Name: ARIANETTE C.

ATILAS
Grade/Section: G11-STEM-A EARTH SCIENCE Q2-MODULE 7
Structure and Evolution of Ocean Basin
What I Know
1.B 6.C 11.A
2.C 7.D 12.B
3.D 8.B 13.C
4.C 9.A 14.B
5.C 10.B 15.A
What’s In
Direction: Observe and analyze the given illustration. Answer the questions that follow.

1. Based from the illustration, what do you think causes the sea floor to spread?
 Based from the given illustration, I think the factor that causes the sea-floor to spread is what happens at the
mid-oceanic ridge where a divergent boundary is causing two plates to move away from one another resulting
in spreading of the sea floor. As tectonic plates slowly move away from each other, heat from the mantle's
convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a
mountain or elevated area of the seafloor.
2. What does the picture tell us about our ocean and continents?
 The picture tells us that the continents are moving (drifting) through unmoving oceans. Seafloor spreading
proves that the ocean itself is a site of tectonic activity. The Earth’s surface may seem motionless most of the
time, but it’s actually always moving, ever so slowly, at a scale that is difficult for humans to perceive. The
Earth’s crust is broken up into a series of massive sections called plates. These tectonic plates rest upon the
convection mantle, which causes them to move. The movements of these plates can account for noticeable
geologic events such as earthquakes, volcanic eruptions, and more subtle yet sublime events, like the building
of mountains.
3. What other things have you learned about sea floor spreading?
 Other than that, in the previous lessons about Sea floor spreading I learned that Seafloor spreading and other
tectonic activity processes are the result of mantle convection. Mantle convection is the slow, churning motion
of Earth’s mantle. Convection currents carry heat from the lower mantle and core to the lithosphere.
Convection currents also “recycle” lithospheric materials back to the mantle.
What’s New
Direction: Read the statement and answer the following question.
Philippine Trench, also called Philippine Deep, Mindanao Trench, or Mindanao Deep, is a submarine trench in the
floor of the Philippine Sea of the Western North Pacific Ocean bordering the east coast of the island of Mindanao. The
abyss, which reaches the second greatest depth known in any ocean, was first plumbed in 1927 by the German ship
Emden and found to have a depth of 34,440 feet (10,497 meters). How was this trench formed?

 The Philippine Trench was formed from a collision between the Palawan and
Zamboanga plates. This caused a change in geological processes going from a
convergent zone to a subduction zone. The subduction zone is located west to east
of the Philippine Islands. Trenches are formed by subduction, a geophysical process
in which two or more of Earth's tectonic plates converge and the older, denser plate
is pushed beneath the lighter plate and deep into the mantle, causing the seafloor
and outermost crust (the lithosphere) to bend and form a steep, V-shaped
depression.
What’s More
A. Direction: Loop the word or phrase that pertains to the structure of the ocean basin. List down and describe
each on the table provided.
Structure of the Ocean Basin Description
1. Continental Shelf Partly shallow extension of the continent underwater.
2. Continental Slope It starts from oceanic crust to continental crust.
3. Continental Rise It is the place where the sediments from the land are washed
4. Abyssal Plain The flattest part of the ocean. 50% of the earth’s surface is being covered
by this plain
5. Island It’s not just a piece of land floating up in the middle of the sea; it is part of
the ocean basin that extends up from the ocean floor.
6. Seamount It is an undersea mountain. The erosion caused by waves destroyed the
top of a seamount which caused it to be flattened.
7. Trench It is the deepest part of the ocean.
8. Mid-Oceanic Ridges The seafloor mountain system which is situated in the middle of the ocean
basin. It is where upwelling of magma happens which causes the sea floor
to spread.

What’s More
B. Direction: Loop the word or phrase that pertains to the structure of the ocean basin. List down and describe
each on the table provided.
Stages Motion Description Example
1. Embryonic Uplift Complex system of linear rift valleys on East African Rift Valleys
continent
2. Juvenile Divergence Narrow seas with matching coasts Red Sea
3. Mature Spreading Ocean basin with continental Margins Atlantic and Arctic
Oceans
4. Declining Subduction Island Arcs and Trenches around basin Pacific Ocean
edge
5. Terminal Collision and Uplift Narrow irregular seas with young Mediterranean Seas
mountains
6. Suturing Convergence and Young to mature Mountain belts Himalayas Mountains
Uplift
ARIANETTE C. ATILAS G11-STEM-A ES-Q2-M7
What I Have Learned
Directions: Using the concepts learned in this module, make a concept map.

PANGEA
During the Triassic period, the immense
STRUCTURE AND EVOLUTION Pangea landmass began breaking apart
OF OCEAN BASIN as a result of continental rifting. A rift
running width of the supercontinent
 Continental shelf began to open up an ocean that would
 Continental slope eventually separate the land mass into
two enormous continents.
 Continental rise
 Abyssal plain
 Island
FOUR MAJOR OCEAN
 Seamount
SUBDIVISION
 Trench
 Mid-ocean  North and south pacific
 North and south Atlantic
 Indian ocean
 Arctic ocean

WILSON CYCLE
 The Wilson cycle explains the
EVOLUTION OF THE OCEANIC process of the opening
(beginning) and the closing (end)
BASIN (STAGES OF WILSON
of an ocean which is driven by
CYCLE) plate tectonic.
 Embryonic ocean Basin
 Juvenile ocean basin
JOHN TUZON WILSON
 Mature ocean basin
 Declining ocean basin  Canadian geologist and
geophysicist who established global
 Terminal ocean basin patterns of faulting and the structure
 Suturing ocean basin of the continents. His studies in
plate tectonics had an important
bearing on the theories of
continental drift, seafloor spreading,
and convection currents within the
earth.
ARIANETTE C. ATILAS G11-STEM-A ES-Q2-M7
What I Can Do
In your own words, briefly explain the formation of the following geologic structures:

Geologic Structure How are they formed Illustration

1. Volcano The majority of volcanoes in the world
form along the boundaries of Earth's
tectonic plate. When tectonic plates
collide, one often plunges deep below
the other in what's known as a
subduction zone. Another way
volcanoes can form is what's known as
hotspot volcanism. In this situation, a
zone of magmatic activity or a hotspot,
in the middle of a tectonic plate can
push up through the crust to form a
volcano.

2. Mountain Ranges Mountains form where two continental

plates collide. Since both plates have a
similar thickness and weight, neither
one will sink under the other. Instead,
they crumple and fold until the rocks
are forced up to form a mountain
range. As the plates continue to collide,
mountains will get taller and taller.

3. Ocean Basin An ocean basin is formed when water

has covered a large portion of the
Earth's crust. Over a long period of
time, an oceanic basin can be created
by the spreading of the seafloor and
the
movement of tectonic plates. The upper
crust is deformed by ductile stretching
while the lower crust is broken along
normal faults. Tension pulls apart the
crusts and crust slab sink in the
middle, forming a rift valley, continued
spreading creates a narrow sea after
continued spreading, an ocean and
ridge system are created.
ARIANETTE C. ATILAS G11-STEM-A ES-Q2-M7
Additional Activities
Directions. Using the world map, identify and locate at least 5 places where the six
stages of the Wilson Cycle occur.
Stages Example Location
1. Embryonic East African Rift Valley is
one of the most extensive
rifts on Earth’s surface,
extending from Jordan in
southwestern Asia
southward through eastern
Africa to Mozambique.

2. Juvenile Red Sea is in the Middle

East, between Egypt and
Saudi Arabia.

3. Mature Atlantic Ocean is known to

separate the "Old World" from
the "New World" in the
European perception of the
World.

4. Declining Subduction eliminates

much of sea floor and
Oceanic ridge in Pacific
Ocean.

5.Terminal Mediterranean is an
intercontinental sea located
between Europe, North Africa,
and Western Asia and
connected to the Atlantic
Ocean through the strait of
Gibraltar.
6. Suturing The Himalayas stretch
across the northeastern
portion of India. They
pass through the nations
of India, Pakistan,
Afghanistan, China,
Bhutan and Nepal.