q1_-module-6.pptxprsentationonsdience10quarter1

Science 10 presentation

1. Quarter 1 — Module 6:
Possible Causes of
Plate Movement

2. Content Standard:

The learners demonstrate an understanding
of the relationship among the locations of
volcanoes, earthquake epicenters, and
mountain ranges.

3. ' „Guide questions
L / 1. What are the two types of plates?
ME HA 2. How do plates move?

What geologic features are formed?
. What causes the movement of the pla

4. Possible Causes of Plate Movement

1.Convection Current
2.Ridge Push

3.Slab Pull mu

5. Causes of Plate Movement

MakeAGIF.com

6. Possible Causes of Plate Movement

There are three forces working to move the plates.
1. Convection Current
2. Ridge Push
3. Slab Pull

ridge push

7. Possible Causes of Plate Movement

Convection Current

> Heated mantle material is shown rising from deep inside
the mantle, while cooler mantle material sinks, creating a
convection current.

>It is thought that this type of current is responsible for the
movements of the plates of Earth's crust.

ridge push

8. Possible Causes of Plate Movement

>This process can also take place in the Earth’s mantle. The
temperature difference in the mantle causes the
movement of the molten materials.

>The hot, less dense materials rise and the cooler, denser
materials sink.

> This process of rising and sinking molten materials is
called MANTLE CONVECTION.

9. Mechanisms for Plate Motion

>forces cause two plates to pull apart on the surface.

>The lithosphere rocks SLIDE away from the ridge, due to
gravity, down the sloping asthenosphere.

> The asthenosphere is less dense than the rocks above it
making it possible for the cooled lithosphere rocks above it
to slide down the slope of the asthenosphere.

ridge push

10. Mechanisms for Plate Motion

>The process continues in the ridge where new molten
magma wells up and becomes the new lithosphere.

>This force that the rocks exert at the ridge to spread the
lithosphere is called RIDGE PUSH.

It refers to the pushing force that plates experience as

they slide down the raised asthenosphere underneath Mid

Ocean Ridges.

ridge push

11. Mechanisms for Plate Motion

» forces pull the plates down.
>The force that the sinking plate exerts on the rest of the
plate is called SLAB PULL.

> The edge of the subducting plate is much colder and
heavier than the mantle, so, it continues to sink pulling the
rest of the plate connected to it.

ridge push

12. Mechanisms for Plate Motion

> As the plate moves away from the diverging boundary, it
ages and cools, thus becoming much denser.

> The cold, dense lithosphere then sinks down into the
asthenosphere (at subduction zones) and "pulls" the rest of
the plate along with it.

ridge push

13. Mechanisms for Plate Motion

Slab-Pull and Push Ridge

> Occur only in Mid-oceanic Ridges.

Divergent Boundary—Fast-spreading Ridge
(otto scale)

1) Hot mantle rock rises.
2) Melt forms under the lithosph
3) Magma rises into magma chamber

in crust and is injected as dikes
forming new crust
4) Lava erupts onto ocean floor addi
5) Plates move apart, cool, and thick

14. Theories of Plate Tectonic Movements

Seafloor Spreading Theory

> proposed by Harry Hess (1960)

> is a geologic process in which tectonic
plates —large slabs of Earth's
lithosphere—split apart from each
other.

> is the mechanism by which new
oceanic lithosphere is created at and
moves away from divergent plate

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15. Theories of Plate Tectonic Movements

Seafloor Spreading Theory
> 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.
L / > Seafloor spreading occurs at
META divergent plate boundaries.

16. GUIDE CARD Theories of Plate Tectonic Movements

Seafloor Spreading Theory

> 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.

> Eventually, the crust cracks. Hot
magma fueled by mantle convection
[bubbles up to fill these fractures and

li onto the crust.

> This bubbled-up magma is cooled by

frigid seawater to form igneous rock.

This rock (basalt) becomes a new part

of Earth’s crust.

17. GUIDE CARD © Theories of Plate Tectonic Movements à of Plate Tectonic Movements

Seafloor Spreading Theory

> Mid-Ocean Ridges Seafloor spreading

occurs along mid-ocean ridges—large

mountain ranges rising from the

ocean floor.

The Mid-Atlantic Ridge

> separates the North American plate
from the Eurasian plate, and the
South American plate from the

W | frican plate.
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18. GUIDE CARD © Theories of Plate Tectonic Movements of Plate Tectonic Movements

|

Seafloor Spreading Theory
> The East Pacific Rise is a mid-ocean

ridge that runs through the eastern
Pacific Ocean and separates the
Pacific plate from the North
American plate, the Cocos plate, the
Nazca plate, and the Antarctic plate.
> The Southeast Indian Ridge marks
where the southern Indo-Australian
plate forms a divergent boundary
Lu” the Antarctic plate.
lei

19. GUIDE CARD Theories of Plate Tectonic Movements of Plate Tectonic Movements

Seafloor Spreading Theory
+ The Mid-Atlantic Ridge, for instance,

is a slow-spreading center. It
spreads 2-5 centimeters (.8-2
inches) every year and forms
an ocean trench about the size of
the Grand Canyon.

> The East Pacific Rise, on the other
hand, is a fast-spreading center. It
spreads about 6-16 centimeters (3-6

ur every year.
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