Download Chapter 7 Study Guide TEST ON LESSON 1 Use your textbook

Chapter 7 Study Guide
TEST ON LESSON 1
Use your textbook, Dynamic Earth Web Quest, and notes from class to study the following
material for your test.
Lesson 1: Moving Plates
Vocabulary:
crust - Earth’s solid, rocky surface containing
the continents and the ocean floor.
magma - Hot, melted rock below the
Earth’s surface.
original horizontality - Rocks form in flat,
horizontal layers.
plate tectonics - The idea that Earth’s
surface is broken into plates (large pieces)
that slide slowly across the mantle.
continental drift – The idea that a
supercontinent split apart into pieces
-the continents, which drifted in time
to their present locations.
mantle – The hot, molten layer below
the Earth’s crust (the plates slide on the
mantle).
Pangaea
sea-floor spreading – the idea that new
crust is forming at ridges in the sea–floor
spreading apart the crust on either side
of the ridges.
subduction – the sliding of a denser ocean
plate under another plate when they
collide.
Know:
What was Wegener’s hypothesis? (Include 3 pieces of evidence for this hypothesis) D7
Wegener’s hypothesis stated that 200 million years ago, a supercontinent that he called
Pangaea, split apart into pieces that are now the continents. The continents drifted apart over
millions of years to where they are today. His hypothesis is known as continental drift.
Wegener noticed that: 1. The coastlines of Africa and South America looked like they might fit
together. 2. He discovered evidence that the same plant and animal fossils were found along
the coasts of these continents, although they were now separated by vast oceans. 3. He
noticed geological formations like mountain ranges, on the two continents also matched up.
What is the difference between continental drift and plate tectonics? D7,D11
Continental drift is the theory that the continents drifted apart over millions of years to their
present location.
Plate tectonics describes the Earth’s crust as broken into pieces (plates), and that each plate is
made of material from a layer below the crust called the mantle. The plates slide on the
mantle which explains the movement of the Earth’s crust.
Explain what happens during sea-floor spreading. D8-D9
The mid-ocean ridges are pushed up by hot rock material from deep beneath the crust. The
crust cracks where the sea-floor is spreading apart. Just below the ridges of the sea-floor,
there is hot, melted rock called magma. Magma flows up through the cracks, cools and
hardens into new solid rock along the ridges. The process keeps making new rock material
along the ridges and pushing older rock material farther away along the sea floor.
In what way is the convection current connected to the movement of the Earth’s plates?
D12-D14
Hot, molten rock called magma moves in the layers below the Earth’s plates. The movement
of the magma as it rises, cools, sinks and rises again is called the convection current. As the
magma rises and sinks it also moves the plates (pieces of the Earth’s crust).
What happens at divergent boundaries, convergent boundaries and transform boundaries?
D12-D13 and Dynamic Earth Web Quest
-At divergent plate boundaries the huge plates move apart. Sea-floor spreading takes place
here. As plates made of oceanic crust pull apart, a crack in the ocean floor appears. Magma
then oozes up from the mantle to fill in the space between the plates, forming a raised ridge
called a mid-ocean ridge. The magma also spreads outward, forming new ocean floor and
new oceanic crust.
-At convergent boundaries the huge plates move together, or collide.
When an ocean plate and a continental plate collide the denser ocean plate gets subducted,
or pulled underneath the continental plate. This forms what is called a subduction zone. As
the ocean crust sinks, a deep oceanic trench, or valley is formed at the edge of the continent.
The magma formed at the subduction zone rises up toward Earth’s surface and builds up in
magma chambers, where it feeds and creates volcanoes.
When two continental plates collide the rocks at the boundary crunch together and lift up
forming mountains
When two oceanic plates collide, a subducted zone is also generated. The older plate is forced
under the younger one, and it leads to the formation of chains of volcanic islands known as
island arcs.
-At transform boundaries the huge plates slide and grind past each other. Stress builds up at
the fault line and the stress is released in quick bursts when the plates suddenly slip into new
positions. The sudden movement is what we feel as the shaking and trembling of an
Earthquakes.
**Study the map of the plate boundaries on p. D11 and be able to locate the divergent,
convergent, and transform fault boundaries in between the plates.**