Geology of Lake TahoeNicole HamiltonGeology 103Field Assignment
Formation of Tahoe• Around 24 million yearsago the Sierra Nevadaformed by faulting.• Lava from Mt. Plutoformed a dam whichwater from snowmeltand stream made alarger lake than today’s.• Migrating glaciersformed V-shapedcanyons into U-shapedvalleys (Geology of theLake Tahoe Basin, n.d.).
The Lake of Tahoe• Lake Tahoe is the thirddeepest lake in NorthAmerica, tenth in theworld.• Twenty-two miles longand twelve miles wide.• Greatest measureddepth is 1,645 feet.• Fun fact: The bottom ofthe lake is at a lowerelevation than CarsonCity, Nevada (Geology ofLake Tahoe Basin, n.d.).
Igneous-Rhyolite• I believe this rock tobe Rhyolite.• Rhyolite is avolcanic rockcomposed mostly offelsic.• It’s said to havesome resemblanceto granite.• It forms at lowtemperatures with ahigh percentage ofsilica (Nave, n.d.).
Igneous-Granite• I believe this rock to beGranite.• Granite is a course rockwith large amounts offeldspar and quartz.• Granite is also the mostabundant rock in thecontinental crust.• It forms when magma’scrystallization is slowbeneath the surface(Granite, n.d.).
RaccoonProcyon lotor• Raccoons can be found allover the United Statesexcept for Central Nevada,Rocky Mountains, Utah,and Arizona.• Omnivorous• Mostly nocturnal• Easily identifiable by theirblack mask and ringed tail(Raccoon, 2013).• Raccoons are part of theCarnivora order andProcyonidae family(Raccoon, wiki).
Raccoon Evolution• Animalia => Chordata => Mammalia => Carnivora =>Procyonidae => Procyon => P. lotor• Carnivora evolved from Miacidae around the middle and lateEocene, from both North America and Eurasia (Carnivora,wiki).• The first known members Procyonidae lived in Europe in thelate Oligocene about 25 million years ago.• The common ancestor of the raccoon is said to have lefttropical areas around 2.5 million years ago (Raccoon, wiki).
Black BearUrsus americanus• American Black Bears arepart of the order Carnivoraand a part of the Ursidaefamily (American BlackBear, wiki).• They range from Alaska toCanada, and down toMexico.• Black Bears are omnivores,eating both meat andplants it finds in the forest.• They can run up to 30miles per hour, and arecrepuscular (AmericanBlack Bear, n.d.).
Black Bear Evolution• Animalia => Chordata => Mammalia => Carnivora => Ursidae=> Ursus => U. americanus• Ursus abstrusus is the oldest known North American fossilmember of Ursus from nearly 5 million years ago.• The earliest American black bear fossils were found in PortKennedy, Pennsylvania.• A wider variety of foods helped the American black bearsurvive the ice age 10,000 years ago (American black bear,wiki).
Snow FlowerSarcodes sanguinea• Snow flowers are parasiticof fungus living under theground or wet soil.• They appear after thesnow melts or has mostlymelted.• It ranges from California towestern Nevada.• The stamen inside thepetals collect pollen, whichit later shakes out ordevelops fruit inside of it(Sarcodes sanguinea, n.d.).• Snow flowers are part ofthe order Ericales and thefamily of Ericacaea(Sarcodes, wiki).
Snow Flower Evolution• Plantae => Angiosperms => Eudicots => Asterids => Ericales =>Ericaceae => Sarcodes => S. sanguinea• The earliest angiosperm macrofossil is dated to 125 millionyears ago (Angiosperm, wiki).• Ericacaea have a wide range, including Antartica, Greenland,Australia, and the Americas (Ericacaea, wiki).• S. Sanguinea is found in most of California and westernNevada (Sarcodes, wiki).
ReferencesGeology of the Lake Tahoe Basin. (n.d.). In Lake Tahoe Basin Mgt Unit - Learning Center.Retrieved June 18, 2013, fromhttp://www.fs.usda.gov/detail/ltbmu/learning/?cid=stelprdb5109570Raccoon. (2013). In Nature Works. Retrieved June 19, 2013, fromhttp://www.nhptv.org/natureworks/raccoon.htmRaccoon. (n.d.). In Wikipedia. Retrieved June 18, 2013, fromhttp://en.wikipedia.org/wiki/RaccoonAmerican Black Bear. (n.d.). In Wikipedia. Retrieved June 20, 2013, fromhttp://en.wikipedia.org/wiki/American_black_bearAmerican Black Bear. (n.d.). In Nature Works. Retrieved June 19, 2013, fromhttp://www.nhptv.org/natureworks/blackbear.htmSarcodes sanguinea. (n.d.). In Botanical Society of America. Retrieved June 20, 2013, fromhttp://www.botany.org/parasitic_plants/Sarcodes_sanguinea.php
Sarcodes. (n.d.). In Wikipedia. Retrieved June 20, 2013, fromhttp://en.wikipedia.org/wiki/SarcodesNave, R. (n.d.). Rhyolite. Retrieved June 18, 2013, fromhttp://hyperphysics.phy-astr.gsu.edu/hbase/geophys/rhyolite.htmlGranite. (n.d.). In Geology.com. Retrieved June 18, 2013, fromhttp://geology.com/rocks/granite.shtmlCarnivora. (n.d.). In Wikipedia. Retrieved June 21, 2013, fromhttp://en.wikipedia.org/wiki/CarnivoraAngiosperms. (n.d.). In Wikipedia. Retrieved June 21, 2013, fromhttp://en.wikipedia.org/wiki/AngiospermsEricaceae. (n.d.). In Wikipedia. Retrieved June 21, 2013, fromhttp://en.wikipedia.org/wiki/Ericaceae