Unit 1 Plate Tectonics

Unit 10

Plate TectonicsTable of Contents

3

4

4

Introduction

Essential Questions

Review

Lesson 10.1: Evolution of Continental Drift Hypothesis 5

Objectives Warm-up Learn about It Key Points Web Links Check Your Understanding Challenge Yourself

5 5 6

16 17 18 19

Lesson 10.2: Plate Boundaries and Geologic Landforms 20

Objective Warm-up Learn about It Key Points Web Links Check Your Understanding Challenge Yourself

20 20 21 27 27 28 30

Lesson 10.3: The Formation of Faults and Folds 31

Objective Warm-up Learn about It Key Points Web Links Check Your Understanding Challenge Yourself

31 31 32 38 39 39 41

Lesson 10.4: The Seafloor Spreading 42

Objectives Warm-up Learn about It Key Points Web Links Check Your Understanding Challenge Yourself

42 42 43 49 50 50 51

Laboratory Activity 52

Performance Task 56

Self Check 58

Key Words 58

Wrap up 60

Photo Credits 61

References 61

Copyright © 2018 Quipper Limited2

One of the breathtaking sceneries in our home planet is the majestic land formations which resulted from the movement of tectonic plates. The given picture is a rift valley at Thingvellir National Park in Iceland which was formed due to the separation of North American and Eurasian plates. This national park has been the host of diverse species of flora and fauna. Aside from the formation of geological features, the distribution of natural resources is also related to the movement of tectonic plates that affects the political and economic decisions of several countries.

Moreover, several tectonic events such as volcanic eruptions, earthquakes, and tsunamis are caused by the interaction of tectonic plates. These natural events may cause possible destruction and endanger the lives of millions of people. In fact, Philippines is expected to receive several earthquakes per year that may adversely affect cities and provinces near the center of the earthquake activity. It is therefore essential to understand the mechanism of how plates move and how geoscientists came up with these scientific theories. How did the theory of plate tectonics develop through time?


At the end of this unit, you should be able to answer the following questions. ● What are the pieces of evidence that supported continental drift hypothesis?● Why is plate tectonics theory considered as a unifying theory explaining the

known position of the continents and ocean floor?● How did seafloor spreads and what are the pieces of evidence which

supported this movement?● What are the different plate movements and its resulting landforms?● How did the movement of plates lead to the formation of faults and folds?● How do seafloor moves and its supporting evidence?

● Earth is our home planet which contains several subsystems which makes life possible. Its compositional layers include crust, mantle, and core.

● The crust is the outermost and the thinnest layer of Earth. It is composed of cold and brittle rocks. The thin oceanic crust is generally composed of a dense rock called basalt while the thick continental crust is composed mainly of granite.

● The mantle makes up 80 percent of Earth’s volume and is found underneath the crust. The lithosphere is composed of crust and uppermost mantle. The next layer is a layer of weak and plastic asthenosphere which “flows” at a very slow rate. Lastly, the lower mantle is the mesosphere.

● The innermost layer of Earth is the core which is mainly composed of iron and nickel. The outer core is said to be molten due to high temperature while the extreme pressure compressed the inner core into a solid form.


Earth is far different from what it looks like millions of years ago. The continents were once connected into one large landmass known as Pangaea. However, several processes have shaped and continue to shape the word. Have you ever wondered, how continents have drifted and what are the pieces of evidence which support this phenomena?

Let’s Connect Them All In this activity, you’ll be able to determine some of the pieces of evidence that supported that continents were once connected into a large supercontinent.

Materials: ● puzzle pieces printouts● scissors● coloring materials

Procedure: 1. Download and print the puzzle pieces from the link below.

● Wegener’s Puzzling EvidenceUS Geological Survey. 2008. ‘Fossil Evidence.’https://drive.google.com/file/d/1VgXoBFsXrMCeRJYMF7p0XWPGwjWh0An_/view?usp=sharing


https://drive.google.com/file/d/1VgXoBFsXrMCeRJYMF7p0XWPGwjWh0An_/view?usp=sharing



2. Cut out the following puzzle pieces. 3. Color the path area of the fossil areas. Please take note that you will use a

different color coding for each fossil: yellow for Glossopteris; green for European Flora: red for Mesosaurus: blue for Cynognathus, orange for Lystrosaurus.

4. Connect each puzzle pieces to form the complete picture. 5. Answer the given guide questions.

Guide Questions:

1. How can the fossil records be utilized to determine history of continental plates?

2. What does this activity suggest regarding the position of the landmass millions of years ago? Cite evidence to support your answer.

During the early times, the prior knowledge of most geologists is that all continents and ocean basins are in fixed position. However, less than a decade after the 1960s, this idea was changed due to technological advances which led to the discovery that Earth’s continents are gradually moving resulting to the collision of continental blocks, splitting apart of landmasses, and continuous creation and destruction of oceanic basins. The Birth of Continental Drift Hypothesis The scientific revolution, which involved the shift in the conception of the position and movement of continents, started in the early 20th century as a proposal called continental drift hypothesis. Nevertheless, this idea was not readily accepted because of some scientific concerns. For more than 50 years, the idea of moving continents is rejected by the scientific community. The continental drift hypothesis was proposed by German meteorologist named Alfred Wegener. In 1915, he wrote The Origin of Continents and Oceans

Copyright © 2018 Quipper Limited 6

that contains the continental drift hypothesis.

Fig. 2. The breakup of Pangaea.

This idea was believed to be a product of Wegener’s observation during his expedition in Greenland where he observed the breakup of ice in the sea. Continental drift hypothesis states that all known landmasses on Earth were once joined in one supercontinent known as Pangaea (meaning “all- lands”). It is surrounded by a huge ocean known as Panthalassa. Wegener added that this supercontinent began to break into smaller landmasses about 200 million years ago which is composed of Laurasia and Gondwanaland. The northern


supercontinent was the Laurasia which is the origin of North America and Eurasia except India. On the other hand, the southern supercontinent was Gondwanaland was previously composed of South America, Africa, Australia, India, and Antarctica. Through time, Laurasia and Gondwanaland broke into smaller landmasses which gradually drifted to their present positions in a span of millions of years.

Evidence Supporting the Continental Drift Hypothesis Wegener along with those people who supported his hypothesis collected and presented several pieces of evidence to prove their idea. These pieces of evidence are as follows:. Continental Fit Even before Wegener’s hypothesis, several people already noticed that some continents remarkably fit especially Africa and South America. Wegener noticed this pattern on the coastlines of opposite sides of the Atlantic Ocean. His claim was challenged by other scientists because he used the present-day coastlines which are regularly changed by erosional and depositional processes. Scientists later on determined that the use of the seaward edge of the continental shelf as a continent’s boundary are the better way to estimate the fit between continents.

Fossil Evidence Wegener’s pursuit of evidence for the continental drift hypothesis was strengthened when he learned that similar fossil remains of organisms were found from both South America and Africa. He thinks that there was some sort of land connection needed to explain the similarity of life forms in widely separated continents. To prove his point, he recorded cases wherein fossil organisms were found in a separate landmass. These fossils included Glossopteris, European flora, Mesosaurus, Lystrosaurus, and Cynognathus. Alfred Wegener cited the presence of “seed fern” fossils known as Glossopteris in Africa, Australia, India, South America, and was later on recorded in Antarctica. Glossopteris contains large seeds and leaves, hence, its impossible that it could be


carried by wind to different continent that is greatly separated from one another. In addition, fossils of European flora was found to exist millions of years ago were found outside the European continent..

Mesosaurus is an aquatic fish-catching reptile found in black shales from eastern South America and southwestern Africa was dated to be about 260 million years old. According to Wegener, this is one of the confirmations that South America and Africa were once part of a large landmass. Moreover, Lystrosaurus a mammal-like herbivorous land-dwelling reptile was found in Africa, India, and Antarctica. Lastly, Cynognathus, an advanced therapsid which is mammal-like land reptile was also found in South America and Africa. These evidence further support the claim that current continents were once part of a bigger land mass.

Fig. 4. Evidence of matching fossils

Similarity of Rock Types and Mountain Ranges. Another evidence that Wegener found is the presence of 2.2-billion-year-old igneous rocks in Brazil that is similar to the rocks found in Africa. Also, the characteristics of rocks in Appalachians mountain range in North America are similar with some of mountains found in Alps mountain range in Europe including mountains in the British Isles and Caledonian mountains in Scandinavia. Interestingly, these mountains could form a continuous mountain belt.


Fig. 5. Evidence of similar rock types and features

In line with this, Alexander du Toit, South African geologist, further supported the hypothesis of Wegener through additional geological evidence. He joined together the landmasses comprising Gondwanaland and found similarities among Andes mountain range in South America and mountains of South Africa, Antarctica, and Australia. He thinks that these mountain ranges were once part of a bigger structure in Gondwanaland and named it as Samfrau mountain belt.

Glacial Evidence Wegener learned that there was evidence showing the presence of a glacial period dated about 300 million years ago in South Africa, South America, Australia, and India. This was indicated by the presence of glacial striation and tillites. It means that during that time, ice sheets cover huge areas in Southern Hemisphere. Most of the areas found to have glaciation in the past were located in subtropical or tropical climates today.


Additionally, fossils of coal seams were found in Antarctica yet this fossil could only exist in tropical regions. This suggests that Antarctica was once located near the tropics.

Wegener’s proposal encountered a great deal of open criticism especially when his book was translated into other languages. His inability to identify a credible mechanism for how continents move is one of the main flaws that resulted in these criticisms. Wegener suggested that the drifting of the continents was an effect of the tidal force. This idea was opposed by Harold Jeffreys because the force needed to displace the continents through this mechanism is enough to affect or even stop Earth’s rotation after a few years. In addition, Wegener also incorrectly explained that larger and sturdier continents broke through thinner oceanic crust, but there was no scientific evidence that this is possible. In addition, it also violated the principles of rock strengths which is a well-known concept that time. Wegener’s hypothesis is not enough to change the established scientific views during his time as it contains several incorrect concepts.

In the emergence of modern instruments after World War II and with the cooperation of different researches and geoscientists, information about the features and tectonic activities in the sea floor gradually emerged. In 1962, Harry Hess proposed the seafloor spreading hypothesis which suggested that the seafloor is moving away from the ridge which is driven by mantle convection. There is a separate lesson which discusses this hypothesis in detail.

Plate Tectonics Theory The advances in instruments, as well as the ocean exploration, a more comprehensive explanation of the movement of continent and ocean floor, which is now known as the theory of plate tectonics was conceived. According to plate tectonics theory, the lithosphere (includes the uppermost mantle and the overlying crust) behaves as a strong, rigid layer which is broken into segments known as plates. The lithosphere is thinnest in the ocean which varies from a few kilometers and may reach up to 100 kilometers. On the other hand, the lithosphere found in continents is generally thicker than 100 kilometers and may even reach up to 200-300 kilometers in depth. Underlying the lithosphere is a weak region in the mantle known as the asthenosphere wherein the rocks are found to be very near the melting point thus making the layer ductile and highly viscous. This characteristic of the asthenosphere permits the lithosphere above to move as a separate component.


Fig. 7. Lithospheric plates.

The lithosphere is broken into several irregularly-shaped segments called lithospheric plates or tectonic plates that are in constant motion with respect to each other. Although there are about two dozen lithospheric plates, there are only seven major plates which include North America, South American, Pacific, African, Eurasian, Australian-Indian, and Antarctic plates. There are also intermediate-sized plates which include the Caribbean, Nazca, Philippine, Arabian, Cocos, Scotia, and Juan de Fuca plates. It is important to note that these plates also includes the ocean floor and is not only limited to continental boundaries.

Although the evidence for the continental drift hypothesis are compelling, it is still recognized and supported by other scientists. As mentioned before, Wegener’s hypothesis was opposed due to the presence of scientifically incorrect concepts. The proposal of a new scientific model about Earth, which is theory of plate tectonics, provided a more detailed explanation of numerous geological events and the creation of geological formations. The following paragraphs describe the pieces of evidence supporting plate tectonics theory.


Evidence Supporting the Plate Tectonic Theory Ocean Drilling The Deep Sea Drilling Project, which operated from 1968 to 1983, was used to collect data from the seafloor to establish its age. This was spearheaded by Maurice Ewing together with Bruce Heezen and Marie Tharp. They mapped the ocean floor where they found the presence of oceanic ridge and other features of the ocean topography. The data obtained from the Deep Sea Drilling project showed that the ocean floor increases in age as it moved farther away from the ridge crest which supports the seafloor spreading hypothesis.

Hotspots Radiometric dating of the Hawaiian Island-Emperor Seamount chain proves that volcanoes increase in age as they move away from the hot spot. A hot spot is an area of volcanism, high heat flow, and crustal uplifting caused by the upwelling of hot rock known as mantle plume. The case of volcanic chains formed in Hawaiian is one of the compelling evidence that the plates are moving. As the Pacific plate moved over the hotspot, a chain of volcanic structures was formed which also reflects how much time has passed since it was situated above the mantle plume.

Paleomagnetism It is the study of magnetism of ancient rocks. Magnetite is a naturally-occurring magnetic mineral which is rich in iron and commonly found in basaltic lava flows. These magnetite grains are initially nonmagnetic caused by the extreme temperature of lavas once it erupted at the surface. However, once it cooled down and reached about 580°C, the grains become magnetized and align themselves based on Earth’s current magnetic field. This magnetism remains as the lava starts to solidify and can be used to identify the position of the magnetic poles at the time of their formation. Several paleomagnetic data were collected in rocks to determine the direction of the magnetic poles at a specific time.


Apparent Polar Wandering Data from paleomagnetism of rocks in Europe and North America showed that there was an apparent change in position of magnetic poles over time. Based on Figure 8, it can be observed that for the past 500 million years the magnetic pole in North America and Eurasia seems to change its position. Nevertheless, it is impossible that there is a varying magnetic pole in each continent. Rather, there is a fixed position of the magnetic pole and the continents together with the magnetized rocks are those that move. Plates move in an average of a few centimeters per year which can be compared to the growth of human fingernail.

Fig. 9. Apparent polar wandering.

Mechanism of Plate Motion There are different forces which drive the motion of tectonic plates. Remember in the past units that although the mantle is composed of solid rock, it is hot, ductile, and weak making it capable of fluid-like behavior making it possible to facilitate convection. Mantle convection is driven by a combination of three thermal processes: (1) heating at the bottom caused by the heat loss from Earth’s core; (2) heating due to radioactive decay and; (3) cooling on the surface creating thick, cold lithospheric slabs denser than the mantle. There are two models of plate-mantle convection proposed to explain the mechanism of plate motion.

Some researchers proposed that the mantle is divided into two zones of convection which is a thin layer in the upper mantle at a depth of 660 kilometers and a thick layer located below. This model is known as “layer cake” model.


Fig. 10. “Layer cake” convection model.

Other researchers support the whole mantle convection where denser oceanic lithosphere sinks and may even reach the core-mantle boundary. This material eventually melts and rises toward the surface of Earth.

Fig. 11. Whole mantle convection model

Aside from this heat-driven in the movement of plates, some geologists also believe that there are also gravity-driven mechanisms referred to as “slab-pull” and “ridge-push” (shown in Fig. 12). It is important to note that these mechanisms go hand in hand and even if it is governed by gravity, it still depends on the


temperature differences of Earth’s interior.

Fig. 12. Slab-pull and ridge-push mechanisms

Ridge push is the force that causes warm and less dense material to force itself up through a ridge. On the other hand, slab-pull is a pulling force which causes the oceanic plates to move downward at subduction zones due to difference in density as well as the effect of gravity. These models are still being developed and may still be improved to further explain the mechanism but the concept which states that the plate-mantle motion is caused by a type of thermal convection caused by the unequal distribution of heat within Earth is a generally accepted fact.

● Alfred Wegener proposed the continental drift using several evidences such as similar fossils, coastline fit, similar rock types, and glacial evidence.

● Continental drift hypothesis proposed that known landmasses were once joined in one supercontinent known as Pangaea (meaning “all- lands”) and


began to break into smaller landmasses about 200 million years ago. ● Seafloor spreading hypothesis suggested that seafloor is moving away

from the ridge which is driven by mantle convection.● Plate tectonics combines the idea of the continental drift and seafloor

spreading, stating that Earth is divided into several lithospheric plates that move relative to each other. It is supported by data obtained from ocean drilling project, paleomagnetism, and apparent polar wandering.

● Mantle convection is the rising of warm material and sinking of cold material in the mante. There are two models of mantle known as layer cake model and whole mantle convection

● Gravity-driven mechanism includes slab pull and ridge push. Slab pull is the force which causes the oceanic plates to move downward at subduction zones. Meanwhile, ridge push is the force that causes warm and less dense material to force itself up through a ridge.

For further information, you can check the following web links:

● If you want to watch a video about Pangaea then you can use this link.Molna M. 2014. ‘The Pangaea Pop-Up.’https://www.youtube.com/watch?v=p-vNSqUy0l4

● Are you curious about the scientific journey of Alfred Wegener?The New York Times. 2015. ‘Animated Life: Pangea | Op-Docs.’https://www.youtube.com/watch?v=mRqjo-N_TDU


https://www.youtube.com/watch?v=p-vNSqUy0l4

https://www.youtube.com/watch?v=mRqjo-N_TDU

https://www.youtube.com/watch?v=mRqjo-N_TDU

A. Identify which among the given set of words does not below to the group. Encircle the word your choice. Then provide 1 to 2 sentences to explain your choice.

No. A B C

1 Cynognathus Mesosaurus Glossopteris

2 Tethys Laurasia Gondwanaland

3 Arabia Africa Antarctic

4 ancient climate magnetic reversal geologic fit

5 ocean drilling hotspot fossil evidence

6 Pacific Nazca Cocos

7 convection slab pull ridge push

8 Alexander du Toit Harold Jeffreys Alfred Wegener

9 layer cake whole mantle subduction

10 rock similarity paleomagnetism hotspot

B. Identify which term is described in each statement.1. It is the mineral found in lava which helps in mapping magnetic orientation

of the ocean seafloor.2. This proposes that the mantle is composed of a thick and thin convection

layer.3. It is the theory which states that the lithosphere is broken into smaller

fragments.4. It is the upwelling of extremely hot molten material from the mantle.5. This pair continents fit together like in jigsaw puzzle.6. This evidence explains that the area in the polar region where initially

found in the tropical region.


7. It is the ocean that surrounded Pangea.8. The fossil of this aquatic fish-catching reptile was used to support the

continental drift hypothesis,9. This area has an active hotspot which is also the reason for the existence of

numerous volcanoes in this place10. It is the pulling force which causes the oceanic plates to move downward

at subduction zones due to difference in density as well as the effect of gravity.

Answer the following question using 3-4 sentence. 1. How did the continents drift?2. What were the pieces of evidences proposed by Wegener? why did the

scientific community debunk the continental drift hypothesis proposed by Wegener?

3. What is the difference between plate tectonics and tectonic plate?4. Why is plate tectonics theory considered a unifying theory in Geology?5. Refer to the accompanying map and answer the following.

a. What are the tectonic plates that covered mostly by continental crust?b. What are the tectonic plates covered mostly by ocean?


Mountains, volcanoes, rift valleys, and trenches depict some of the sceneries in our dearest home planet. Interestingly, each of this geologic features has a story to tell regarding the different processes that shape its formation. Just like human, we are what and who we are today because of the different circumstances which shape our life. In view of the lens of geology, how can plate movement be able to form various geological land formations?

Plate Movement Crossword Material:

● word search about plate movement

T Y Y U W D I Z A T N M E X N K B I R P E G F A U L T A H S G S X G B R N U Q B R O T Y F S M L Q X E W B R F W Q Q T F V R P O G O N F A K N G R Q D U I T I S O M G U P R Y X S M C T N E G R E V I D


Procedure:

1. Find a partner. You will change turns on searching words in the box shown below. Each person will only be given one minute per turn to search for words. If the first player cannot search a word for a minute, that certain player will lose a turn.

2. Look for the following terms in the box: rift, transform, divergent, convergent, fault. Each word corresponds to one point.

3. The player who will get three points first will win the game. Guide Question:

1. Based on your prior conception, what is the description of each term in the box?

Plates are in constant motion relative to each other, and most major tectonic activities can be found in plate boundaries. Additionally, several geological formations are produced along these boundaries such as mountains, volcanoes, rift valleys, ridges, and trenches. There are three types of plate boundaries categorized by the kind of movement it demonstrates. Types of Plate Boundaries Divergent Plate Boundaries Divergent boundaries are formed when two plates move away from each other resulting in the rising of the molten material. This type of boundary is also known as constructive margins because new ocean seafloor is created during the processes. This type of boundary is associated with spreading


centers because this is where the spreading of the ocean floor happens. Molten material from the mantle rises from the ridge then fills up the space created by the spreading plates thus anew crust is formed. Aside from the formation of oceanic ridge and seafloor, this type of boundary could create continental rift or rift valley which is an elongated depression that can either form on land or on under the sea. There are several processes involve in the formation of continental rift or rift valley.

Fig. 14. Birth of an ocean floor.


Strong upwelling of magma causes uplift and doming in the area. The central block collapses inwardly then crack and continuously expand at the surface. At this point, the crust starts to separate into two pieces. There are instances where rivers may form in the depression, but the main drainage continues to move away from the uplifted area. As the two plates diverge, the process leaves space for the upwelling of basaltic magma. As more cracks are formed, more magma upwells and floods in the rift valley floor. Spreading continues as more basaltic magma extruded in the mid-oceanic centerline. This area is relatively hotter and more buoyant than the other parts of the ocean creating elevated ridges along the spreading centers. As the oceanic crust moves away from the spreading center, it becomes older, cooler and denser. The older oceanic crust is recycled in oceanic trenches. This process continues and only stops when a new ocean is opened in another divergent boundary forcing the old one to close.

One of the examples of the landforms as a product of a divergent boundary is the formation of Atlantic Ocean. It was formed from the separation of the African and American continents. Meanwhile, Red Sea is continuously widening because of constant divergence of Arabian plate and Nubian plate. On the other hand, East African Rift valley is formed due to the splitting of African plate into Somalian plate and Nubian plate.

East African Rift Valley Atlantic Ocean Red Sea

Fig. 15. The East African Rift Valley, Atlantic Ocean, and Red Sea are products of divergent boundaries.


Convergent Plate Boundaries Convergent boundaries are formed when two plates move toward each other. This is also known as destructive margins since the processes involved in this plate motion generally destroy crust. Moreover, this type of boundary is also called subduction zone which is an area where denser lithospheric plate descends into the mantle. It is a consequence of rifting and formation of new oceanic floors in other parts of the world. Continental lithosphere is less dense making it more buoyant compared to oceanic lithosphere which sinks to greater depth.

There are three types of plate convergence, namely: oceanic-continental convergence oceanic-oceanic convergence, and continental-continental convergence. Subduction zones are formed during oceanic-continental convergence oceanic-oceanic convergence. The occurrence of earthquakes and volcanic mountain ranges mark the path of the descending plate as it sinks below the other plate. The location where most seismic activities occur during subduction is called as Wadati-Benioff zone. Moreover, the surface manifestations of convergent boundaries are deep-ocean trenches which are often remarkably long and deep formations that is mainly caused by the subducting oceanic lithosphere in the mantle.

In oceanic-continental convergence, the continental crust remains buoyant while the oceanic crust starts to sink into the mantle. The process forms continental volcanic arc such as the Andes Mountain range.

Fig. 16. Oceanic-continental convergence.

On the other hand, when two oceanic crusts converge, the denser oceanic crust sinks beneath the other oceanic crust then creates a volcanic island arc such as the


island of Japan. This is called an oceanic-oceanic convergence.

Fig. 17. Oceanic-oceanic convergence.

Lastly, the third type of convergence happens when a continental crust moves toward another landmass. This is called a continental-continental convergence. Aside from the sediments of the continental crust, the seafloor sediments that comprised the old oceanic crust where the were trapped between the closing continents. Together, these sediments are folded into linear belts, metamorphosed and pushed upward to form mountain ranges.

Fig. 18. Continental-continental convergence.

When Pangaea broke up, India became part of the southern continent called Gondwanaland which also started to split. About 145 million years ago, India began moving towards Eurasia and reduced the size of Tethys Sea. As India approached Eurasia, the seafloor subducted beneath the continental crust of the latter. Volcanoes started to form along the edge of the plate where a nearby trench is


located. When all of the remnants of Tethys Sea already descended, India started to be pushed against the Eurasian plate. Seafloor sediments trapped between the continents are compressed and pushed upward to form the Himalayas mountain range.

Folding and uplifting continues until today. Sedimentary rocks are also turned into metamorphic rocks because of the extreme compression happening. As India cannot subduct below Eurasia, this process of collision will eventually stop.

Transform Plate Boundaries Transform plate boundaries (also transform fault boundaries) happen when two plates simply slide horizontally past each other. This is also known as conservative margins since there is neither destruction nor formation of new lithosphere. Along with this boundary, fault zone is created which is composed of fractures on Earth’s surface produced due to appreciable movement of rock layers. One of its examples is the San Andreas Fault which is formed due to the interaction of Pacific Plate and North American Plate.

Fig. 19. Transform plate boundary.


● There are three different plate boundaries namely: divergent boundary, convergent boundary and transform fault boundary

● Divergent boundary is formed when two plates move apart. This is also known as constructive margins.Rift, ridge, and new seafloor are the land formations created from plate divergence.

● Convergent boundary is formed when two plates move toward each other. This is also known as destructive margins. Mountains, island arc, and volcanic arc are formed due to the convergence of plate.

● Transform plate boundary happens when two plates simply slide horizontally past each other. Fault zones are formed in transform plate boundary.


● This link could be used as a supplementary material about plate movement.

IRIS Earthquake Science.2016.’Plate Boundaries & Tectonic plates (Educational)’ https://www.youtube.com/watch?v=Xzpk9110Lyw

● Have you ever wondered, how Philippines was formed in the context of plate boundary? You can read the information in this link.

Vokaty, M. 2014.’The Philippine Sea Plate.’ https://tectonicsofasia.weebly.com/philippine-sea-plate.html


https://www.youtube.com/watch?v=Xzpk9110Lyw

https://www.youtube.com/channel/UCo7diqNFmYbm8nrVUEPtTsQ

https://www.youtube.com/channel/UCo7diqNFmYbm8nrVUEPtTsQ

https://tectonicsofasia.weebly.com/philippine-sea-plate.html

https://tectonicsofasia.weebly.com/philippine-sea-plate.html

A. Identify which plate movement leads to the formation of the certain geologic feature or event. Use the choices given below.

1. It can cause the formation of fault line system. 2. It is also known as constructive margin. 3. It could be associated with the presence of Wadati-Benioff zone. 4. This plate movement creates new seafloor. 5. It can create trenches. 6. This plate movement created Himalayas. 7. It is associated with strong and shallow earthquake 8. This plate interaction creates volcanic arc. 9. It results to the formation of mountain range.

10. This causes the formation of rift valley.


B. Write true if the statement is correct while write false if the statement is incorrect.

1. A new seafloor is created when molten material from the lowermost crust rises and fills up the gap formed due to divergence of plate

2. Younger oceanic crust is found along the oceanic ridge.3. The collision between oceanic and continental crust forms continental

volcanic arc4. San Andreas fault is formed due to two plates passing slide each other.5. Slab pull could most likely be observed at transform boundary.

C. Determine the word described in each item in order to accomplish the crossword puzzle.

Down 1. This plate movement is associated with the area where spreading of ocean

floor occurs.2. It is an elongated depression formed when plates move away from each

other.3. The difference in ____________ causes one plate to subduct to another plate.

Across 4. This is kind of margin is associated with transform boundary.5. It is a long and deep area at subduction zone.


Answer the following question using 3-4 sentences.1. How do rift valleys form?2. Are trenches always formed during convergence of plates? Briefly explain

your answer.3. Which geologic event would most likely occur in all types of boundary?4. Are all mountains formed due to convergence of plates?5. Why is transform boundary called as conservative margin? Why do you think

is transform plate boundary is named in that way? What is being transformed during the process?


Stress can be viewed in several contexts. In human, stress is the state of where a person experiences pressure which can either make or break personality of an individual. Similarly, stress, in the context of geology, is the force exerted to rocks which can cause rock deformation. Have you ever wondered, what are the different process which applies stress on rocks? How are folds and faults formed?

The Faults in Our Country In this activity, you’ll be able to identify the faults found in the Philippines

Materials: ● map of distribution of active faults and trenches in the Philippines● map of the West Valley Fault System

Procedure: 1. Download the map of distribution of active faults and trenches in the

Philippines.

● Distribution of Active Faults and Trenches in thePhilippinesPhilippine Atmospheric, Geophysical and Astronomical ServicesAdministration. 2000. ‘Distribution of Active Faults and Trenches in thePhilippines.’http://www.phivolcs.dost.gov.ph/images/active.faults/af_trench_with_capitals.pdf


http://www.phivolcs.dost.gov.ph/images/active.faults/af_trench_with_capitals.pdf



2. Using the map of the West Valley Fault System, identify three faults located in

Luzon, Visayas, and Mindanao. Record it on the table provided.

● 2015 PHIVOLCS West Valley Fault Line Google Map Philippine Institute of Volcanology and Seismology. 2015. ‘2015 PHIVOLCS West Valley Fault Line Google Map.’ https://www.google.com/maps/d/viewer?mid=1ju40GKMX7aDHuPigs3ottK2Smac&hl=en_US&ll=14.56653196631963%2C121.0853360976563&z=8

Guide Questions:

1. What are the three faults located in Luzon, Visayas, and Mindanao? Write your answer on the table provided.

Area Faults

Luzon

Visayas

Mindanao

2. Based on the given map of West Valley Fault System, what are the provinces

which will be affected by the “Big One” earthquake? 3. The province of Batangas experienced an earthquake swarm on April 2017.

This involves successive earthquake occurrences in a given period of time. Nevertheless, PHIVOLCS clarified that this did is not related with the “Big One” earthquake. What could be the possible fault related to the earthquake in Batangas? Use the map of distribution of active faults and trenches in the Philippines.

The constant movements of tectonic plates continue to shape Earth’s structure. When rocks are subjected to stress, it responds by flowing, bending or breaking depending on the type of material and the amount of stress it experiences. Eventually, these events lead to folding and faulting of rocks.


https://www.google.com/maps/d/viewer?mid=1ju40GKMX7aDHuPigs3ottK2Smac&hl=en_US&ll=14.56653196631963%2C121.0853360976563&z=8



Types of Stress Stress is a force exerted on an object, in this case, a rock. There are two general types of stress. Confining stress takes place when a rock or sediment is buried and acts uniformly in all direction. The pressure builds up as materials are piled above a certain layer of rock. In fact, confining stress is related to burial metamorphism. On the other hand, directed stress only acts in one direction and is most likely associated with tectonic activities. There are three types of directed stress, namely: compressive, tensional, and shear stress.

Compressive stress squeezes and shortens the layer of rock. It usually happens at convergent boundary. Meanwhile, extensional or tensional stress causes rocks to be pulled apart which fractures and lengthens the layer of rock. It usually occurs at divergent boundary. On the other hand, shear stress acts in parallel but opposite direction. This type of stress causes one rocks to slide past another as seen in transform fault boundary.

Fig. 20. Different kinds of stress

Stress produces the deformation known as strain. There are several factors which could influence rock deformation. The nature of the material affects how a rock behaves when stress is applied. Meanwhile, the higher the temperature, the more likely it is for the rocks to deform. Moreover, pressure also affects the behavior of rocks under stress wherein as pressure is added then the more likely a given rock could be deformed. Lastly, stress applied over a long period of time in a slow yet constant manner could eventually lead to rock deformation.


Types of Rock Deformation There are three types of rock deformation, and these include elastic deformation, ductile deformation, and brittle deformation. A rock undergoing elastic deformation goes back to its original size and shape once the stress is removed. Ductile deformation, on the other hand, is a condition where moves in plastic manner that could lead to permanent change in shape and size yet do not involve breakage of rock. This deformation occur at area which has high pressure and high temperature. Lastly, brittle deformation occurs when rocks surpassed its elastic limit leading formation of fractures. It occurs at low pressure and low temperature conditions.

Ductile deformation is associated with folding of rocks. The series of wave-like ripples or bends formed during mountain building are called folds. Some folds are composed of several hundreds of meters layers of rocks bent and deformed while others are only present in a microscopic scale. In general, most folds are products of compressional stresses. Folding shortens the horizontal distance in rocks, and it usually occurs as a repeating pattern.

Folds: General Characteristics and its Parts A fold is composed of various parts. A fold arching upward is called an anticline while one arching downward is a syncline. Limbs are the sides of the fold. The imaginary plane symmetrically separating the fold into two is called the axial plane. The fold axis is the line dividing the fold into its two limbs, and it passes through either the crest or the trough of the fold.

Fig. 21. Parts of a fold


Folds can be symmetrical or asymmetrical. Additionally, overfolds are folds that inclined in an overturned manner. Meanwhile, recumbent folds are those tilted beyond the vertical axis in which the folds are already parallel to the horizontal plane. On the other hand, if the fold has only one limb, it is categorized as a monocline.

Fig. 22. Different types of folds

Folding of rocks could also result in other land formation. A circular or an elliptical anticlinal structure known as dome can also be formed. It usually looks like an inverted bowl. On the other hand, basin is an synclinal structure which is the inverse of a dome.

Fig. 23. Dome and basin

In geology, an upward-arched anticline is used only if the oldest rocks are in the center and the youngest are on the outside of the fold. However, if the ages of the rocks are unknown, an upward-arched form is called antiform which is also similar to anticline. Syncline is only used to describe downward-arched fold when the


youngest rock is located at the center. Otherwise, if the rock ages are unidentified, the downward arch is termed as synform. Faults: General Characteristics and its Parts Some rocks eventually break or fracture in response to the stress whereas this process involves brittle deformation. A fault is a fracture or a discernible displacement where rocks grind or slide past each other. Movement along a fault can be gradual or sudden and may create large magnitude earthquakes. It is also possible that a fault can be a single fracture in a rock or can be composed of a series of fractures called fault zones. Parts of Fault There are two parts of a fault. A fault line is the trace of fracture on rocks while fault blocks are those that interact during faulting of rock layers which can either be hanging wall or footwall. The overlying side of the fault is called the hanging wall and is named as such because miners noticed that it is usually the side that hung over their heads. The side beneath the fault and most of the time where the miners walked is called footwall. Types of Fault There are several types of faults. A dip-slip fault involves the upward and downward of fault blocks which either be normal or reverse fault.

Fig. 24. Types of fault

A normal fault is where the hanging wall moves down relative to the footwall. It is


a product of tension which pulls Earth’s crust apart. Graben is formed when a wedge-shaped block of rock dropped downward between a pair of normal faults. Meanwhile, horst the uplifted block or rock situated between a pair of normal faults.

In a reverse fault, the hanging wall moves up relative to the footwall. It a product of compression and therefore shortens the structure. A special type of reverse fault is known as the thrust fault that causes nearly horizontal movement due to its low angle of inclination which is less than 45.

A strike-slip fault occurs when the blocks of rocks move horizontally past each other. This is a product of shear stress and usually present in transform plate boundary. This can either be left strike-slip fault and right strike-slip fault depending on the direction of movement of a block of rock with reference to another block of rock.

The oblique fault has both a dip-slip fault and strike-slip fault. This implies that it involves significant horizontal and vertical movements.

Furthermore, a joint is also fracture in a rock, but unlike faults, joints do not produce discernable displacements. One of its examples is the Jurassic limestone layer which is found in Southwestern England.

Fig. 25. Jurassic limestone layer containing joints.


Joints, fractures, and faults are essential for geoscientists. Aside from it being planes of weaknesses and should be considered when building structures, faults are also areas where hydrothermal solutions precipitate to form rich-ore veins.

● Stress is a force exerted on an object, in this case, a rock. The different types

of stress include confining stress and directed stress, which is further subdivided into tensional, compressional, and shear stress.

● Rock deformation involves changes shape and/or size which can either be permanent or temporary. The different types rock deformation include elastic, brittle, and ductile deformation.

● Folds are series of wavelike ripples or bends which is mostly formed when rock layer is subjected to compressive stress. It is composed of upward fold known as anticline while downward fold as syncline.

● Fault is a fracture or a discernible displacement where rocks grind or slide past each other. This different types of faults include normal dip-slip fault, reverse dip-slip fault, strike-slip fault, and oblique fault

● Joint is also fractured in a rock, but unlike faults, joints do not produce discernable displacements.


For further readings, you can check the following web links:

● PHIVOLCS released several platforms which aim to increase the awareness of people about the Big One earthquake as well as the faults found at a given place. This website is entitled “Fault Finder”. This can locate nearest fault found in a given area.

Phivolcs. N.d. ‘Fault Finder.’ http://faultfinder.phivolcs.dost.gov.ph

● Are you still curious about folds? You can check these links. National Geographic. 2018. ‘Fold Mountain.’ https://www.nationalgeographic.org/encyclopedia/fold-mountain/

● The government also funded an project on developing an atlas about the valley fault system. You can check this link.

Phivolcs-DOST. 2015. ‘The Valley Fault System.’ http://www.phivolcs.dost.gov.ph/images/VFS-Atlas/index.html

A. Write true if the statement is correct. Meanwhile, if the statement is incorrect then change the underlined word or phrases in order to make the statement correct. 1. The downward bending of rock is known as dip-slip fault. 2. An area which is contains several closely positioned faults is called a fault

zone. 3. The block of rock which has a wider bottom as compared to its upper part

is referred as the hanging wall. 4. As materials are stacked on top of a rock layer, this layer experiences

confined pressure that could eventually cause its deformation. 5. Rocks are subjected to compressive stress along subduction zone. 6. Time, temperature, pressure, and volume are some of the factors affecting

the deformation of rocks.


http://faultfinder.phivolcs.dost.gov.ph/

http://faultfinder.phivolcs.dost.gov.ph/

https://www.nationalgeographic.org/encyclopedia/fold-mountain/

https://www.nationalgeographic.org/encyclopedia/fold-mountain/

http://www.phivolcs.dost.gov.ph/images/VFS-Atlas/index.html

http://www.phivolcs.dost.gov.ph/images/VFS-Atlas/index.html

7. Synclines lead to the formation of domes.8. Asymmetric folds are formed when it tilted beyond the perpendicular.9. Graben is the downward block located along the fault zone.

10. Normal dip-slip fault is most likely associated to divergent plate movement.11. The fracture on rock layers which contains minimal displacement is known

as joint.12. Compressional stress causes folding of rock layers.13. Normal and reverse fault involves vertical displacement.14. Rocks along strike slip fault experience tensional stress.15. Area with high temperature and high pressure could lead to folding of rock

layers.

B. Identify the term described in each statement then find the term in the word hunt.1. This kind of stress are found at spreading center.2. This are cracks on the surface produced by appreciable movement of rocks.3. It is a wave-like formation which resulted from collision of plates.4. It is the deformation produced when stress is applied to rocks.5. It is the point of reference in folds which is used to determine whether a

given formation is symmetric or not.


Answer the following question using 3-4 sentence.1. What is the difference of the three main types of fault in terms of movement

and associated stress?2. How does folding occur? What are the conditions needed for the occurrence

process?3. Why are older rock layers found at the center of the basin?4. How do plate movements generate faults?5. Can you create fault models? Make 3D models of the different types of fault.

● Seven Paper Models that Describe Faulting in the EarthTau Rho Alpha and John C. Lahr. 2017. Seven Paper Models that DescribeFaulting in the Earth.’https://geomaps.wr.usgs.gov/parks/deform/7modelsa.html


https://geomaps.wr.usgs.gov/parks/deform/7modelsa.html

https://geomaps.wr.usgs.gov/parks/deform/7modelsa.html

The ocean topography contains various land formation almost similar to those found at the center. Interestingly, continents are not only those that are in constant motion in which seafloor is also constantly moves in lateral manner. Why seafloor spreads and what are the pieces of evidence that such motion really occur?

Let The Seafloor Spread In this activity, you’ll be able to simulate the spreading of seafloor.

Materials: ● seafloor spreading sheet template A, and B● scissors● clear tape● coloring materials

Procedure: 1. Download the needed file from this link.

● A Model of Seafloor SpreadingTroup Country School System. n.d.. ‘A Model of Seafloor Spreadingl.’http://www.troup.org/userfiles/929/My%20Files/Science/MS%20Science/6th%20Science/Geology/geological_events/model_seafloor_spreading_all.pdf?id=21566


http://www.troup.org/userfiles/929/My%20Files/Science/MS%20Science/6th%20Science/Geology/geological_events/model_seafloor_spreading_all.pdf?id=21566




2. Get the Seafloor Spreading Sheet Template A. Cut the three vertical lines. Be careful not cut further than the vertical lines.

3. Secure the slit by placing tape over each slit then recut the slit through the tape.

4. Obtain Seafloor Spreading Sheet Template B. Color every other strip using yellow, orange, and red.

5. Cut the Seafloor Spreading Sheet Template B into half. Be sure to use the dash line as the guide.

6. Insert one end of one of the strips of paper through middle and left end vertical line. Do the same to the the sheet but this time in the right end vertical line.

Guide Questions: 1. What did Seafloor Spreading Sheet Template B represent? 2. What is the part of the seafloor which corresponds to the middle and end sli?

What event occurs at this located? 3. What is the part of the seafloor which corresponds to the end slits? What

event occurs at this located? 4. Supposed that you’ll get rock samples near the middle slit and the end slits,

what can you infer about the age difference of this sample? Is it older or younger?

5. In what slit, middle or end slit, does the Philippine seafloor lies? Briefly explain your answer. Hint: You can refer to the map you used in Lesson 3

Development of Seafloor Spreading Hypothesis The seafloor spreading hypothesis was proposed by Harry Hess, a petrologist at Princeton University, and Robert Dietz, an oceanographer in the US Coast and Geodetic Survey. Hess suggested that the oceanic crust together with overlying continental crust are moving. He stated that oceanic crust spreads, starts to cool down, and become denser as it moves away from the ridge. This colder and denser oceanic crust is subducted into the oceanic trenches and will be later on melted and recycled in the mantle. Additionally, the movement of the seafloor is driven by convection in the mantle.


Harry Hess (1906–1969)

Robert Dietz (1914–1995)

Fig 26. Harry Hess and Robert Dietz, proponents of the seafloor spreading hypothesis.

In line with this, paleomagnetism is used as evidence of seafloor spreading. This is because basaltic lavas contain iron-bearing minerals which record the magnetic orientation of Earth once the lava cooled. The magnetic orientation of the oceanic crust together with the determination of the age of rocks through radiometric dating and data from Deep Sea Drilling Project help support that the ocean floor is spreading.

Fig. 27. shows the magnetic orientations of the oceanic crust along the Reykjanes ridge near Iceland which is a portion of the mid-oceanic ridge. The colored stripes represent normal polarity while the white stripes represent reversed polarity. The stripes have an alternating pattern and is arranged symmetrically on both sides of the ridge.

This discovery leads to the conclusion of geologists that there is a sequence of events that lead to the alternating bands of normal and reversed polarity of the oceanic crust. In which, new oceanic crust continuously forms as basaltic


lava rises along the ridge and as it cools, it spreads outward from the ridge. As the lava cools, it aligns with Earth’s magnetic polarity. The orientation of Earth’s magnetic field changes every half-million years in average. Therefore, the magnetic stripes actually record the magnetic orientation of Earth when the basaltic lava cooled.

Fig. 28. Magnetic reversals in the mid-oceanic ridge

This mechanism leads the scientists to the concept of seafloor spreading that explains the source of new oceanic crust. The seafloor spreading hypothesis and the plate tectonic theory greatly helped the geologist in explaining the origin and the features of the mid-oceanic ridge which is Earth’s largest mountain chain.

The mid-oceanic ridge system is one of the most spectacular features found in the deep ocean floor which covers 20% of Earth’s surface. It is a continuous submarine mountain with a length exceeding 80 000 kilometers, and some parts have a width of more than 1500 kilometers. The slightly elevated area formed by the submarine mountain was caused by the relatively lower density of the fresh hot


lava coming through the cracks. As the new lithosphere moved away from the ridge, it started to cool down creating a thicker, denser, and slightly sinking oceanic crust. The heat flow at the ridge is several times greater than the other parts of the ocean basin due to the heat flowing from the asthenosphere beneath the spreading center as well as the heat flow from the rising magma. In the given picture, the red area represents the most recent oceanic crust.

Fig. 29. Mid-oceanic ridge system

Aside from the discovery of magnetic reversals, oceanographers also studied about the thickness of the sediments along the mid-Atlantic ridge. Mid-Atlantic ridge is the segment of mid-oceanic ridge which is 1 to 2 kilometers deep and several kilometers wide. The research was conducted in this area and was found to be made up of fresh basaltic lava that is not yet covered by sediments. They observed that it is at its thinnest near the ridge axis and gradually thickens as it moves farther from the ridge. In addition, shallow earthquakes are common in the mid-oceanic ridge due to the fracturing of the crust as two lithospheric crusts moved away from each other. Transform faults are also extensive in the mid-oceanic ridge dividing it into several short segments that are slightly offset from each other. Offsets from the ridge may range from less than a kilometer to hundreds of kilometers.


Fig. 30. Transform fault in a segment of mid-oceanic ridge.

Parts of the Ocean Floor High-temperature geothermal vents called smokers are also found near or along the mid-oceanic ridge. These vents spew dark, mineral-rich fluids once in contact with the hot basaltic lava.

Fig. 31. Black smokers


Meanwhile, the greatest oceanic depths are found in oceanic trenches. These are long, steep-sided depressions on the seafloor found near convergent plate boundaries and represent 2% of the seafloor area.

Fig. 32. Challenger Deep or the Mariana Trench

Moreover, seamounts and volcanic islands are also formed in ocean basins. A seamount is a submarine mountain that has a height of 1 kilometer or more above the sea floor. If the structure rises above sea level, it is called a volcanic island. These structures are made up of basalt caused by the hot spot above the mantle plume. They form within a tectonic plate rather than at its boundary. A flat-topped seamount is called a guyot. Lastly, flat areas in the ocean floor are called abyssal plains. These areas are comprised of basaltic oceanic crust covered by deep sea sediments.


Fig. 33. The ocean floor.

● Seafloor spreading hypothesis states the seafloor moves away from the ridge crest and towards the trenches and are constantly melted and recycled in the subduction zones towards the mantle.

● Paleomagnetism and data from Deep Sea Drilling Project supported seafloor spreading hypothesis.

● Mid-oceanic ridge is the longest underwater mountain range which comprises 20% of Earth’s surface.

● Mid-Antlantic ridge is a segment of mid-oceanic ridge where most research on ocean floor is conducted.

● The different features of ocean floor include abyssal plain, seamount, guyot, trench, smoker, and volcanic island.

● Mariana trench is the deepest trench in the world.



● This video narrates the development of the theory of seafloor spreading which started Post World War II.Murray, K. 2011. ‘Sea Floor Spreading with Bill Nye.’https://www.youtube.com/watch?v=GyMLlLxbfa4

● Do want to know some interesting facts about the ocean floor? You can use this link.Lincoln Learning Solutions. 2017. ‘Ocean Floor Features’.https://www.youtube.com/watch?v=Z1b3yNgIfKw

A. Identify the term described in each questions below.1. What is the high-temperature geothermal opening on ocean seafloor

which is found along the ridge?2. Which is the deepest trench on earth?3. What oceanic land formation is like plateau in the seafloor?4. Which feature in the ocean seafloor serves as the passageway of molten

material coming from beneath the surface?5. What is the depression in the ocean floor which resulted when plates

move towards each other?6. Which is the is the longest underground chain of mountain?7. Which mineral could imprint magnetic polarity during its formation?8. What kind of striping pattern found in rocks formed which is aligned at the

ridge?9. What are the different plate movement found along the mid-oceanic

ridge?10. What kind of earthquake occurs along the mid-oceanic ridge?11. What is the study of magnetism and ancient rocks?12. What kind of lava is ejected along the ridge?


https://www.youtube.com/watch?v=GyMLlLxbfa4

https://www.youtube.com/watch?v=GyMLlLxbfa4

https://www.youtube.com/watch?v=Z1b3yNgIfKw

B. Write true if the statement is correct. Meanwhile, if the statement is incorrect then change the underlined word or phrases in order to make the statement correct.1. Seafloor spreading is the process that occurs at ridge, where new oceanic

crust is formed.2. Alfred Dietz is oceanographer who helps in mapping the ocean floor that

further supports seafloor spreading theory.3. Harry Hess is the scientist who proposed the theory of seafloor spreading.4. Silicate is the mineral which could imprint magnetic polarity during its

formation.5. Mid-Atlantic ridge is the longest geographical land formation covering 20%

of Earth’s surface.6. Scientists observed that the thickness of the oceanic crust changes

depending on its location wherein it is thickest away from the ridge.7. Paleoclimatology is one of the pieces of evidence that supported seafloor

spreading hypothesis.8. Abyssal plain is the flat area in the ocean floor.

Answer the following question using 3-4 sentence.1. How does studying the ability of rocks to record the history of Earth’s

magnetic field support Seafloor Spreading Theory?2. How will you explain the age of the rocks found in seafloor (200 million years

ago) being younger than the rocks present in the continental crust (3.96 billion years ago)?

3. Analyze the given figure and answer the following questions.

a. If you are asked to get rock samples from each section, which section contains rock sample which has the:

i. Oldest age ii. Youngest ageb. In which part can you obtain relatively middle-age rock sample?


Activity 10.1 Exploring Plate Movements

Objectives At the end of this laboratory activity, the students should be able to:

● simulate the different plate movement;● analyze the characteristics of each plate movement;

Materials and Equipment ● sand● shoe box● scissor

Procedure 1. Cut the shoe box into half. Label this as half A and half B.2. Fit together half A with half B wherein the bottom of half A overlaps with the

half B. The overlap should be approximately one inch. 3. Place a paper below the box in order to minimize dirt during the activity.4. Pour sand to the box. Make sure that the sand is evenly distributed and has a

depth of 4 inches.5. Move half A and half B of the box towards each other. Observe and draw the

resulting sand formation. Write your answer in the provided table.6. Move half A and half B of the box away from each other. Observe the

resulting sand formation.Observe and draw the resulting sand formation.Write your answer in the provided table.

7. Fill half A and half B with sand. Be sure that it has the same level of depth.8. Put together half A and half B. Instead of overlapping the open-end of half A

and half B, adjust each half in such a way that open-ends are to place side byside. Flatten the sand.

9. Simultaneously, slide half A away from you while slide half B towards you.Observe and draw the resulting sand formation. Write your answer in theprovided table.


Data and Results Table 1. Movement of the shoeboxes.

Movement Observation Illustration

Half A and half B move towards each other.

Half A and half B move apart.

Half A and half B slide opposite each other.

Guide Question 1. What is the plate boundary associated in this movement, resulting land

formation, and the stress applied in the movement? Does it involved faulting or folding? Complete the table below.

Table 2. Analysis of the processes involved in each set-up of the activity.

Movement

What plate boundary could be associated

with this movement?

What land formation is

created due to the movement in

this set-up?

Does it involve faulting or

folding?

What stress is applied on the

rock layer during the process of

plate movement?

Half A and half B move towards each other.


Half A and half B move apart.

Half A and half B slide opposite each other.

Activity 10.2 Simulating Plate Tectonics

Objectives At the end of this laboratory activity, the students should be able to:

● simulate the different plate movement; and● analyze the characteristics of each plate movement.

Materials and Equipment ● electronic gadget with internet connection

Procedure 1. Launch the PhET simulation on Plate Tectonics.

● Plate TectonicsPhET Interactive Simulations. n.d.. ‘Plate Tectonicsl.’https://phet.colorado.edu/en/simulation/plate-tectonics

2. Click the ‘Plate Motion Tab’.3. Setup a specific pair of crust. Refer to the following table.

Left Side Right Side

Continental Continental

Continental Old Ocean

Old Ocean Old Ocean

Old Ocean Young Ocean


https://phet.colorado.edu/en/simulation/plate-tectonics

https://phet.colorado.edu/en/simulation/plate-tectonics

4. In each arrow, determine the plate motion (convergent, divergent, or transform).

5. Identify the resulting land formation and number of years it takes to form such geological features.

Data and Results

Table 3. Plate movements simulation.

Left Side

Right Side

Green Arrow Blue Arrow Red Arrow

Plate motion

Land formation

No. of years

Plate motion

Land formation

No. of years

Plate motion

Land formation

No. of years

Continental Continental

Continental Old Ocean

Old Ocean Old Ocean

Old Ocean Young Ocean

Young Ocean Young Ocean

Guide Questions

1. What plate motion is simulated by the green, blue, and red arrow? Describe the relative motion in each arrow.

2. What land formation(s) resulted from the movement of the green arrow? Identify the which pair of crust created such land formation.

3. Does a given land formation readily occur immediately after the first interaction between two crusts? What does this suggest about the formation of geological features?

4. Differentiate the interaction between the continental and young oceanic crust to the interaction between between the continental and young oceanic crust in terms of angle of subduction and distance between the plate boundary and the resulting land formation.

5. What land formation(s) resulted from the movement of the red arrow? Identify the which pair of crust created such land formation.

6. What land formation(s) resulted from motion of the green arrow?


The Story of My Formation Goal

● Your goal is to make video showing the formation of the Philippines or other countries which resulted from plate movement.

Role ● You are the production staff of video production.

Audience ● Your audiences are your teacher and classmates.

Situation ● The challenge involves dealing with is collaboration with groupmates and

integrating together ideas in order to make an original video narrating the formation of Philippines or other countries which resulted from plate movement.

Product Performance and Purpose ● You need to create a video about the formation of a certain country so that

to increase the awareness of the audience about its origin which could further allow greater appreciation of the place and recognition on why such place has a specific topographical landscape, natural resources, and biodiversity.

Standard and Criteria for Success: ● Your output should include:

1. The tectonic plates as well as the interaction which led to the formation of a country should be integrated.

2. The effects of plate movements to the topographical landscape, natural resources, and biodiversity present in the given country should be discussed.

3. Some interesting facts about a given country should be included.4. The presentation of the information should clear, concise, and

accurate. 5. There should be a logical flow of the events in the story.


6. The video should be visually pleasing and the voice and other sounds, if any, should be audible.

7. Peer evaluation will be conducted at the end of the project which could affect the individual score of the student.

The following table shows the rubric in grading your output.

Criteria Below Expectations, 0% to 49%

Needs Improvement 50% to 74%

Successful Performance 75% to 99%

Exemplary Performance

100%

Content The information provides very minimal knowledge and contains misconception. It has few or does not provide reference.

The information attempts to provide correct and relevant knowledge. It also attempts to show understanding of the lesson and some list of references.

The information provided is mostly correct and relevant. It somehow reflects the understanding of the lesson and contains a list references.

The information provided are adequate, relevant, and correct. The output reflects the understanding of the lesson and contains a complete and properly cited references.

Presentation The video presentation is occasionally logical and unclear. The sound and visual file ocassionally relevant and contains distortion There are some confusing transitions which make the video minimally understandable.

The presentation is somewhat logical and clear. The sound and visual file somewhat relevant and contains some distortion. There are transitions between frames helps the audience to easily understand the concept.

The video presentation of generally logical and clear. The sound and visual file generally relevant and are free from distortion. The transitions between frames generally helps the audience to easily understand the concept.

The video presentation of has very logical and clear. The sound and visual file are relevant and are free from distortion. There is an excellent transitions between frames which helps the audience to easily understand the concept.

Technical elements and creativity

The video presentation contains minimal detail and occasionally captivating. There no titles or texts provided to enhance understanding of the content. There are a lot of technical problems in the

The video presentation is somewhat captiving and detailed. There are minimal titles or texts provided to enhance understanding of the content. There are technical

The video presentation is captiving and detailed. Generally, there are titles or texts provided to enhance understanding of the content wherein it is presented in mostly in legible

The video presentation is exceptionally captiving and detailed. Titles or texts are provided to enhance understanding of the content wherein it is presented in a legible manner.


video. problems in the video.

manner. There are minimal technical problems in the video.

There are minimal technical problems in the video.

After studying this unit, complete the following statements.

Reflect

I find __________________________ the most interesting because ______________________. I got ____ checks because _______________________________________________________. I plan to _____________________________________________________________________ .

Alfred Wegener He proposed the continental drift using several evidences such as similar fossils, coastline fit, similar rock types, and glacial evidence.

Convection It is the heat transfer which involves the rising of warm material and sinking of cold material in this case, it happens in mantle. There are two models of mantle known as layer cake model and whole mantle convection.

Continental drift hypothesis

It is proposed by Alfred Wegener. It is suggested that known landmasses were once joined in one supercontinent known as Pangaea (meaning “all- lands”) and began to break into smaller land masses about 200 million years ago.

Convergent boundary It is formed when two plates move toward each other. This is also known as destructive margins. Mountains,


island arc, and volcanic arc are formed due to the convergence of plate

Divergent boundary It is formed when two plates move apart. This is also known as constructive margins. Rift, ridge, and new seafloor are the land formations created from plate divergence.

Fault It is a fracture or a discernible displacement where rocks grind or slide past each other. This different types of faults include normal dip-slip fault, reverse dip-slip fault, strike slip fault, and oblique fault

Fold It is series of wavelike ripples or bends which is mostly formed when rock layer is subjected to compressive stress. It is composed of upward fold known as anticline while downward fold as syncline.

Harry Hess He proposed the seafloor spreading hypothesis together with Robert Dietz

Joint It is also fracture in a rock but unlike faults, joints do not produce discernable displacements.

Mid-oceanic ridge It is the longest underwater mountain range which comprises 20% of Earth’s surface.

Plate tectonics theory This theory is combines the idea of the continental drift and seafloor spreading, stating that Earth is divided into several lithospheric plates that move relative to each other. It is supported by data obtained from ocean drilling project, paleomagnetism, and apparent polar wandering.

Seafloor spreading hypothesis

It suggested that seafloor is moving away from the ridge which is driven by mantle convection.

Slab pull It is the force which causes the oceanic plates to move downward at subduction zones.

Stress It is a force exerted on an object, in this case, a rock. The different types of stress include confining stress and directed stress, which is further subdivided into tensional, compressional, and shear stress.

Ridge push It is the force that causes warm and less dense material to force itself up through a ridge.


Rock deformation This involves changes shape and/or size which can either be permanent or temporary. The different types rock deformation include elastic, brittle, and ductile deformation.

Transform plate boundary

Two plates simply slide horizontally past each other. Fault zones are formed in transform plate boundary.

Plate Tectonics Theory


Fig. 1. Alfred Wegener. by Unknown is licensed under Public Domain via Wikimedia

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Public Domain via Wikimedia Commons. Fig. 7. Lithospheric Plates by USGS is licensed under Public Domain via Wikimedia

Commons. Fig 26.1. Harry Hess by Unknown is licensed under Public Domain via Wikimedia

Commons. Fig 26.2. Robert Dietz by Unknown is licensed under Public Domain via Wikimedia

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Wikimedia Commons. Fig. 31 Black smokers by P. Rona. is licensed under Public Domain via Wikimedia

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Documents

Unit 1 Plate Tectonics