1. Geology of Lake Tahoe
Nicole Hamilton
Geology 103
Field Assignment

2. Formation of Tahoe
• Around 24 million years
ago the Sierra Nevada
formed by faulting.
• Lava from Mt. Pluto
formed a dam which
water from snowmelt
and stream made a
larger lake than today’s.
• Migrating glaciers
formed V-shaped
canyons into U-shaped
valleys (Geology of the
Lake Tahoe Basin, n.d.).

3. The Lake of Tahoe
• Lake Tahoe is the third
deepest lake in North
America, tenth in the
world.
• Twenty-two miles long
and twelve miles wide.
• Greatest measured
depth is 1,645 feet.
• Fun fact: The bottom of
the lake is at a lower
elevation than Carson
City, Nevada (Geology of
Lake Tahoe Basin, n.d.).

4. Igneous-Rhyolite
• I believe this rock to
be Rhyolite.
• Rhyolite is a
volcanic rock
composed mostly of
felsic.
• It’s said to have
some resemblance
to granite.
• It forms at low
temperatures with a
high percentage of
silica (Nave, n.d.).

5. Igneous-Granite
• I believe this rock to be
Granite.
• Granite is a course rock
with large amounts of
feldspar and quartz.
• Granite is also the most
abundant rock in the
continental crust.
• It forms when magma’s
crystallization is slow
beneath the surface
(Granite, n.d.).

6. Raccoon
Procyon lotor
• Raccoons can be found all
over the United States
except for Central Nevada,
Rocky Mountains, Utah,
and Arizona.
• Omnivorous
• Mostly nocturnal
• Easily identifiable by their
black mask and ringed tail
(Raccoon, 2013).
• Raccoons are part of the
Carnivora order and
Procyonidae family
(Raccoon, wiki).

7. Raccoon Evolution
• Animalia => Chordata => Mammalia => Carnivora =>
Procyonidae => Procyon => P. lotor
• Carnivora evolved from Miacidae around the middle and late
Eocene, from both North America and Eurasia (Carnivora,
wiki).
• The first known members Procyonidae lived in Europe in the
late Oligocene about 25 million years ago.
• The common ancestor of the raccoon is said to have left
tropical areas around 2.5 million years ago (Raccoon, wiki).

8. Black Bear
Ursus americanus
• American Black Bears are
part of the order Carnivora
and a part of the Ursidae
family (American Black
Bear, wiki).
• They range from Alaska to
Canada, and down to
Mexico.
• Black Bears are omnivores,
eating both meat and
plants it finds in the forest.
• They can run up to 30
miles per hour, and are
crepuscular (American
Black Bear, n.d.).

9. Black Bear Evolution
• Animalia => Chordata => Mammalia => Carnivora => Ursidae
=> Ursus => U. americanus
• Ursus abstrusus is the oldest known North American fossil
member of Ursus from nearly 5 million years ago.
• The earliest American black bear fossils were found in Port
Kennedy, Pennsylvania.
• A wider variety of foods helped the American black bear
survive the ice age 10,000 years ago (American black bear,
wiki).

10. Snow Flower
Sarcodes sanguinea
• Snow flowers are parasitic
of fungus living under the
ground or wet soil.
• They appear after the
snow melts or has mostly
melted.
• It ranges from California to
western Nevada.
• The stamen inside the
petals collect pollen, which
it later shakes out or
develops fruit inside of it
(Sarcodes sanguinea, n.d.).
• Snow flowers are part of
the order Ericales and the
family of Ericacaea
(Sarcodes, wiki).

11. Snow Flower Evolution
• Plantae => Angiosperms => Eudicots => Asterids => Ericales =>
Ericaceae => Sarcodes => S. sanguinea
• The earliest angiosperm macrofossil is dated to 125 million
years 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 western
Nevada (Sarcodes, wiki).

12. References
Geology of the Lake Tahoe Basin. (n.d.). In Lake Tahoe Basin Mgt Unit - Learning Center.
Retrieved June 18, 2013, from
http://www.fs.usda.gov/detail/ltbmu/learning/?cid=stelprdb5109570
Raccoon. (2013). In Nature Works. Retrieved June 19, 2013, from
http://www.nhptv.org/natureworks/raccoon.htm
Raccoon. (n.d.). In Wikipedia. Retrieved June 18, 2013, from
http://en.wikipedia.org/wiki/Raccoon
American Black Bear. (n.d.). In Wikipedia. Retrieved June 20, 2013, from
http://en.wikipedia.org/wiki/American_black_bear
American Black Bear. (n.d.). In Nature Works. Retrieved June 19, 2013, from
http://www.nhptv.org/natureworks/blackbear.htm
Sarcodes sanguinea. (n.d.). In Botanical Society of America. Retrieved June 20, 2013, from
http://www.botany.org/parasitic_plants/Sarcodes_sanguinea.php

13. Sarcodes. (n.d.). In Wikipedia. Retrieved June 20, 2013, from
http://en.wikipedia.org/wiki/Sarcodes
Nave, R. (n.d.). Rhyolite. Retrieved June 18, 2013, from
http://hyperphysics.phy-astr.gsu.edu/hbase/geophys/rhyolite.html
Granite. (n.d.). In Geology.com. Retrieved June 18, 2013, from
http://geology.com/rocks/granite.shtml
Carnivora. (n.d.). In Wikipedia. Retrieved June 21, 2013, from
http://en.wikipedia.org/wiki/Carnivora
Angiosperms. (n.d.). In Wikipedia. Retrieved June 21, 2013, from
http://en.wikipedia.org/wiki/Angiosperms
Ericaceae. (n.d.). In Wikipedia. Retrieved June 21, 2013, from
http://en.wikipedia.org/wiki/Ericaceae