Lab/Field Assignment Geology 103 Prof Mark Lawler Spring 2013

1. By Amber Westbrook
Lake Tahoe Basin

2. The Formation of Lake Tahoe and
the Basin…
“The Lake Tahoe Basin was formed by geologic block (normal) faulting about
2 to 3 million years ago.”(Facts About Lake Tahoe. (2012, December 13). In USGS. Retrieved June 15, 2013)
“Modern Lake Tahoe was shaped and landscaped by the scouring glaciers
during the Ice Age (the Great Ice Age began a million or more years ago).”
(Facts About Lake Tahoe. (2012, December 13). In USGS. Retrieved June 15, 2013)
These 2 geologic events are what is responsible for the beautiful Lake Tahoe
and the basin that we all love.
This picture is Fallen
Leaf Lake in the Lake
Tahoe Basin

3. More on Lake Tahoe
 Tahoe has some of the most beautiful sunsets in the summer due to
the afternoon clouds that cover the sky!

4. Lake Tahoe Landscape
 I took this picture on the East shore of Lake
Tahoe, as you can see the water’s edge is
surrounded by Igneous rocks, mostly
Granite.
These rocks are here
from volcanic activity
that occurred over on
million years ago!
This picture was taken towards the top
of Echo Summit. The remaining stump is
an old growth Jeffery Pine Tree,
estimated at 500 years old!
Jeffery pines are one of the most
common trees in the Tahoe Area. This
tree provides shelter and food for many
birds and small animals. (Plant Guide. (2006, June
22). In USDA. Retrieved June 15, 2013,)

5. Geology Rocks!
•This is an Igneous lava rock, called the Scoria.
•These are formed when the magma erupts
from a pluton and the lava cools rapidly, within
hours. (Formation, Classification, and Identification of Igneous
Rocks. (2000, September 29). In An Introduction to Igneous Rocks.
Retrieved June 16, 2013)
•When rapid cooling occurs no minerals are
able to form, so the results are Scoria and
obsidian.
I took this picture in the Fallen Leaf
area while hiking.

6. Geology Rocks Again!
oThe picture to the right is also belongs to the
Igneous rock family. It is called Granite.
oThis is the most common rock found here in Lake
Tahoe due to the faulting that occurred here
millions of years ago.
oGranite is formed when magma cools very
slowly, over thousands to millions of years. This
slow process allows the minerals to grow large
enough to see. (Formation, Classification, and Identification of
Igneous Rocks. (2000, September 29). In An Introduction to Igneous Rocks.
Retrieved June 16, 2013)
I took this picture while hiking at Fallen Leaf
Lake as well.

7. Crawdads (Crayfish)
This baby crawdad was
about 1.5 inches long and I
found him in the river above
Fallen Leaf Lake.
Crawdads evolved from a marine ancestor and I could not find a reliable
source for what the exact organism was that they evolved from.
"These crayfish were burrowing much like modern ones in the same area
today, showing that their behaviors haven't changed that much in more than
100 million years.“ (Ancient Crayfish Fossils Unravel Evolution Mystery. (2010, October 28). In National
Geographic. Retrieved June 16, 2013)

8. More fun facts about Crawdads!
Crawdads live in either slow moving water
or stagnant water usually around rocks. They
are not native to Lake Tahoe, but have been
here for many years.
The cannot survive in salt water even
though they evolved from a marine ancestor.
“In North America alone, two families, 12
genera, and at last count, over 390 species
can be found” (Fetzner, Jr., J. W. (1996). BIOCHEMICAL
SYSTEMATICS AND EVOLUTION OF THE CRAYFISH GENUS
ORCONECTES (DECAPODA: CAMBARIDAE) . In JOURNAL OF
CRUSTACEAN BIOLOGY, 16(1): 111-141, 1996. Retrieved June 16, 2013,

9. Duck Eggs in a Nest!
I found these Duck eggs in this nest at
Baldwin Beach! I saw the mother duck
fly away from the nest.
•These eggs belong to a Green-Winged Teal duck, scientifically known as
Anas crecca. (Roof, J. 1999. "Anas crecca" (On-line), Animal Diversity Web. Accessed June 24, 2013)
•After doing an extensive amount of research, it is unclear who the
ancestor is of the Green-Winged Teal ducks is.
•These ducks like in marsh land or wetlands, they eat seeds, and the
make their nests on the ground. (Davies, I. (n.d.). Green-winged Teal. In The Cornell Lab of
Ornithology. Retrieved June 16, 2013,)
This is a picture
of what the
mother looked
like.

10. Green-Winged Teals
These ducks are dabbler ducks ,and
they are the second most hunted
ducks in the United States next to
Mallards.
They lay an average of 10 creamy,
white eggs per season. Their
incubation period is about23 days.
In the wild, Green-winged teals live
an average of 243 months.
The female builds the nest while the
male watches, and once finish the
male abandons her. (Roof, J. 1999. "Anas
crecca" (On-line), Animal Diversity Web. Accessed
June 24, 2013)

11. Lily pads and Water Lilies
•“The leaf stem is hollow and
transports air from the surface to
the underwater rhizomes which
can grow to a massive size.” (Tan, R.
(2001). Water Lily (Nymphaea): info fact sheet,
photos. In Water Lily . Retrieved June 16, 2013,)
•Water lilies grow very well in
calm, fresh water. Like that of
marshes, ponds, and edges of
calm lakes.
• The scientific name for the water lily family is Nymphaeaceae. ((n.d.). In Wkipedia.
Retrieved June 15, 2013)
•“Modern genetic analyses by the Angiosperm Phylogeny Group researchers has
confirmed its basal position among flowering plants.” ((n.d.). In Wkipedia. Retrieved June 15,
2013)
•The genus of lily pads we have here in Lake Tahoe belongs to the Nymphaea,
which contains about 35 species and they are found in the Northern
Hemisphere.

12. References Formation, Classification, and Identification of Igneous Rocks. (2000, September 29).
In An Introduction to Igneous Rocks. Retrieved June 16, 2013, from
http://csmres.jmu.edu/geollab/fichter/IgnRx/Introigrx.html
 Facts About Lake Tahoe. (2012, December 13). In USGS. Retrieved June 15, 2013, from
http://tahoe.usgs.gov/facts.html
 Fetzner, Jr., J. W. (1996). BIOCHEMICAL SYSTEMATICS AND EVOLUTION OF THE
CRAYFISH GENUS ORCONECTES (DECAPODA: CAMBARIDAE) . In JOURNAL OF
CRUSTACEAN BIOLOGY, 16(1): 111-141, 1996. Retrieved June 16, 2013, from
http://iz.carnegiemnh.org/fetzner/pubs/Fetzner_1996_JCB16(1).pdf
 Ancient Crayfish Fossils Unravel Evolution Mystery. (2010, October 28). In National
Geographic. Retrieved June 16, 2013
 Roof, J. 1999. "Anas crecca" (On-line), Animal Diversity Web. Accessed June 24, 2013 at
http://animaldiversity.ummz.umich.edu/accounts/Anas_crecca/
 Davies, I. (n.d.). Green-winged Teal. In The Cornell Lab of Ornithology. Retrieved June 16,
2013, from http://www.allaboutbirds.org/guide/Green-winged_Teal/lifehistory
 Tan, R. (2001). Water Lily (Nymphaea): info fact sheet, photos. In Water Lily . Retrieved
June 16, 2013, from http://www.naturia.per.sg/buloh/plants/water_lily.htm
 Nymphaeaceae. (n.d.). In Wkipedia. Retrieved June 15, 2013, from
http://en.wikipedia.org/wiki/Nymphaeaceae
 Plant Guide. (2006, June 22). In USDA. Retrieved June 15, 2013, from
http://plants.usda.gov/plantguide/pdf/pg_pije.pdf