Chapter 13 plate tectonics

Chapter 13 plate tectonics
Name __Katerina Christopoulos
1. Tectonic plates are rigid pieces of the lithosphere. What is the lithosphere?
The lithosphere is the rigid outer part of the earth, consisting of the crust and
upper mantle.
2.Indicate whether the following are associated with the granitic or basaltic rock
_granitic_____________ continental crust
__basaltic rock____________ ocean crust (most of the lithosphere
___basaltic rock___________ high density plate material
___granitic___________ low density plate material
__granitic____________ thinnest plate
_basaltic rock_____________ thickest plate
3.The athenosphere:
a. Where is it?
It is primarily located in the upper layer of the earth’s mantle, and below the
lithosphere .
b. What important transfer of heat occurs here?
The convection cells. Driving force of plate tectonics.
c. Why is it important?
The upper part of the asthenosphere is the zone upon the rigid and
brittle lithospheric plates of the earth's crust movement.
4. The man who proposed the theory of drifting continents was
Alfred Wegner
Three evidences to support his theory:
Continental drift
1) Fossils
2) Climate Change
3) Rock Formation
4) Glacial deposit
5) Pangea (all contienents were one enjoined like a puzzle)
5.What two geologic events are common at plate boundaries?
Earthquakes and Volcanoes.
6. What strange occurrence has taken place with the Earth’s magnetic field in
past geologic history? 1) They are reversed. The magnetic poles have reversed.
7. The diagram below shows the magnetic orientation of igneous rock on the
seafloor on the east(right) side of a mid- ocean ridge. The pattern on the
west(left) side of the ridge has been omitted. The age of the igneous rock and its
distance from the ridge center are shown.
a. Which diagram below best represents the pattern of magnetic orientation in
the seafloor on the west(left) side of the ocean ridge? 2)
b. According to the diagram, what is the approximate rate of seafloor spreading?
(1)1km/million years
(3) 40km/million years
(2)2km/million years
(4) 50km/million years
c. Which inference can be best made from the diagram? 1)
1. The orientation of the Earth’s magnetic field has reversed with time
2. The size of the continents has changed with time.
3. The elevation of sea level has changed with time
4. The amount of fossil material preserved in the igneous rock has changed with
d. As distance from the center of the ridge increases, the age of the rocks
(1) decreases
(2) increases
(3) remains the same
8. Give 2 reasons heat flow provides evidence for rising convection currents at
spreading centers.
Magma pulls. Low density causes magma rocks to rise.
9. Match the following:
_a____ plates move apart
a. diverging boundary
__c___ plates move together
b. transform (sliding) boundary
___a__ new oceanic crust is formed
c. converging boundary
__b___ plates grind past each other
d. all of the above
__c___ oceanic crust is destroyed here
___d__ earthquakes occur here
___b__ oceanic crust is neither created or destroyed
10. F____ since ocean crust is continually being produced, the size of the earth
is increasing.
11. __F____ The oldest rocks in the ocean are near the mid-ocean ridges.
12.__F____ Measurements indicate that the west coast of Africa and the east
coast of South America are getting closer together.
13.___T___ Periodically, the Earth’s magnetic field reverses, that is the north
and south magnetic poles switch.
14.__T____ Rock possessing paleomagnetism indicate the direction of the
magnetic poles at the time the rocks crystallized.
15. Match the following:
__a___ Mid-Atlantic Ridge
__d___ San Andreas Fault
__b__ Himalaya Mountains
__b___ Andes Mountains
a. diverging plates
b. converging(continent-continent)
c. converging(ocean-continent)
d. transform(sliding) boundary
16. Explain or define:
a. SubductionThe sideways and downward movement of the edge of the plate of the earth’s
crust into the mantle beneath another plate
b. cratonA large, stable block of the earth’s crust forming the nucleus of a continent.
c. terraneA fault-bounded area or region with a distinctive stratigraphy, structure, and
geological history.