Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Au 21: Introduction To Geology And So cietal Imp acts
Laboratory 2 : Plate Tectonics and the Rock Cycle
Due Oct 22 at 11:30pm Points 16 Questions 41
Available Oct 8 at 9am - Oct 22 at 11:30pm 15 days Time Limit None Allowed Attempts 2
Instructions
Use the quiz questions below to complete the answer sheet for the Laboratory 2 (Plate Tectonics and the Rock Cycle)
exercise. This lab is worth a total of 15 points.
The Prelab Video serves as an introduction to the topics covered in this lab. Find the Prelab Video here
(https://www.youtube.com/watch?v=b5P_OQ_5gyg&feature=youtu.be) .
NOTE ABOUT IMAGES : You can find all of the figures embedded in this quiz in Files --> Lab Instructions--> Lab 2: Plate Tectonics & the Rock
Cycle. Figures in the Questions are in that folder and are labeled with the relevant question number. Figures in the Introduction are within the folder
Figures in Introduction.
Lab 2 PDF file.
You have two attempts for this quiz.
Attempt History
Attempt Time Score
KEPT Attempt 2 6,330 minutes 14 out of 16 *
LATEST Attempt 2 6,330 minutes 14 out of 16 *
Attempt 1 142 minutes 12 out of 16 *
* Some questions not yet graded
Score f or this attempt: 14 out of 16 *
Submitted Oct 18 at 10:13pm
This attempt took 6,330 minutes.
Question 1 0..25 pts
Laboratory Honor Statement
Cheating or plagiarism of any kind will not be tolerated in ESS 101. This includes copying
answers f rom a f riend or classmate, copying answers verbatim f ound on the internet or
other literary sources, or copying any work that may answer the question being asked.
Make sure you always use your own words when answering the questions in the
homework and cite appropriate ref erences if you use them to help you answer the
question. Anyone caught violating the academic code of conduct
(https://www.washington.edu/cssc/for-students/academic-misconduct/) will receive a “0”
grade on the assignment, and if the conduct is deemed egregious, reported to the UW
Academic Misconduct representative.
I acknowledge that I have carefully read and understand the above statement regarding
the consequences of cheating and plagiarism, and promise to complete my work in this
1/31
, Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Au 21: Introduction To Geology And Societal Imp acts
class with honesty and integrity. Answer "True" below supporting your
acknowledgement.
Correct! True
False
Learning Goals:
By completing this lab, students will become more f amiliar with:
The three types of plate boundaries: convergent, divergent, and transf orm
The dif ferent types of magma associated with each type of plate boundary
The plate tectonic map of the Circum-Pacif ic Basin
The relationship between plate tectonics, volcanoes, and earthquakes
The Hawaii-Emperor Seamount chain and using distance-time relationships of the
volcanic islands to describe historical tectonic movement
Plate Tectonics
Overview
Plate tectonics links together many aspects of geology. Plate tectonics describes how the
earth’s thin, outer lithosphere is broken into plates that slowly move over the asthenosphere
(Figure 2-1). These brittle rock plates have thicknesses of 10 to 100 km and move over the
ductile rock of the asthenosphere at rates of 1 to 10 cm/year. This is about the same rate at
which your f ingernails grow! The f orces that drive plate motion are primarily ridge-push and
slab-pull gravity f orces. See Incorporated Research Institutions for
Seismology video on the forces that drive plate tectonics (select animation tab).
(https://www.iris.edu/hq/inclass/animation/what_are_the_forces_that_d rive_plate_tectonics)
2/31
, Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Au 21: Introduction To Geology And Societal Impacts
Figure 2-1: Earth’s tectonic plates. The black lines indicate the boundaries between plates, and the
red arrows indicate the relative motions at plate boundaries .
1
Chemical and physical layers of the earth
Earth’s structure can be classified by chemical composition or by physical properties. The
chemical layers of the Earth are the crust, mantle, and core. The crust is mainly composed
of igneous rocks (that is, rocks that f ormed when hot magma cooled at earth’s surf ace).
Continental crust is made of felsic (silica-rich) rocks like granite, and oceanic crust is
made of mafic (silica-poor) rocks such as basalt. Below the crust is the mantle, which is
made of silicate minerals that are rich in iron and magnesium. Generally, rocks that are
silica-rich tend to have relatively lower iron-magnesium (Fe-Mg) content.
The physical layers of the outer earth are the lithosphere and the asthenosphere (Figure 2-
2). Tectonic plates are pieces of the lithosphere, a layer of brittle rock. The plates slide over
the asthenosphere, a layer of ductile, mantle rock.
2
Figure 2-2: Cross-section of the outer solid Earth . The lithospheric plates slide over the
asthenosphere. Oceanic lithosphere forms at mid -ocean ridges (divergent margins) and descends
back into the asthenosphere in subduction zones (convergent margins).
Plate Boundaries
Volcanoes and mountains form at plate boundaries, and plate boundaries produce strong
earthquakes. There are three types of plate boundary:
1. Divergent, where two plates are moving apart.
2. Convergent, where two plates are moving together. There are three dif ferent types of
convergent margins:
Ocean-ocean, where oceanic crust converges with oceanic crust. At this type of
margin, the denser of the two plates will dive beneath the other, and create a
subduction zone (e.g. the Marianas Trench).
Ocean-continent, where oceanic crust converges with continental crust. At this
type of margin, the denser oceanic crust will dive beneath the less dense
continental crust and create a subduction zone (e.g. the Cascadia subduction
zone).
Continent-continent, where continental crust converges with continental crust. At
this type of margin, both plates are relatively buoyant and do not want to sink down.
Theref ore, subduction does not occur and the two plates collide together to f orm
3/31
, Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Au 21: Introduction To Geology And Societal Impacts
mountain ranges such as the Himalaya Mountains (formed by the collision of the
Indian and Eurasian plates).
3. Transform, where two plates with ocean and/or continental crust are sliding past each
other.
Volcanoes
Volcanoes are places where liquid rock erupts onto the surf ace of the earth. Volcanoes
of ten form at divergent and convergent boundaries, but they can also form in the middle of
plates due to mantle hot spots or rif ting. Some important concepts and distinctions f or
volcanic systems include:
Magma is liquid rock f ound beneath the surf ace of the Earth.
Lava is liquid rock f ound on the surf ace of the Earth.
Igneous rocks f orm when magma or lava cools into a solid.
Volcanic rocks are igneous rocks that f orm on the surf ace (where cooling of lava is
rapid), and plutonic rocks are igneous rocks that form underground (where cooling of
magma is slow).
Plate Boundary Volcanoes:
(1) Divergent Margins
As two plates move apart, the space that was once occupied by the plates is replaced by
upwelling mantle asthenosphere. As this mantle material ascends, it experiences
decreasing pressures, which causes it to melt. This process is known as decompression
melting. Eventually, this melt either reaches the surf ace as basaltic lava and cools to
create a new crust, or it cools as basaltic magma beneath the surf ace to create new
mantle lithosphere. All oceanic lithosphere is created in this way at mid -ocean ridges
(Figure 2-3).
Figure 2-3: Divergent plate margin and zone of upwelling of magma. Oceanic lithosphere is generated
at the ridge axis, cooling and increasing in thickness as it moves away from the plate margin. [From
Igneous Petrogenesis by M. Wilson.]
(2) Convergent Margins
At convergent margins, if one plate is denser than the other it will subduct beneath the less
dense plate, f orming a subduction zone. Subduction zone magmas f orm when the
downgoing plate is heated and thus dehydrated. The water squeezed out of the subducting
plate lowers the melting point of the rocks in the overlying mantle and initiates melting. This
is like how adding salt to ice lowers the melting point of the ice, allowing the ice to melt at a
4/31
Laboratory 2 : Plate Tectonics and the Rock Cycle
Due Oct 22 at 11:30pm Points 16 Questions 41
Available Oct 8 at 9am - Oct 22 at 11:30pm 15 days Time Limit None Allowed Attempts 2
Instructions
Use the quiz questions below to complete the answer sheet for the Laboratory 2 (Plate Tectonics and the Rock Cycle)
exercise. This lab is worth a total of 15 points.
The Prelab Video serves as an introduction to the topics covered in this lab. Find the Prelab Video here
(https://www.youtube.com/watch?v=b5P_OQ_5gyg&feature=youtu.be) .
NOTE ABOUT IMAGES : You can find all of the figures embedded in this quiz in Files --> Lab Instructions--> Lab 2: Plate Tectonics & the Rock
Cycle. Figures in the Questions are in that folder and are labeled with the relevant question number. Figures in the Introduction are within the folder
Figures in Introduction.
Lab 2 PDF file.
You have two attempts for this quiz.
Attempt History
Attempt Time Score
KEPT Attempt 2 6,330 minutes 14 out of 16 *
LATEST Attempt 2 6,330 minutes 14 out of 16 *
Attempt 1 142 minutes 12 out of 16 *
* Some questions not yet graded
Score f or this attempt: 14 out of 16 *
Submitted Oct 18 at 10:13pm
This attempt took 6,330 minutes.
Question 1 0..25 pts
Laboratory Honor Statement
Cheating or plagiarism of any kind will not be tolerated in ESS 101. This includes copying
answers f rom a f riend or classmate, copying answers verbatim f ound on the internet or
other literary sources, or copying any work that may answer the question being asked.
Make sure you always use your own words when answering the questions in the
homework and cite appropriate ref erences if you use them to help you answer the
question. Anyone caught violating the academic code of conduct
(https://www.washington.edu/cssc/for-students/academic-misconduct/) will receive a “0”
grade on the assignment, and if the conduct is deemed egregious, reported to the UW
Academic Misconduct representative.
I acknowledge that I have carefully read and understand the above statement regarding
the consequences of cheating and plagiarism, and promise to complete my work in this
1/31
, Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Au 21: Introduction To Geology And Societal Imp acts
class with honesty and integrity. Answer "True" below supporting your
acknowledgement.
Correct! True
False
Learning Goals:
By completing this lab, students will become more f amiliar with:
The three types of plate boundaries: convergent, divergent, and transf orm
The dif ferent types of magma associated with each type of plate boundary
The plate tectonic map of the Circum-Pacif ic Basin
The relationship between plate tectonics, volcanoes, and earthquakes
The Hawaii-Emperor Seamount chain and using distance-time relationships of the
volcanic islands to describe historical tectonic movement
Plate Tectonics
Overview
Plate tectonics links together many aspects of geology. Plate tectonics describes how the
earth’s thin, outer lithosphere is broken into plates that slowly move over the asthenosphere
(Figure 2-1). These brittle rock plates have thicknesses of 10 to 100 km and move over the
ductile rock of the asthenosphere at rates of 1 to 10 cm/year. This is about the same rate at
which your f ingernails grow! The f orces that drive plate motion are primarily ridge-push and
slab-pull gravity f orces. See Incorporated Research Institutions for
Seismology video on the forces that drive plate tectonics (select animation tab).
(https://www.iris.edu/hq/inclass/animation/what_are_the_forces_that_d rive_plate_tectonics)
2/31
, Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Au 21: Introduction To Geology And Societal Impacts
Figure 2-1: Earth’s tectonic plates. The black lines indicate the boundaries between plates, and the
red arrows indicate the relative motions at plate boundaries .
1
Chemical and physical layers of the earth
Earth’s structure can be classified by chemical composition or by physical properties. The
chemical layers of the Earth are the crust, mantle, and core. The crust is mainly composed
of igneous rocks (that is, rocks that f ormed when hot magma cooled at earth’s surf ace).
Continental crust is made of felsic (silica-rich) rocks like granite, and oceanic crust is
made of mafic (silica-poor) rocks such as basalt. Below the crust is the mantle, which is
made of silicate minerals that are rich in iron and magnesium. Generally, rocks that are
silica-rich tend to have relatively lower iron-magnesium (Fe-Mg) content.
The physical layers of the outer earth are the lithosphere and the asthenosphere (Figure 2-
2). Tectonic plates are pieces of the lithosphere, a layer of brittle rock. The plates slide over
the asthenosphere, a layer of ductile, mantle rock.
2
Figure 2-2: Cross-section of the outer solid Earth . The lithospheric plates slide over the
asthenosphere. Oceanic lithosphere forms at mid -ocean ridges (divergent margins) and descends
back into the asthenosphere in subduction zones (convergent margins).
Plate Boundaries
Volcanoes and mountains form at plate boundaries, and plate boundaries produce strong
earthquakes. There are three types of plate boundary:
1. Divergent, where two plates are moving apart.
2. Convergent, where two plates are moving together. There are three dif ferent types of
convergent margins:
Ocean-ocean, where oceanic crust converges with oceanic crust. At this type of
margin, the denser of the two plates will dive beneath the other, and create a
subduction zone (e.g. the Marianas Trench).
Ocean-continent, where oceanic crust converges with continental crust. At this
type of margin, the denser oceanic crust will dive beneath the less dense
continental crust and create a subduction zone (e.g. the Cascadia subduction
zone).
Continent-continent, where continental crust converges with continental crust. At
this type of margin, both plates are relatively buoyant and do not want to sink down.
Theref ore, subduction does not occur and the two plates collide together to f orm
3/31
, Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Au 21: Introduction To Geology And Societal Impacts
mountain ranges such as the Himalaya Mountains (formed by the collision of the
Indian and Eurasian plates).
3. Transform, where two plates with ocean and/or continental crust are sliding past each
other.
Volcanoes
Volcanoes are places where liquid rock erupts onto the surf ace of the earth. Volcanoes
of ten form at divergent and convergent boundaries, but they can also form in the middle of
plates due to mantle hot spots or rif ting. Some important concepts and distinctions f or
volcanic systems include:
Magma is liquid rock f ound beneath the surf ace of the Earth.
Lava is liquid rock f ound on the surf ace of the Earth.
Igneous rocks f orm when magma or lava cools into a solid.
Volcanic rocks are igneous rocks that f orm on the surf ace (where cooling of lava is
rapid), and plutonic rocks are igneous rocks that form underground (where cooling of
magma is slow).
Plate Boundary Volcanoes:
(1) Divergent Margins
As two plates move apart, the space that was once occupied by the plates is replaced by
upwelling mantle asthenosphere. As this mantle material ascends, it experiences
decreasing pressures, which causes it to melt. This process is known as decompression
melting. Eventually, this melt either reaches the surf ace as basaltic lava and cools to
create a new crust, or it cools as basaltic magma beneath the surf ace to create new
mantle lithosphere. All oceanic lithosphere is created in this way at mid -ocean ridges
(Figure 2-3).
Figure 2-3: Divergent plate margin and zone of upwelling of magma. Oceanic lithosphere is generated
at the ridge axis, cooling and increasing in thickness as it moves away from the plate margin. [From
Igneous Petrogenesis by M. Wilson.]
(2) Convergent Margins
At convergent margins, if one plate is denser than the other it will subduct beneath the less
dense plate, f orming a subduction zone. Subduction zone magmas f orm when the
downgoing plate is heated and thus dehydrated. The water squeezed out of the subducting
plate lowers the melting point of the rocks in the overlying mantle and initiates melting. This
is like how adding salt to ice lowers the melting point of the ice, allowing the ice to melt at a
4/31
