Download Standard 1a

Plate Tectonics
Standard 1a
1. The theory of Continental Drift
Continents were once together called Pangea. Then
drifted away from each other.
a. Four pieces of evidence were
i. Why the continents seem to fit together like
a jigsaw puzzle
ii. Why plant and animal fossils on S.
America were found across the ocean on
Africa.
iii. Also, similar type of rock and climatic
condition were found on S. America and
Africa.
iv. Similar Glacier patterns were also found
on these two continents.
b. Some scientists would not accept his theory
because:
c. Wegner could not come up with an explanation
as to what power could move continents.
d. He knew nothing of Plate Tectonics.
3. 2 reasons why the plates move
a. Sea floor spreading
i. New oceanic lithosphere is created as older
materials are pulled away.
ii. As the plates move away from each other,
the sea floor moves apart and magma rises
from the core, forming new crust.
iii. The oldest crust is found near the edges of
the continents.
iv. The newer crust is found near the center of
the oceans.
b. Convection
i. Warm water rising from the ocean floor, cooling
and then sinking. Warming up and rising again.
4. Plate Tectonics is the theory that:
i. The earth is made of plates
(lithosphere) that move on top of the
asthenosphere.
5. Plate Boundaries
b. Convergent
i. Two plates bumping into each other.
c. Divergent Boundaries
i. Plates moving away from each other
d. Transform Boundaries
i. Plates moving across from each other.
c. Movement of the plates cause:
a. Mountains, volcanoes
Tectonic Plate Movement
Standard 1c
1. The tectonic plates make the world look like a
jigsaw puzzle.
a. They fit together nicely.
b. Some plates contain both oceanic and
continental plates.
2. How fast do the plates move?
a. Usually so slow you can’t see or feel it
move.
i. They move centimeters per year.
ii. Very difficult to measure
1. GPS is used to measure
movement.
a. Global Positioning System
Results of Plate Motion
Standard 1e
1. Stress is the amount of force that is put on a given material.
a. The type of stress that occurs when an object is squeezed is
called Compression.
i. Rocky mountains
ii. Cascade range
b. Tension is stress that occurs when forces act to stretch an
object.
i. Occurs at divergent plate boundaries
ii. Causing rifts and faults
c. Folding
i. Bending of rock (p. 152)
2. Mountain Ranges
a. Most mountain ranges form at the edges of tectonic plates.
3. Earthquakes
a. Seismologist is a scientist that studies earthquakes.
i. Seismology is the study of earthquakes.
ii. A fault is a break in the earth’s crust due to sliding
1. Earthquakes are caused by this sliding
2. Faults
a. Can occur anywhere
i. Common near the edges of tectonic
plates
ii. This is why earthquakes are very
common near plate boundaries
4. Volcanoes
a. Formation of Volcanoes
a. Eruptions begin with magma forming in the upper regions of
the upper crust.
i. Pressure causes the magma to rise.
1. Not all magma reaches it to the surface.
2. Some solidifies under the crust.
b. Where do they form?
i. The Ring of Fire
1. These areas are also called Tectonic Plate
Boudaries. (p. 201)
2. The Ring of Fire contains 75% of the worlds
Volcanoes.
3. With plates constantly moving, it is easier for
Magma to reach the surface.
c. Divergent Boundaries
i. When plates separate
1. Magma rises to fill in the gap
a. Forming new crust.
d. Convergent Boundaries
i. Forces magma up through opening of volcano.
5. Tsunamis
a. Caused by:
i. Underwater earthquakes
ii. Volcanic eruptions
b. Occur mostly:
i. In the Pacific Ocean (Ring of Fire) p. 378
c. Deep in the ocean:
i. Can’t be see
1. Get much larger as they near the Continents
2. Some grow over 30m
Plate Tectonics
Layers of the Earth
Standard 1b
p. 136-39, 142, 160-1, 186-87, 200-03
1. Crust
a. Outer most layer of the earth
i. 5-100 km thick (1% of the earth)
ii. Thinnest layer of the earth
1. 2 types of crust
a. Oceanic
i. Thin
b. Continental
i. Thicker than Oceanic
2. Mantle
a. Between the crust and the core
i. 2,900 Km thick (67% of the earth)
ii. No human has ever seen the mantle
1. We know from what we see on the Earth’s
crust
2. Underwater Volcanoes
3. Core
a. Extends from the middle bottom of the mantle to the
center of the Earth
i. Diameter of 6,856 km thick (33% of the Earth)
ii. Larger than Mars.
4. Asthenosphere
a. Part of the Mantle
b. Lithosphere moves across it
c. Just below the Lithosphere
5. Lithosphere
a. Outermost layer of the Earth
b. Made of Tectonic Plates
Conduction and Convection
Standard 3c/4c
1. Conduction
a. Is the transfer of thermal energy (heat) from one
substance to another through direct contact.
i. Collisions transfer energy
1. Until both objects have the same amount of
energy (heat)
2. Convection
a. Is the transfer of thermal energy (heat) by the
movement of liquid or gas.