2. Content
Fallen Leaf Geological Background
Geological Features
Snow Plant History
Mallard (Anas Platyrhincos) History
Metamorphic Rock
Igneous Rock
3. Fallen Leaf Geological
Background
• Similar ecosystem to the
rest of the basin
• Formed during the
Pleistocene glaciation
• Glaciers left behind
polished granite rocks
• The Fallen Leaf moraines
were formed by the large
Tahoe glacial episode,
70,000 to 150,000 years
ago
•Watersheld covers an area of about
42 square km
• Trees consist of common Jeffrey,
Ponderosa and Lodgepole pines, also
some non native quaking aspens in
the area
4. Geological Features
Terminal Moraine-
accumulation of ridge-
like rock debris, pushed
forward by glacial activity
Lateral Moraine- debris
derived by erosion and
avalanche from the
valley wall onto the edge
of a glacier and
depositing as an
elongated ridge
Medial Moraine- formed by
two glaciers from the east
and west
5. Geological Features
• Fallen leaf Moraines
– Angora and Cathedral ridge
• Medial moraines
– Strip of land between Lake
Tahoe and Fallen Leaf
• Two terminal moraines
– North end of lake is shallow and
south end marks the terminal
moraines with a sharp drop off
– Two moraines suggests the glacier
retreated more than once
6. Snow Plant History
Sarcodes sanguinea
• Occurs through out Sierra
Nevadas, Southern Oregon,
Western Nevada and
Northern Mexico
• Non-photosynthetic and
receives all nutrients from
fungal root symbionts
• Receives all carbon from fir
host tree through mycorrhizal
• Suggests algal ancestor
with similar symbiotic,
mineral absorbing fungus
7. Mallard History
Anas playtrhincos
• Ancestors to wild
ducks thought to
have appeared
during the time of the
dinosaurs
– Pliocene or early
Pleistocene epoch
– About 2 mya, in
present day Siberia
8. Mallard History
Anas playtrhincos
• Ancestors to all
domesticated
ducks
– Hybridize with about
45 other species of
ducks and are
thought to destroy the
mallard species
completely if
continued
9. Metamorphic Rock
• Marposa Slate
– Fine grained, foliated metamorphic rock
– Formed when pre-existing rocks are
subject to extreme heat and/or pressure
– Composed of clay minerals or micas
10. Metamorphic Rock
• Formation of Slate
– Created in formally sedimentary basin that
becomes involved in a convergent
boundary
– Forces and heat modify clay minerals
– Foliation develops at right angles to the
compressive forces to yield vertical
foliation
11. Igneous Rock
• Quartz Monzonite Granite
– Dominant igneous rock
found in the basin
– Light colored, granular and
course-grained
• Made up of quartz,
plagioclase feldspar,
potassium feldspar
– Lesser amounts of biotite,
hornblend and other
minerals
Granite formations
nearby at Angora
Lake
12. Igneous Rock
• Formation of
granite
– Minerals
crystallized from
magma, cooled
deep below earths
crust
• Three-six miles
deep
– Magma cooled
slowly, allowing
large crystals to
form
13. 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 June
2013. <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>
