Geology of Lake Tahoe By Jennifer Kline Satellite Pictures, NASALake Tahoe Community College 2012 ResearchPresentation,Geology 103
Table of Content○ Observations○ Lake Tahoe Basin Formation○ Lake Tahoe Faults○ Rocks found in Lake Tahoe Basin○ Fauna of the Lake Tahoe Basin○ Crawfish Fossil Records○ Lake Tahoes Ecosystem○ Flora of the Lake Tahoe Basin○ References
ObservationJuly 2012 I hiked to Granite Lake inDesolation Wilderness on the South endof the Lake Tahoe Basin.I observed many types of birds including,Bald Eagle, Woodpeckers,Styler Jays,Robins, and a Humming Bird.I also saw a freshwater crawfish and amarmot.
Lake Tahoe Basin Formation Sierra Nevadas○ Basin was under a shallow sea on Pangea○ North American Continental Plate broke off from Pangea (210 mya)○ Pacific Ocean Plate drifted east○ Pacific Plate was pushed under North America Plate.○ during the next 130 million years plate tectonic pressure and magma chamber caused uplift creating the Sierra Nevada Mountain Range
Lake Tahoe Basin Formation(continued)○ uplifting formed parallel faults○ Sierra Crest rose in the west○ Carson Range dropped in the east○ lava flow dammed the Carson Valley and the Basin was formed○ glaciers carved and polished rock○ snow run off eventually filled Lake Tahoe(Investigating The Sierra NevadaMountains and Lake Tahoe, (NASA)
Lake Tahoe Major FaultsNorthern portion ofTahoe is tectonicallyactive with three majorfaults: ● Incline Fault ● Stateline Fault ● West Tahoe Fault Picture (Sacramento Bee, 2006)
Rocks found in Lake Tahoe Basin Igneous intrusive rocks (typically granodiorite) and igneous extrusive rocks (typically andesitic lahar). Small amounts of metamorphic rock occur in the Spooner Summit and Desolation Wilderness areas (NRCS 2007).
Rocks found in Lake Tahoe BasinGranite formed from increased pressureand temperature from the colliding platescaused rock to melt then the coolingprocess allowed crystals to form and createthe granitic rock seen in the Sierra Nevada. Granite forms in plutonic environments and contains potassium feldspar, plagioclase feldspar, quartz, biotite and/or amphibole Granite Igneous rock with coarse grain classification acid
Rocks found in Lake Tahoe BasinMetamorphic rock forms when heat, pressureand/or chemical activity transform rock suchas sedimentary or igneous rock.Metamorphicrock is much harder than the originalsedimentary rock and can still be seen todayin many areas as caps on top of the Sierragranitic rock. Metamorphic Rock Metamorphic rock is an igneous rock containing minerals such as olivines, pyroxenes, amphiboles, micas,feldspars and quartz.
Fauna of Lake Tahoe BasinCrayfish,(also called crawfish orcrawdads)were introduced into theLake Tahoe Basins ecosystem inthe 1960s○ members of Astacidae and Parastacidae families○ freshwater crustaceans○ evolved from Decapoda order○ lives in freshwater shallows in Lake Tahoe, surrounding rivers and streams○ feeds on aquatic plants and animal life
Crawfish Fossil Records○ Crawfish evolve from the Decapoda order○ oldest fossil record are the Albian fossils found in Victoria, AustraliaScientific classificationKingdom: AnimaliaPhylum: ArthropodaSubphylum: CrustaceaClass: MalacostracaOrder: DecapodaInfraorder:AstacideaSuperfamily: ParastacoideaFamily: Parastacidae(Rodney A. Feldmann, Carrie E. Schweitzer & John Leahy 2011)
Lake Tahoe Basin Ecosystems Elements of Tahoes Ecosystem○ soil ○ trees○ incects ○ water○ wildlife ○ people○ plants All elements must find a way to coexist in the same environment to keep Lake Tahoes Ecosystem health.
Flora of Lake Tahoe BasinLupinus perennis grows all over the basin and flowers in thespring blooms lasting into the summer. There are about 280species of this genus.Kingdom: Plantae Order: FabalesFamily: Fabales Subfamily: FaboideseTribe: Genisteae Genus: Lupinus
ReferenceWEBSITE:Lake Tahoe, From Wikipedia, the free encyclopedia, last update 2012http://en.wikipedia.org/wiki/Lake_Tahoe#GeologyNASA Investigating The Sierra Nevada Mountains and Lake Tahoe, 2012https://earthkam.ucsd.edu/ek-images/investigating_images/lake_tahoeU.S.Geological Survey, Lake Tahoe, 2004http://tahoe.usgs.gov/pictures.htmlThe Sacramento Bee, Lake Tahoe Fault Could Deliver MassiveEarthquake, 2006http://www.standeyo.com/NEWS/06_Earth_Changes/061226.Lake.Tahoe.Fault.htmlUnited States Department of Agriculture, Forest Service, Lake TahoeBasin Management Unit, 2012United States Department of Agriculture, Natural Resources ConservationServices, 2007Rodney A. Feldmann, Carrie E. Schweitzer & John Leahy (2011). "NewEocene crayfish from the McAbee Beds in British Columbia: First record ofParastacoidea in the Northern Hemisphere