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TRANSCRIPT
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Emerald Bay, Eagle Falls and
the Sierra Nevada
Field Assignment Professor Lawler- Geology
103By Kalie Ceglia
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Contents:
• Geologic Evolution of Tahoe Basin and the Sierra Nevada• Rock Samples
• Quartz• Agate• Granite
• Plant Sample- ‘snow plant’• References
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Geologic evolution of Lake Tahoe Basin (started 400 million years ago) • Lake Tahoe was formed by faulting • 3 faults make up the Tahoe Basin- West Tahoe Fault ( Sierra Nevada), East Tahoe Fault ( Carson Range),
and the North Tahoe Fault• ‘Dropped down blocks ‘ formed the Basin in between• Soils include:- Andesitic volcanic rocks- Granodiorite- Metamorphic rock
Tahoefacts.com, 2013
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T. Macrae, 2009
• The weight of the glaciers cause it to move and flow downhill
• This creates U-shaped glacier valleys and V-shaped stream valleys
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The glaciers move through canyons like this one
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Glacier movement through river beds
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More recently:
• About 10MYR ago, the real uplift of the Sierra Nevada happened:
• Volcanic rock, sedimentary rock, and metamorphic rock were carried away to surrounding valleys, as a result there is still geologic evidence in the Tahoe Basin
• As recent as 10,000yr ago, the last parts of the Ice age, glaciation was happening in the Sierra Nevada
• How the Emerald Bay area was formed is an example of a lateral moraine( where sediment is transported, then deposited along the ridges)
Monroe, 357, 2006
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Evidence of Scraping
As the glaciermoves it picks up:• rocks• sediment• boulders
• The boulders androcks scrape alongthe bedrock
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Approx. 6800ft, Near Eagle Falls Trail
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Lake Tahoe and Basin
Features Metric unit English unit
Maximum depth(second deepest in the U.S.)
501 m 1,645 ft
Average depth 305 m 1,000 ftMaximum diameter(north-south)
35 km 22 mi
Minimum diameter(east-west)
19 km 12 mi
Surface area 495 km2 191 mi2
Average surface elevation(above sea level)
1,897 m 6,225 ft
Highest peak (Freel Peak) 3,320 m 10,891 ft
Tahoe.usgs.gov,2013
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Topographical map of Emerald Bay
Americansouthwest.net,2013
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The Glaciers Taking Shape
Glaciers:
• Glaciers are very large bodies of snow and ice combined
• When more snow accumulates than can melt, glaciers are formed
• The snow begins to melt in the day but refreezes at night , this forms the singular sheet of ice
Resendes, 2011
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Tahoebest.com, 2013
Lower Eagle FallsLocation: South Lake Tahoe, Lake Tahoe Basin, El Dorado CountyStream: Eagle CreekAlternate Names:Height: 140 ft. Elevation: 6600 ft. (-350 ft.) Lat/Long:38.95185, -120.11029
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Americansouthwest.net,2013
Topographical of Upper Eagle Falls and Eagle Falls Lake
Location: South Lake Tahoe, Lake Tahoe Basin, Eldorado County Height: ~20 ft. Elevation: 660 ft. Lat/Long: 38.94999N,120.11618W
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Lower Eagle Falls • During the Spring the snow melts rush down from above, come mid-summer, it is only a trickle
• Due to the number of visitors, there is an increasing environmental concern for the Eagle Falls area
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Standing on top of the Lower Eagle Falls
Fannette Island:
This island is made of Granite, which resisted the force of the glacial ice.
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Upper Eagle Falls
Location: South Lake Tahoe, Lake Tahoe Basin, Eldorado County Height: ~20 ft. Elevation: 6650 ft. Lat/Long: 38.94999N, 120.11618W
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UPPER EAGLE FALLS
(TAKEN FROM THE BRIDGE LOOKING DOWNSTREAM)
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Quartz found locally in the Lake Tahoe Basin
Rockshop,2013
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Quartz: mineral
•Form the continental crust•Most commonly clear, white (milky), or rose in color
• It is considered a hard and stable mineral• In metamorphic rock, it can become veineous and banded in appearance
www.backyardnature.net, 2013
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• Veins of quartz can provide evidence ofhydrothermal activity
Geology.com, 2013
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Agate: Semi-precious silica mineral
• Microcrystalline variety of silica
• Associated with and found around volcanic rocks or where volcanic activity once occurred
• Comes in a variety of shapes and colors
• Appears banded when cut
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More Agate
( This was found in the middle of the trail and was the only other specimen than the picture before during the whole hike)
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GraniteGranite: The Sierra Nevada was volcanically active. Not a surprise to find granite which was at one time magma
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Granite: igneous rock, silicate
• Granular• Intrusive• Varies in color: pink, white, gray, red• Mineral content: biotite, quartz, mica, orthoclase feldspar• Granite is part of the continental crust• It is magma from deep in the crust , cooled down and formed into
rock then pushed up to the Earth’s surface
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SARCODES OR ‘SNOWPLANT’
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Scientific name: Sarcodes sanguineaRank: SpeciesHigher classification: Sarcodes
SarcodesSarcodes is a monotypic genus of a single springtime flowering plant in the heath family containing the single species Sarcodes sanguinea, commonly called the snow plant or snow flower.
Wikipedia, 2013
Found in the Sierra Nevada
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ReferencesBackyard Nature with Jim Conrad. (n.d.). Retrieved from http://www.backyardnature.netEagle Falls Trail Lake Tahoe. (n.d.). Retrieved April 3, 2013, from http://www.tahoesbest.com/eagle-falls-trail-lake-tahoeEmerald Bay SP. (n.d.). Retrieved 2013, from http://www.parks.ca.gov/?page_id=506Facts about Lake Tahoe. (n.d.). Retrieved from http://tahoe.usgs.gov/facts.htmlGoogle Image Result for http://www.aboutlaketahoe.com/hiking/topo-maps/emerald-bay-topo.jpg. (n.d.). Retrieved June 16, 2013, from http://www.google.com/imgres?imgurl=http://www.aboutlaketahoe.com/hiking/topo-maps/emerald-bay-topo.jpg&imgrefurl=http://www.aboutlaketahoe.com/hiking/emerald_bay
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Granite: Igneous Rock - Pictures, Definition & More. (n.d.). Retrieved from http://geology.com/rocks/granite.shtmlGuyton, B. (1998). Glaciers of California: Modern glaciers, ice age glaciers, origin of Yosemite Valley, and a glacier tour in the Sierra Nevada. Berkeley: University of California Press.Hill, M. (1975). Geology of the Sierra Nevada. Berkeley: University of California Press.Lake Tahoe Facts, Natural History, & Human Histroy. (n.d.). Retrieved June from http://www.tahoeadventuresports.com/misc/tahoefacts.htmMacrae, T. (n.d.). Born of glaciers | Beetles In The Bush. Retrieved April 5, 2013, from http://beetlesinthebush.wordpress.com/2009/03/17/born-of-glaciers/
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Monroe, J. S., & Wicander, R. (2006). The changing Earth: Exploring geology and evolution. Belmont, CA: Thomson Brooks/Cole.Resendes (2011). Plate tectonics: Continental drift and mountain building. Berlin: Springer-Verlag.Sarcodes - Wikipedia, the free encyclopedia. (n.d.). Retrieved May 15, 2013, from http://en.wikipedia.org/wiki/SarcodesTopographic Map of the Eagle Falls Trail, Lake Tahoe, California. (n.d.). Retrieved from http://www.americansouthwest.net/california/lake_tahoe/eagle-falls-trail-map.htmlWikipedia, the free encyclopedia. (n.d.). Retrieved June 18, 2013, from http://en.wikipedia.org/