Present• The functional portion of human DNA is

approximately 98.4% identical to that of chimpanzees when comparing single nucleotide polymorphisms thus the closest living relatives of humans are gorillas and chimpanzees, as they share a relatively recent common ancestor. (Wood, B)

• Anatomically modern humans first appear in the fossil record in Africa about 195,000 years ago, and studies of molecular biology give evidence that the approximate time of divergence from the common ancestor of all modern human populations was 200,000 years ago.

• Here, we see a native Tahoe local enjoying a soda while perched on the tea castle on Fanette Island.

Ponderosa Pine•Latin:  Pinus ponderosaMax height: 265’ or 81mAverage needle length: 6-12” or 15–30 cm

• Mature individuals have cinnamon-red bark with black crevices. Younger trees have black to reddish-brown bark.• Not as common in the Tahoe Basin because it prefers somewhat lower elevations than the Jeffrey pine. (Ted C. MacRae)• Ponderosa pine generally evolved with a natural cycle of frequent, low-intensity fire, which eliminated competing conifer seedlings but allowed mature pines to survive. (CSFS)• A long taproot helps the drought-resistant pine obtain adequate moisture and also decreases its chances of being uprooted by strong winds. (CSFS)• I determined this was a Ponderosa pine instead of a Jeffrey pine due to its darker red shade and prickly cones scattered around its base.

Refrences

Associated Press. (2006, June 6). Study: Geese are major tahoe polluters. Retrieved from http://www.tahoedailytribune.com/article/20060619/NEWS/60619003

Canada goose. (2013, June 23). Retrieved from https://en.wikipedia.org/wiki/Canada_Goose Canada goose removal and control. (n.d.). Retrieved from http://www.wildlife-removal.com/canadagoose.html Emerald Bay. (n.d.) Retrieved from

http://www.geocaching.com/seek/cache_details.aspx?guid=509ab4c1-60ef-4788-a559-fea9333b8c98 Emerald bay state park. (n.d.). Retrieved from http://www.everytrail.com/destination/emerald-bay- state-park Frank F. Grout and W. W. Longley. The Journal of Geology. Vol. 43, No. 2 (Feb. - Mar., 1935), pp. 133-141

Published by: The University of Chicago Press Fun facts & history. (2013). Retrieved from http://keeptahoeblue.org/abouttahoe/history-facts/ Kortemeier, W. T., Moore, J. G., Schweikert, R. A., & Calvert, A. T. (2009, December). Ar-ar ages of lake tahoe

basalts confirm several eruptions at 2.3 to 2.0 ma and establish 0.92 ma activity. Retrieved from http://adsabs.harvard.edu/abs/2009AGUFM.V41B2177K

Refrences

MacRae, T. (2009, March 28). [Web log message]. Retrieved from http://beetlesinthebush.wordpress.com/2009/03/28/trees-of-lake-tahoe-the-pines/

Milton S. Ray. The Condor , Vol. 14, No. 2 (Mar. - Apr., 1912), pp. 67-72Published by: University of California Press on behalf of the Cooper Ornithological SocietyArticle URL: http://www.jstor.org/stable/1361812

Ponderosa pine. (n.d.). Retrieved from http://csfs.colostate.edu/pages/forest-types-ponderosa-pine.html Saucedo, G. (2007). Geological map of the lake tahoe basin. Retrieved from

http://www.quake.ca.gov/gmaps/RGM/tahoe/tahoe.html

University Of Utah (2005, February 28). The Oldest Homo Sapiens: Fossils Push Human Emergence Back To 195,000 Years Ago.

Wood B, Richmond BG (July 2000). "Human evolution: taxonomy and paleobiology". J. Anat. 197: 19–60