Focus On Earth Science: California Grade 6

Chapter 4: Plate Tectonics

Standard Assessment

1.
Convection currents in Earth's mantle _______. 4.c
A)cause radioactive decay to occur in the mantle
B)transfer heat from Earth's surface to its interior
C)transfer heat from Earth's interior to its surface
D)are caused by plate movement
2.
As the temperature of a region of the mantle increases, it _______. 1.b
A)becomes more radioactive
B)becomes more dense
C)sinks
D)becomes less dense
3.
Wegener hypothesized that about 200 million years ago the supercontinent _______ began to break apart. 1.a
A)Pangea
B)Spitzbergen
C)Greenland
D)Cocos
4.
Why was Wegener's continental drift hypothesis rejected when he first proposed it? 1.a
A)No forces were known at that time that could cause continents to move.
B)His fossil evidence was incomplete.
C)Wegener's evidence was better explained by the seafloor spreading hypothesis.
D)He had made mistakes in dating his rocks and fossils.
5.
A lithospheric plate that sinks into the mantle must be _______. 1.c
A)heavier than the mantle
B)less dense than the mantle
C)thicker than the mantle
D)denser than the mantle
6.
Where does seafloor spreading occur? 1.c
A)at Spitzbergen
B)at ocean trenches
C)at mid-ocean ridges
D)in the middle of oceanic plates
7.
Oceanic plates are usually much _______ than continental plates. 1.b
A)heavier
B)thinner
C)thicker
D)lighter
8.
Which was not evidence presented by Alfred Wegener to support his hypothesis of continental drift? 1.a
A)the geographic fit of the continents
B)the distribution of certain fossils
C)reversals of Earth's magnetic polarity
D)locations of mountain ranges and rock types
9.
Measurements using the Global Positioning system and satellite laser ranging methods show that plates move at speeds of ______. 1.c
A)meters per day
B)meters per year
C)centimeters per day
D)centimeters per year
10.
Earth's outer layers are broken into pieces called _______. 1.c
A)lithospheric plates
B)plate tectonics
C)slabs
D)mid-ocean ridges
11.
The decay of radioactive elements in Earth's interior produces _______. 1.b
A)oceanic crust
B)magnetic reversals
C)continental crust
D)heat
12.
What type of rock is found in oceanic crust? 1.c
A)gneiss
B)granite
C)basalt
D)peridotite
13.
Which is caused by a dense plate sinking into the mantle? 1.c
A)convection
B)slab pull
C)seafloor spreading
D)ridge push
14.
Which mountain range in North America would have been connected to mountains now in Greenland, Great Britain, and Scandinavia? 1.a
A)Rocky
B)Cascade
C)Appalachian
D)Sierra - Nevada
15.
How does evidence of ancient glaciers in Africa, India, and Australia support Wegener's continental drift hypothesis? 1.a
A)The same mountain ranges must have exited on these continents for glaciers to form on all of them.
B)Glaciers could have formed only if these continents were part of the same supercontinent.
C)The formation of these glaciers was due to seafloor spreading.
D)These continents must have been in different locations were it was much colder.
Grade 6
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