Unit title: Plate Tectonics.

Learning Area: Science – earth sciences.

Content Descriptor: The theory of plate

tectonics explains global patterns of

geological activity and continental

movement. (ACSSU180)

Year: 9

Date: 24.05.2015

Outcomes:

Identify the major plates of the earth and develop an understanding of plate tectonics; the

influence plate movement has on the surface of the earth (i.e. earthquakes, tsunamis, and

volcanoes).

Comprehend the role heat has on the movement of the earth’s tectonic plates.

Introduction:

Science is a vital aspect of a student’s education experience, covering a wide range of

concepts and topics. The implementation of curriculum differentiation is of significance

when considering the diverse learning needs in the classroom, where reasonable adjustments

and adaptations are required for student participation. The inclusion of scaffolding into a

lesson is essential to ensure all the students learning needs are met. As a teacher it is

important to challenge and develop the knowledge and understanding of the students, and

maintain high learning expectations (Ministerial Council on Education, Employment,

Training, and Youth Affairs [MCEETYA], 2008).

Rationale.

The development of inquiry skills; investigative, analytical, and communication are

important components derived primarily from the science area of education (Tasmanian

Qualification Authority [TQA], 2013). Earth science requires student to develop and

demonstrate an understanding of geological processes, with links made the real scenarios.

Student will develop the ability to comprehend and respond to questions, while making

connections between underlying processes and sub sequential events.

This unit plan incorporates a variety of activities at different levels of achievement standards.

However this lesson sequence integrates the Visual, Auditory, and Kinesthetic (VAK)

learning styles model (Kodesia, 2014), it potential benefit from additional visual components

such as video clips and time lapse animations. The majority of activities throughout the

lesson sequence are aimed at a sound standard, requiring the students to demonstrate basic to

advanced understanding of the concept and plate movements. The integration of reading

activities is utilised to reinforce the underlying processes and demonstrate and improve the

students reading comprehension and interpretation capabilities. Inquiry one is a hands-on

activity designed and incorporated for the kinesthetic learners in the class, to allow them to

express their understanding of the concept. Whereas, inquiry two, is a research based

investigation which may present beneficial for those of visual and auditory learning styles.

Assessment Tasks/Evaluation.

The assessment tasks designed for this lesson sequence provide three opportunities for the

students to demonstrate their knowledge and understanding of the topic, plate tectonics. The

formative and summative assessment strategies are both integrated into this lesson sequence,

with both inquiry activities being conducted in a formative structure, while and end of unit

test is delivered in a summative manner. The incorporation of both strategies allows for the

different learning styles adopted by the students. As for the evaluation of the assessment

tasks students will be marked on a scale of: below standard, at standard and above standard.

Below standard, the student is unable to demonstrate a sound understanding, and has

achieved a basic level of competence of the topic. No descriptive explanations provided, and

minimal connections made between the movement of tectonic plates and the consequential

events generated.

At standard, the student demonstrates a sound understanding of the main content areas of

the topic and has achieved an adequate competence level, providing descriptive explanations

and illustrations relative to the theory of plate tectonics. Connections and links have been

identified between the movement of tectonic plates, associated plate boundaries and the

potential effects generated. The utilisation of new terminology not always correctly applied

to scenario.

Above standard, the student demonstrates a thorough understanding of the content,

achieving a high competence level of the topic. Explanations are descriptive, with illustration

support. Strong connections between tectonic plate movements/plate boundaries and

subsequent events are identified with supported reasoning. Terminology is generally utilised

in correct application.

Literacy and Numeracy in the Lesson sequence.

This lesson sequence is embedded with a variety of literacy and numeracy elements, to

enhance and develop the students understanding. Literacy element: language and vocabulary,

and reading comprehension. The terminology and language utilised within the lesson

sequence, broaden and extend the students vocabulary. Reading activities were designed to

reinforce underlying processes of plate tectonics, meanwhile developing the level of reading

comprehension and interpretation of texts.

Numeracy elements such as: Recognising and using patterns and relationships, and

Spatial reasoning are integrated into this lesson sequence, where students are required to

identify and describe trends and patterns observed and make connections between theory and

real world scenarios. The incorporation of spatial reasoning in this lesson sequence enhances

the students’ ability to interpret maps and diagrams, while visualising 2D and 3D objects,

describing key environmental features.

Unit Content:

What minerals and elements make-up the earth? Major elements are: Iron (Fe), Magnesium

(Mg), Silicon (Si), and Oxygen (O₂).

The earth is made up of 3 concentric layers:

Core: 2 parts make the core: outer and inner.

What are the characteristics of the core?

Mantle :2 sub-layers of the mantle: brittle and soft

What are the characteristics of the mantle?

Crust: 2 types of crust: oceanic and continental

What are the characteristics of the crust?

What are the key differences between oceanic crust and continental crust? Oceanic is

comprised of basalt, whereas continental is granite.

Why is the crust of the earth of importance? The earth’s crust is divided up into a number of

discrete pieces known as plates.

ACTIVITY: World map – colour each of the 15 Tectonic Plates in a different colour.

Figure 1. Basic Internal Structure of earth. Modified

and retrieved from: http://geology.com/nsta/earth-

internal-structure.shtml

Figure 2. Map of the Tectonic Plates. Retrieved from

http://en.wikibooks.org/wiki/High_School_Earth_Science/Volcanic_Activity

The earth can also be divided up into 5 different mechanical components: (surface to centre)

Lithosphere, Asthenosphere, Mesosphere Outer Core & inner Core.

Lithosphere: Crust & Upper Mantle, rigid, bends, flexes, &/or breaks when acted on

by force.

Asthenosphere: Mid Mantle, soft/plasticity layer, flows when acted on by force.

Mesosphere: Lower Mantle, rigid.

Outer Core: liquid/magma

Inner Core: Solid

Figure 3. Internal structure of Earth: Compositional and Mechanical. Modified and retrieved

from: http://www.visionlearning.com/en/library/Earth-Science/6/Earth-Structure/69

Reading Activity (See Appendix 1.1 for reading)

- Reading one is based on the internal structure of the earth.

Question: What is the role of heat in the movement of tectonic plates?

Lesson Three – Theory of Plate Tectonics, Historical perspective.

What is Plate Tectonics? Plate tectonics refers to the movement of the lithosphere plates;

plates move relatively slowly approximately 10cm per year (Marshak, 2008).

Why are the movements of tectonic plates of significance? Tectonic plate movement has the

ability to generate earthquakes, volcanoes, tsunamis, mountain ranges and cause the

distribution of continents to change over time (Marshak, 2008).

Wegener’s Theory.

Wegener’s theory of Continental Drift suggest that all continents where once joined forming

a supercontinent known as Pangaea, and slowly over time breaking off and moving away

from one another.

Figure 4. Continental drift; the break-up of Pangaea to present day. Retrieved from:

http://www.mun.ca/biology/scarr/Pangaea.html

The idea that the continents fit together by matching coastlines and the locations of past

Glaciers, and the distribution of fossils; Mesosaurus, Cynognathus, Lystrosaurus, and

Glossopteris, gave Wegener enough evidence to suggest continents were once joined, to

allow for a wide distribution of fossils, and glaciers (Marshak, 2008).

Wegener’s evidence supporting his hypothesis of continental drift, were not primary

evidence and were subject to scrutiny, as Wegener had no explanation as to how the

continentals were able to drift apart, as continent were viewed as immobile and fixed into

position (Marshak, 2008).

“What force could possibly be great enough to move the immense mass of a continent?” was

the question asked at the 1926 Geology conference held in New York (Marshak, 2008).

Today Geologists accept Wegener’s theory of Continental Drift. In the 1960’s the process of

seafloor spreading was introduced, suggesting that the continents drift apart due to new

ocean floors being formed, however if the seafloor is spreading then there must be regions

where the seafloor must sink back into the earth, these regions are known as subduction

zones (Marshak, 2008).

Reading Activity (See Appendix 1.2, 1.3, 1.4 for readings)

- Reading two highlights Wegener’s theory of continental drift.

Question: What evidence did Wegener have to support his hypothesis?

- Reading three explore the evidence Wegener needed to support the hypothesis of

continental drift.

Question: What was located in the Atlantic Ocean that provided evidence to support

Wegener’s theory of continental drift?

- Reading four outlines the formation and break up of Pangaea to present day.

Question: Outline the break up process of Pangaea?

Lesson Four & Five – Plate Boundaries.

What is a plate boundary? Plate boundaries are regions where one plate connects with

another.

3 Plate Boundaries: Divergent, Convergent, and Transform.

Divergent (Separate): Two plates moving away from one another; resulting in Mid-

Ocean Ridges, and seafloor spreading.

Convergent (Collide): Two plates moving towards each other collide, one plate sinks,

or subducts beneath the other. Results in trenches, mountain ranges, and subduction

zones.

- Continental & Continental: plates collide and thrust upwards, resulting in mountain ranges.

- Continental & Oceanic: Oceanic Lithosphere subducts beneath the Continental

Lithosphere

- Oceanic & Oceanic: subduction; one lithosphere plate with slip underneath the other.

ONLY OCEANIC LITHOSPHERE CAN UNDERGO SUBDUCTION.

Transform (Slide): one plate slips past another plate, Resulting in a Fault

Fault: A Fracture on which one body of rock slides past another.

Triple Junction: A point where 3 plate boundaries intersect.

ACTIVITY - World Map with Plate boundaries marked, colour all plate boundaries you can

identify.

Divergent Boundary = Yellow Transform Boundary = Blue

Convergent Boundary = Red Triple Junction = Green

Figure 5. Map of tectonic plates and plate boundaries. Retrieved from:

http://en.wikibooks.org/wiki/High_School_Earth_Science/Volcanic_Activity

INQUIRY ONE – Hands-on inquiry: Model plate movement.

Model the underlying process/plate movement happening at the plate boundary, to illustrate

how plates interact at the plate boundaries. (See Appendix 2. for activity materials and

directions).

In groups of 3-4 students, groups are assigned a type of plate boundary: divergent, transform,

convergent – continental/continental, and convergent – continental/oceanic.

Activity “Snack tectonics” retrieved from:

http://www.windows2universe.org/teacher_resources/teach_snacktectonics.html

Individually draw and illustrate plate movement occurring at the plate boundary?

What are the key characteristics of this plate boundary?

What could this plate movement potentially generate?

Reading Activity (See Appendix 1.5 for reading)

- Reading five describes the processes occurring at convergent and transform plate

boundaries.

Question: What famous mountain range was created from a convergent plate boundary,

consisting of only continental crust?

Lesson Six – Plate Tectonic Events.

Plate movements have resulted in a number of natural events, NOT ALL ARE DISASTERS.

Earthquakes: caused by a sudden breaking or frictional sliding of rock in earth,

potential to trigger tsunami.

Volcanoes: A vent from which melt/magma from inside the earth overflows onto the

earth’s surface.

: A mountain formed by the accumulation of extrusive volcanic rock.

Mountain ranges: Rise due to plate movement; Convergent Boundary of Continental

& Continental Lithosphere colliding and thrusting upwards forming mountain ranges

such as the Himalayas.

Seafloor spreading: Gradual widening of an ocean basin as a new oceanic crust is

formed at a mid-ocean ridge axis and then moves away from the axis.

INQUIRY TWO – Investigation of a tectonic event.

Focus Question: How are the movements of tectonic plates the related to earthquakes,

tsunamis, and volcanoes?

Pick one of the recent events listed below to research; identify the causation of this effect.

Investigation Questions.

What tectonic plates are involved?

What type of plate boundary is present?

What effect would you predict to occur, based on the tectonic plates and boundaries present

in this region? Why?

Would you consider the area of impact a hot spot for potential tectonic linked events in the

future? Why?

Tell the story of what has occurred for this tectonic event to take place?

Tectonic linked events:

Nepal earthquake (2015)

Christchurch (New Zealand) earthquake (2011)

Iceland (Grímsvötn) Volcano, last eruption (2011)

Chilean (Puyehue-Cordon Caulle) Volcano, last eruption (2011)

Indonesian Tsunami (2004)

Japan Tsunami (2011)

Lesson Seven & Eight – Activity of real scenarios and Summary.

ACTIVITY

Looking back in time at the top 10 earthquakes, tsunamis, and volcanoes (See Appendix 3.

for list of events).

Investigation questions.

Are these regions in high tectonic impact areas?

What plates were involved?

What plate boundary generated this event?

Would you consider the region of high significance for future events?

This activity is designed to highlight the strong correlation between plate boundaries and the

locations of earthquakes and volcanoes.

Multimedia Resource: Tectonic Plates, Earthquakes, and Volcanoes.

http://www.pbslearningmedia.org/resource/ess05.sci.ess.earthsys.tectonic/tectonic-

plates-earthquakes-and-volcanoes/

End Of Unit Test (See Appendix 4.)

Multiple choice and short answer test.

Identifying the strengths/weaknesses, and gaps in the knowledge and understanding

of the topic of plate tectonics.

Learner assessment:

Formative:

Inquiry one – demonstrating a basic knowledge of the topic

Inquiry/Investigation – illustrating an understanding of plate tectonics and how plate

movement can influence the surface of the earth.

Summative:

End of unit test – highlights the understanding generated from the unit

Unit evaluation:

How did the class react to the topic? What was successful in the Unit? What sections need

improvement? Did the activities and inquiries demonstrate a good understand of the topic

plate tectonics? What was the overall outcome of the unit (successful or unsuccessful)?

Adapted and modified from Killen, R. (2010) Effective teaching strategies: Lessons from

research and practice (5th

ed.). Melbourne: Cengage Learning Australia, Table 3.4, p. 94.

References. Kodesia, S. 2014. Visual, Auditory and Kinesthetic (VAK) learning style model.

www.jcu.edu.au/wiledpack/modules/fsl/JCU_090460.html. Accessed 26.03.2015

Marshak, S. (2008). Earth Portrait of a Planet (3rd

ed.). Norton: New York.

Ministerial Council on Education, Employment, Training, and Youth Affairs [MCEETYA].

(2008). Melbourne Declaration on Educational Goals for young Australians. Retrieved from:

http://www.curriculum.edu.au/verve/_resources/national_declaration_on_the_educational_go

als_for_young_australians.pdf

Tasmanian Qualification Authority (TQA). (2013). Retrieved from:

https://www.tqa.tas.gov.au/

Appendix.

1.1.Reading One. (Taken from Christian, D. (2004). MAPS OF TIME: AN Introduction to

Big History. University of California Press; Berkley and Los Angeles, California).

Detailed mapping of regions where different portions of crust meet has shown that the

uppermost layer of the earth (the lithosphere) consists of a number of rigid plates, like a

cracked eggshell. There are eight large plates and seven smaller ones, as well as smaller

slivers of material. These move over a layer of softer materials just below them, the

asthenosphere, which is between 100 and 200 kilometers thick. The plates are driven by

movements in the asthenosphere and also by the pressure of materials squeezed up from even

deeper in the earth through the cracks between (and sometimes within) the plates. Like the

scum on the surface of a slow cooking soup, the more rigid material of the plates buckles,

cracks, and moves because of the currents of softer, hotter, and more malleable materials

underneath. In other words, it is the heat of the earth’s interior that provides the power needed

to move great plates of matter about the surface of the earth. That heat, in its turn, is

generated largely by radioactive materials within earth, which had been formed in the

supernova explosion that occurred just before the creation of our solar system. Here was the

geological motor that Wegener was unable to find: he could not possibly have anticipated that

the continents were being pushed around the earth by the remnant energy from a supernova

that exploded more than 4.6 billion years ago. And that takes us back, once again, to gravity,

for it was gravitational forces that first constructed and then destroyed the star that died in

that supernova explosion.

1.2.Reading Two. (Taken from Christian, D. (2004). MAPS OF TIME: AN Introduction to

Big History. University of California Press; Berkley and Los Angeles, California).

The idea that the continents really had drifted apart was given a thorough scientific basis in a

book called The Origin of Continents and Oceans, written in 1915 by a German geographer,

Alfred Wegener. Wegener assembled a huge amount of evidence suggesting that at one time

the continents had been joined together. He showed that the fit between the continents was

much more impressive it, instead of matching them at their present-day water lines, he

matched them at their continental shelves. Further, he showed that many modern-day

geological features seemed to continue from one continent to another. For example, he

described a series of rock formations, known as the Gondwana sequence, all formed,

apparently, by glacial activity. The sequence reached from the north of Africa, through to

West Africa, then to South America, through Antarctica, and into Australia. Wegener argued

that these features had been laid down as each region had moved over the South Pole. In

other words, the continents had not always been fixed in their present positions, but had, as it

were “drifted” across the surface of the earth. As a result, Wegener’s idea came to be known

as the hypothesis of continental drift.

Wegener’s evidence was impressive, but he could not explain how blocks of land the

size of Africa or Asia or the Americas could have moved across the surface of the earth.

Partly because of this, in 1928 his theory was officially rejected by the influential American

Association of Petroleum Geologists. For the next forty years, most geologists regarded his

theory as no more than an interesting hypothesis, and they looked for more conventional

explanations of the anomalies Wegener had explored. It was not until after the Second World

War that it became possible to explain how and why the continents might move across the

face of the earth. But once such an explanation was available, Wegener’s ideas became

respectable again. Indeed, with modern additions, they now form the central organizing idea

of modern geology: the theory of plate tectonics.

1.3.Reading Three. (Taken from Christian, D. (2004). MAPS OF TIME: AN Introduction to

Big History. University of California Press; Berkley and Los Angeles, California).

The modern theory of plate tectonics originated from technologies developed during the

Second World War. New forms of warfare encouraged the development of sonar to detect

submarines. But sonar also made it possible to map the seafloor more thoroughly than ever

before. As oceanographers began to examine the bottom of the Sea in detail, some strange

features emerged. One was a chain of high subterranean mountains that ran through the

center of the Atlantic and through other seas as well. At the center of these suboceanic ridges

were lines of volcanoes, from which lava seeped out onto the neighboring seabed.

In the 1960’s, starting with the work of an American geologist, Harry Hess, a

coherent explanation of all these anomalies began to emerge. Lava seeping up through cracks

that ran through most of the major ocean systems, was creating new seafloor. Such regions

are known as spreading margins. As new oceanic crust was formed, it reared up in huge

ridges of basalt, but it also acted like a wedge, driving apart seafloor that already existed. As

a result, some oceans, such as the Atlantic, appeared to be widening. Modern satellite

observations have shown that the Atlantic is getting about 3 centimeters wider every year; it’s

growing at about the same rate as our fingernails. This suggests that the Atlantic Ocean was

born about 150 million years ago, as part of what is now North America began to split away

from what is now West Eurasia.

1.4.Reading Four. (Taken from Christian, D. (2004). MAPS OF TIME: AN Introduction to

Big History. University of California Press; Berkley and Los Angeles, California).

Modern geology has built up an increasingly sophisticated picture of tectonic movements

during the past few hundred million years. These movements have been discovered largely by

studying the magnetic orientation of modern rocks whose ages are known. From this, it is

possible to estimate roughly where these rocks were when they first formed. Such studies

seem to reveal a simple pattern of dispersal and convergence. About 250 million years ago,

most continental plates were joined into a supercontinent, which Wegener has christened

“Pangaea”. It was surrounded by a single, large sea, known as Panthalassa. By about 200

million years ago, Pangaea began breaking up into two large continents. Laurasia, in the

north, contained most of modern Asian, Europe, and North America; Gondwanaland, in the

south, contained most of modern South America, Antarctica, Africa, Australia, and India.

Then, both Laurasia and Gondwanaland began to fragment. Now, we may be in early stages

of a reconvergence, as Africa and Indian move north to join Eurasia. Recent evidence

suggests that some 500 million years before the existence of Pangaea, there existed an even

earlier supercontinent, now known as Rodinia. But at present, this is as far back as we can

trace modern processes of plate tectonics.

1.5.Reading Five. (Taken from Christian, D. (2004). MAPS OF TIME: AN Introduction to

Big History. University of California Press; Berkley and Los Angeles, California).

This evidence did not mean that the was expanding, for geologists also realized that there

were areas of the earth, such as the western coast of South America, where seafloor was

being sucked back into the interior. These are known as subduction margins. Here, tectonic

plates collide, pushed together by seafloor spreading elsewhere in the world and jamming

seafloor crust up against plates of continental crust. Oceanic crust, which consists mainly of

volcanic basalts, is heavier than the granitic material that dominates the continental crust. So,

when an oceanic plate collides with a continental plate, the lighter continental plate usually

rides over the oceanic plate. The oceanic plate dives beneath the continental crust and is

eventually pulled down into the interior. (This constant recycling explains why oceanic crust

is normally so much younger than continental crust.) Slabs of descending oceanic crust grinds

against the continental plates above them as well as the material below them, creating

enormous heat and pressure. In South America, this heat, combined with the motions of both

oceanic and continental crust, generates the volcanic activity that has created the Andes.

In some areas, regions of continental crust are forced together in what are known

collision margins. The most striking example is in northern India, where the plate that

contains the Indian subcontinent has been forced up against the Asian plate. In such regions,

both plates buckle up and huge mountain ranges (here, the Himalayas) are formed. Finally,

there are regions in which plates seem to slide past each other, such as the San Andreas fault

in California. Most plate movements cause earthquakes, because the friction between plates

and the material beneath them ensures that plate movements are rarely smooth: they normally

come as sudden slippages after a prolonged buildup of pressure. So in principle it is possible

to map the edge of various tectonic plates by mapping the regions of most intense earthquake

activity.

2. Snack Tectonics Materials and Directions.

Materials:

Fruit roll ups: represents the oceanic crust, thin and dense.

Milk biscuits will replace the Graham crackers; representing the continental crust,

thick and less dense.

Frosting or whipped cream: representing the asthenosphere

Baking paper

Water

Directions:

1. Make the model

a. Give each student about a square foot of wax paper and a large dollop of

frosting. Instruct students to spread frosting into a layer about half a cm thick.

b. Tell students that the frosting in this model represents the asthenosphere, the

viscous layer on which Earth's plates ride. The plates in this model are

represented by fruit roll up (oceanic crust which is thin and dense) and graham

crackers (continental crust which is thick but less dense).

2. Divergent plate boundary

a. Instruct students to place the two squares of fruit roll up (oceanic plates) onto

the frosting right next to each other.

b. Press down slowly on the fruit roll ups (because they are dense and will sink a

bit into the asthenosphere) as you slowly push them apart about half a cm.

c. Notice how the frosting is exposed and pushed up where the plates are

separated? This is analogous to how magma comes to the surface where real

plates are moving apart at divergent plate boundaries. Most divergent plates

boundaries are located within oceanic crust. When plates begin to pull apart at

continents, rift valleys are made, like the great rift valley in Africa, which can

become the bottom of the sea floor if the plates continue to pull apart.

3. Continental-oceanic collision

a. Instruct students to remove one of the fruit roll ups from the frosting. (They

can eat it if they wish!)

b. Tell students to place one of the graham cracker halves lightly onto the

frosting asthenosphere next to the remaining fruit roll up piece. The graham

cracker represents continental crust, which is thicker and less dense than

oceanic crust (fruit roll up). It floats high on the asthenosphere so don't push it

down.

c. Gently push the continent (graham cracker) towards the ocean plate (fruit roll

up) until the two overlap and the graham cracker is on top. The oceanic plate

is subducted below the continental one.

4. Continent-continent collision

a. Tell students that they will next model what happens when tow continents

collide. Have them remove both the cracker and fruit roll up from the frosting

asthenosphere. (Students can eat or discard the fruit roll up.)

b. Place one edge of both crackers into the glass of water for just a few seconds.

c. Place the crackers onto the frosting with wet edges next to each other.

d. Slowly push the graham crackers towards each other.

e. Notice how the wet edges crumple? This is how mountains are made at

convergent plate boundaries! When continents move towards each other there

is nowhere for the rock to go but up!

5. Transform plate boundaries

a. Pick the two crackers up off the frosting and turn them around so that two dry

edges are next to each other.

b. Push one cracker past the other to simulate a transform plate boundary like the

San Andreas fault!

3. Top 10 earthquakes, tsunamis, and volcanoes.

TOP 10 Earthquakes Tsunamis Volcanoes

1 Valdivia, Chile (1960) 9.5Mag Sumatra, Indonesia (2004) Mount Vesuvius, Italy

2 Prince William Sound, Alaska (1964) 9.2Mag North Pacific Coast, Japan (2011) Krakatoa, Indonesia

3 Sumatra, Indonesia (2004) 9.1Mag Lisbon, Portugal (1755) Mount St Helens, U.S, North America

4 Sendai, Japan (2011) 9.0Mag Krakatau, Indonesia (1883) Mount Tambora, Indonesia

5 Kamchatka, Russia (1952) 9.0Mag Enshunada Sea, Japan (1498) Mauna Loa, Hawaii

6 Bio-bio, Chile (2010) 8.8Mag Nankaido, Japan (1707) Eyjafjallajokull, Iceland

7 Ecuador Coast, Ecuador (1906) 8.8Mag Sanriku, Japan (1896) Mount Pelee, Caribbean

8 Rat Island, Alaska (1965) 8.7Mag Northern Chile, Chile (1868) Thera, Greece

9 Sumatra, Indonesia (2005) 8.6Mag Ryuku Islands (1771 Nevado del Ruiz, Colombia, South America

10 Assam, Tibet (1950) 8.6Mag Ise Bay, Japan (1586) Mount Pinatubo, Philippines

4. End of Unit Test.

End of Unit Test.

Question 1.

Most geologists rejected Alfred Wegener’s idea of continental drift because:

a. they were afraid of a new idea.

b. Wegener was interested in what Earth was like millions of years ago.

c. Wegener used several different types of evidence to support his

hypothesis.

d. Wegener could not identify a force that could move the continents.

Question two.

A place where two plates slip past each other, moving in opposite directions, is known as a:

a. sliding/transform boundary

b. spreading/divergent boundary

c. colliding/convergent boundary

d. rift valley

Question three.

The geological theory that states that pieces of earth’s lithosphere are in constant, slow

motion is the theory of:

a. Subduction

b. Plate tectonics

c. Deep-ocean trenches

d. Sea-floor spreading

Question four.

Earth’s mantle is:

a. a layer of molten metal.

b. a layer of hot rock.

c. a dense ball of solid metal.

d. a layer of rock that forms Earth’s outer skin.

Question five.

Mid-ocean Ridges are:

a. found in all of Earth’s oceans.

b. found only in the Pacific Ocean.

c. located mostly along coastlines.

d. long deep-ocean trenches.

Question six.

A collision between two pieces of continental crust at a colliding/convergent

boundary produces a

a. mid-ocean ridge.

b. deep-ocean trench.

c. rift valley.

d. mountain range.

Question seven.

The process by which the ocean floor sinks beneath a deep-ocean trench and

back into the mantle is known as

a. convection.

b. continental drift

c. subduction

d. conduction

-please explain and illustrate the process.