Fallen Leaf GeologicalBackground• Similar ecosystem to therest of the basin• Formed during thePleistocene glaciation• Glaciers left behindpolished granite rocks• The Fallen Leaf moraineswere formed by the largeTahoe glacial episode,70,000 to 150,000 yearsago•Watersheld covers an area of about42 square km• Trees consist of common Jeffrey,Ponderosa and Lodgepole pines, alsosome non native quaking aspens inthe area
Geological FeaturesTerminal Moraine-accumulation of ridge-like rock debris, pushedforward by glacial activityLateral Moraine- debrisderived by erosion andavalanche from thevalley wall onto the edgeof a glacier anddepositing as anelongated ridgeMedial Moraine- formed bytwo glaciers from the eastand west
Geological Features• Fallen leaf Moraines– Angora and Cathedral ridge• Medial moraines– Strip of land between LakeTahoe and Fallen Leaf• Two terminal moraines– North end of lake is shallow andsouth end marks the terminalmoraines with a sharp drop off– Two moraines suggests the glacierretreated more than once
Snow Plant HistorySarcodes sanguinea• Occurs through out SierraNevadas, Southern Oregon,Western Nevada andNorthern Mexico• Non-photosynthetic andreceives all nutrients fromfungal root symbionts• Receives all carbon from firhost tree through mycorrhizal• Suggests algal ancestorwith similar symbiotic,mineral absorbing fungus
Mallard HistoryAnas playtrhincos• Ancestors to wildducks thought tohave appearedduring the time of thedinosaurs– Pliocene or earlyPleistocene epoch– About 2 mya, inpresent day Siberia
Mallard HistoryAnas playtrhincos• Ancestors to alldomesticatedducks– Hybridize with about45 other species ofducks and arethought to destroy themallard speciescompletely ifcontinued
Metamorphic Rock• Marposa Slate– Fine grained, foliated metamorphic rock– Formed when pre-existing rocks aresubject to extreme heat and/or pressure– Composed of clay minerals or micas
Metamorphic Rock• Formation of Slate– Created in formally sedimentary basin thatbecomes involved in a convergentboundary– Forces and heat modify clay minerals– Foliation develops at right angles to thecompressive forces to yield verticalfoliation
Igneous Rock• Quartz Monzonite Granite– Dominant igneous rockfound in the basin– Light colored, granular andcourse-grained• Made up of quartz,plagioclase feldspar,potassium feldspar– Lesser amounts of biotite,hornblend and othermineralsGranite formationsnearby at AngoraLake
Bibliography"Rocks of the Sierra Nevada." Geology of the Sierra Nevada.Geologic Trips, n.d. Web. 20 June 2013.<http://www.geologictrips.com/sn/sntro.pdf>.King, Hobart. "Slate." Metamorphic Rock. Geology.com, n.d. Web. 20 June2013. <http://geology.com/rocks/slate.shtml>.Alden, Andrew. "Granite." Granite and Its Geology. About.com Geology,n.d. Web. 20 June 2013.<http://geology.about.com/od/rocks/ig/igrockindex/rocpicgranite.htm>
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