Field assignment

1. Geology Around The Tahoe
Basin
Gordon Gregory

2. Lake Tahoe
● Lake tahoe is one of the largest freshwater lakes in the world
● Lake tahoe is the tenth deepest lake in the world (“Interesting”)
● The lake is believed to be over 2 million years old (“interesting”)

3. Rock Bottom
You may notice that there is an
abundance of granite when looking
around tahoe. Being in the sierra
nevada mountains means that we
are on top of a batholith (“Sierra”). A
batholith is a massive formation of
cooled magma that is larger than 100
square kilometers (“Batholith”). The
sierra nevadas lie on top of a
batholith for hundreds of miles.

4. Sagebrush Lizard

5. The sagebrush lizard gets its name
from the fact that they tend to live in
the sagebrush bushes. These little
guys live in many of the
mountainous regions on the west
coast as well as in the deserts. They
like to hang out on rocks in the sun
since they are reptiles. They even
hibernate in the winter (“Western”).

6. Wyethia Mollis or Mule’s
Ear

7. Mule’s ear
● Native to the sierra nevadas and surrounding
areas
● The name comes from the small hairs that grow
off of the leafs of the plant
● Mule’s ear is actually a flower
● They grow in rocky soils and can grow in sand
(“Wyethia”).

8. Angora Ridge

9. In 2007 Angora ridge and the north
upper truckee area was hit by a large
wildfire that wiped out many of my
friends homes. The house I live in
now was burned down and rebuilt
after the fire. On one hand a lot of
families lost their homes but on the
other hand the area has some of the
nicest homes in town now. Fire
naturally occurs and allows regrowth.

10. Diorite

11. Diorite
● Here in the sierra nevadas we live on a batholith, which means there is an
abundance of igneous rocks. Igneous rocks form when molten rock hardens
(“What”).
● Diorite is easy fairly easy to spot with its light color and black dots.
● I believe this rock is diorite because I’ve seen it all my life and not know what
it was called but now that i have found a name to go with a picture it was
obvious to me.
● Diorite is used for many things from countertops to drainage (“Diorite”).

12. Andesite

13. Andesite
● Andesite is an extrusive igneous rock, meaning that the molten rock cooled
above the earth’s surface (“Andesite”).
● The rock I found was hard for me to identify but I believe it is andesite due to
the color and smaller grains that make it up.
● This particular example had many small marks that appeared to be from
erosion.

14. Gneiss

15. Gneiss
● What made me spot this rock was the bands across the upper side.
● Gneiss is a foliated metamorphic rock, which means that is has bands due to
heat and pressure (“Pictures of”).
● The bands are usually lighter than the rock’s color because the bands tend to
be made up of quartz and feldspar (“Pictures of”).

16. Angular unconformity

17. Angular Unconformity
● Angular unconformities indicate tectonic activity
(“Types”).
● This example is where I work at the base of twin peaks
and struck me as being the clearest example I’ve seen
around here without going on a hike. You can see that
the rock has been pushed or tilted upwards.
● I believe this example is has been eroded by snowmelt
running down the mountain for many years until it was
exposed

18. References
Batholith. (2019, June 06). Retrieved June 6, 2019, from https://en.wikipedia.org/wiki/Batholith
CaliforniaHerps.com, Reptiles and Amphibians of California. (n.d.). Retrieved June 5, 2019, from
http://www.californiaherps.com/lizards/pages/s.g.gracilis.html
Donaldson, C. (2015, June 03). Interesting Facts about Lake Tahoe. Retrieved June 6, 2019, from
http://www.thewilderling.com/2015/01/interesting-facts-lake-tahoe/
In, G. (1970, January 01). Types of Unconformities. Retrieved June 10, 2019, from http://www.geologyin.com/2015/10/types-of-
unconformities.html
King, H. (n.d.). Diorite. Retrieved June 8, 2019, from https://geology.com/rocks/diorite.shtml
King, H. (n.d.). Pictures of Igneous Rocks. Retrieved June 8, 2019, from https://geology.com/rocks/igneous-rocks.shtml
King, H. (n.d.). Andesite. Retrieved June 8, 2019, from https://geology.com/rocks/andesite.shtml
King, H. (n.d.). Gneiss. Retrieved June 9, 2019, from https://geology.com/rocks/gneiss.shtml
Sierra Nevada Batholith. (2019, January 02). Retrieved June 6, 2019, from https://en.wikipedia.org/wiki/Sierra_Nevada_Batholith
Wyethia mollis. (n.d.). Retrieved June 7, 2019, from https://www.laspilitas.com/nature-of-california/plants/3397--wyethia-mollis