Download Plate Tectonics Unit Test Study Guide

Plate Tectonics Unit Test Study Guide
I.
Different types of Volcanoes
1. Active – currently erupting or showing signs of erupting; has erupted in recorded history
2. Dormant – has not erupted in the last 10,000 years but could still erupt in the future
3. Extinct – not expected to ever erupt again
II.
Three Different Shapes of Volcanoes
1. Shield – large and broad, release fast moving, less gassy lava, tent to have less explosive
eruptions
2. Cinder Cone – smallest, most common, explosive eruptions, often on sides of larger volcanoes
3. Stratovolcano – Have explosive eruptions because of more gassy magma; formed by layers of
ash and lava
III.
Layers of the Earth
1. Crust – think outermost layer
2. Mantle – upper part is solid, lower is liquid
3. Outer Core – liquid iron
4. Inner core – solid iron, over 6000 degrees Celsius
5. Lithosphere – a Layer made up of the crust and top solid part of the mantle; makes up the
tectonic plates
IV.
Continental Drift
1. The idea that the continents were once a giant landmass, called Pangea, that broke into pieces
and slowly drifted away from each other.
2. Proposed by Alfred Wegener in 1915
3. Based on the following evidence”
i. Tropical plant fossils found in cold environments
ii. Marks left by glaciers in what are currently warm environments
iii. South America lines up well with the African coastline
iv. Rock layers match around the world in different locations
V.
Plate Tectonics
1. Says that large Sections of earth’s surface are made of lithospheric plates that move over the
mantle
2. Evidence includes:
i. Fossils of a lizard in both Brazil and South America
ii. Africa and south America fit together on a map
iii. Glacier marks in South Africa
iv. Coal on Arctic islands
v. Volcanoes on the ocean floor
3.
4.
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6.
vi. GPS data shows plates moving
Where lithospheric plates touch is called “plate boundaries”
Old crust is destroyed and new crust is formed at plate boundaries
The plates have moved and continue to move today
Helps to explain earthquakes, volcanoes and mountain formation
VI.
Earthquakes
1. Measured by a tool called a Seismograph that records the intensity of an earthquake
2. The Richter scale measures rock movement on a scale of 1-10
3. Mercalli Scale measures the damage done during an earthquake
4. Occur at convergent, divergent and transform boundaries
VII.
Plate Boundaries
1. Transform Plate Boundaries – plate slide past each other
i. Cause earthquakes and plate to move location
ii. Most commonly known is the plate in California between The north American plate and
the Pacific Plate
2. Divergent Boundary – plates move away from each other
i. Can cause earthquakes, volcanoes, and volcanic mountain formation
ii. New lithosphere often forms at this boundary
iii. Example: the boundary between the North American and Eurasian plate (that is
separating Iceland)
3. Convergent Boundary – plates are moving towards each other
i. Can cause earthquakes, volcanoes, and mountain formation
ii. At this boundary, crust is destroyed as it SUBDUCTS under one plate
iii. If both plates are continental crust, mountain ranges are formed.
1. Example: the Himalayan Mountains formed when India ran into the Eurasian
plate
iv. If one plate is oceanic and the other is continental, then the oceanic plate subducts
under the continental plate, eventually causing volcanoes and volcanic mountains to
form.
v. If both plates are oceanic plates, then mountain ranges are formed on the ocean floor.
VIII.
Convection
1. Convection Currents are the circulation of a fluid due to differences in temperature
2. When warm magma rises, cooler magma sinks creating convection currents in the mantle.
3. Convection currents in the mantle are what is moving the lithospheric plates.