Download Building California by Plate Tectonics

Chapter 6, Section 4: California Geology
1. bathalith: a large mass of igneous rock in Earth’s crust
2. Accreted terrane: a piece of lithosphere that becomes part of a larger landmass
when tectonic plates collide at a convergent boundary.
Building California by Plate Tectonics:
Main Idea:
Notes:
-How has Plate Tectonics
affected California?
*Compression along the plate boundaries has
produced many of the rugged mountains along
with steep, rocky coastlines and basins that lie in
between these mountain ranges.
-How did California come about
*The area that we know as California has been an
it’s geologic history?
active plate boundary for more than 225 million
years.
* due to the existence of 3 plates: North American
Plate, Farallon Plate, and the Pacific Plate.
*A convergent boundary existed between the North
American Plate and the Farallon Plate. The Farallon
Plate subducted beneath the North American Plate.
As the Farallon Plate subducted the Pacific Plate
moved closer to the North American Plate. Once the
Pacific and North American Plates touched, a
Transform Boundary was born.
How were the Cascade
The Juan de Fuca Plate has subducted under the
Mountains formed?
North American Plate creating a convergent boundary
in Northern California, Oregon, and Washington. This
boundary created the Cascade Mountains.
Accreted Terrane:
The chunks of lithosphere that are scraped off of
subducting plates and are added to the edge of a
continent. The rocks west of the Sierra Nevada are
thought to be pieces of accreted terrane which carry
most of California’s gold.
The San Andreas Fault System:
-The largest and most famous transform plate
boundary in the world.
-Most of California is on the North American Plate.
A small section, west of the San Andreas Fault is on
the Pacific Plate.
-Along the San Andreas Fault, the Pacific Plate is
moving northwest while the North American Plate is
moving southeast.
-Compression in Southern California. The fault has a
huge bend as it passes east of the city of Los Angeles.
The bend causes the boundaries to collide and form
mountains and valleys. This is how the Los Angeles
Basin was formed.