UMN ESCI 1101/1001 Final Exam
UPDATED QUESTIONS AND CORRECT
ANSWERS
Basaltic melt is produced by partial melting of
Basalt
Diorite
Peridotite - CORRECT ANSWER Peridotite
The fit of continents proposed by Alfred Wegener was based in part on matching coastlines between
continents.
True or False? - CORRECT ANSWER True
Marie Tharp played a key role in the discovery of mid-ocean ridges.
True or False? - CORRECT ANSWER True
The oceanic crust generates magnetic anomalies; these anomalies form stripes that are parallel to mid-
ocean ridges
True or False? - CORRECT ANSWER True
Magnetic anomalies exist because the Earth's magnetic field reverses frequently over geologic time.
True or False? - CORRECT ANSWER True
At mid-ocean ridges the oceanic crust is formed by decompression melting of upwelling mantle.
(True/False) - CORRECT ANSWER True
,Once formed, the oceanic lithosphere becomes thinner away from the mid-ocean ridge. - CORRECT
ANSWER False (the further ones continue to cool as new mantle progressively stacks)
Oceanic plates are recycled on the time scale of 20 million years - CORRECT ANSWER False
(200 millions years)
The San Andreas Fault in California is a transform fault. - CORRECT ANSWER True
At a subduction zone, the sediments between plates are squeezed and form an accretionary
prism/wedge. - CORRECT ANSWER True
As a function of distance away from a mid-ocean ridge, the age of the first sediments deposited on
oceanic crust decreases. - CORRECT ANSWER False (further from MOR=older)
The approximate temperature at the base of the lithosphere is (°C):
a. 130
b. 1300
c. 13000 - CORRECT ANSWER 1300°C
The thickness of continental crust under Minnesota is closest to (km):
a. 10
b. 40
c. 100
d. 400 - CORRECT ANSWER 40km
Subduction of oceanic plates occurs at plate boundaries where plates:
a. diverge
b. converge
, c. slide past each other - CORRECT ANSWER converge (diverge=split into 2, c is just no)
which is the correct set of arrows for motion on the transform fault?
a.
--------->
__________________________
<---------
or
b.
<---------
__________________________
---------> - CORRECT ANSWER b (see google)
Fracture zones in the oceanic crust accommodate dominantly:
a. horizontal motion
b. vertical motion - CORRECT ANSWER vertical motion
Hotspot - CORRECT ANSWER A weak spot in the middle of a tectonic plate where magma
surfaces; forms a volcano (ex: Hawaii & Yellowstone)
As a function of depth toward the center of Earth, temperature:
a. decreases
b. increases
c. remains constant - CORRECT ANSWER Increases
UPDATED QUESTIONS AND CORRECT
ANSWERS
Basaltic melt is produced by partial melting of
Basalt
Diorite
Peridotite - CORRECT ANSWER Peridotite
The fit of continents proposed by Alfred Wegener was based in part on matching coastlines between
continents.
True or False? - CORRECT ANSWER True
Marie Tharp played a key role in the discovery of mid-ocean ridges.
True or False? - CORRECT ANSWER True
The oceanic crust generates magnetic anomalies; these anomalies form stripes that are parallel to mid-
ocean ridges
True or False? - CORRECT ANSWER True
Magnetic anomalies exist because the Earth's magnetic field reverses frequently over geologic time.
True or False? - CORRECT ANSWER True
At mid-ocean ridges the oceanic crust is formed by decompression melting of upwelling mantle.
(True/False) - CORRECT ANSWER True
,Once formed, the oceanic lithosphere becomes thinner away from the mid-ocean ridge. - CORRECT
ANSWER False (the further ones continue to cool as new mantle progressively stacks)
Oceanic plates are recycled on the time scale of 20 million years - CORRECT ANSWER False
(200 millions years)
The San Andreas Fault in California is a transform fault. - CORRECT ANSWER True
At a subduction zone, the sediments between plates are squeezed and form an accretionary
prism/wedge. - CORRECT ANSWER True
As a function of distance away from a mid-ocean ridge, the age of the first sediments deposited on
oceanic crust decreases. - CORRECT ANSWER False (further from MOR=older)
The approximate temperature at the base of the lithosphere is (°C):
a. 130
b. 1300
c. 13000 - CORRECT ANSWER 1300°C
The thickness of continental crust under Minnesota is closest to (km):
a. 10
b. 40
c. 100
d. 400 - CORRECT ANSWER 40km
Subduction of oceanic plates occurs at plate boundaries where plates:
a. diverge
b. converge
, c. slide past each other - CORRECT ANSWER converge (diverge=split into 2, c is just no)
which is the correct set of arrows for motion on the transform fault?
a.
--------->
__________________________
<---------
or
b.
<---------
__________________________
---------> - CORRECT ANSWER b (see google)
Fracture zones in the oceanic crust accommodate dominantly:
a. horizontal motion
b. vertical motion - CORRECT ANSWER vertical motion
Hotspot - CORRECT ANSWER A weak spot in the middle of a tectonic plate where magma
surfaces; forms a volcano (ex: Hawaii & Yellowstone)
As a function of depth toward the center of Earth, temperature:
a. decreases
b. increases
c. remains constant - CORRECT ANSWER Increases
