Grade 10 First Grading

1. Tectonic
Plates(Part 1)
 Continental Drift
Theory
 Seafloor Spreading
 Volcano
 Earthquake

2. What is inside the Earth?
1. Earth is made of several layers.
2. Each layer has its own characteristic
properties.
3. Scientists think about Earth’s layers in two
ways—in terms of chemical composition and
in terms of mechanical.

3. Mesosphere
Asthenosphere
Earth
Mechanical
Crust
Composition
Mantle
Core
Lithosphere
Inner & Outer Core

4. Earth can be divided into three primary layers based on chemical
composition:
 the crust - is the outermost layer of a planet. It composed of
two layers the oceanic and continental crust.
 the mantle - the mantle is located between the crust and the
core. The mantle is a region of hot, slow-flowing solid rock.
 the core - Earth's inner core is the innermost geologic layer
of the Earth. It is the very hot, very dense center of our planet.
It is lies beneath the cool, brittle crust, and the mostly solid
mantle.
What are Earth’s compositional layers?

5.  The continental crust is made mostly
of rocks with a composition similar to
granite (a light-colored rock you
would expect to find in the Sierra
Nevada). Crust that is made of land.
 The oceanic crust is made mostly of
rocks with a composition of basalt
(dark-colored rock, like the rocks that
make up the Hawaiian volcano).
 Crust below the ocean.
Continental & oceanic Crust

6.  Lithosphere is the
outermost, rigid layer of
Earth
a. The lithosphere is made of
the crust and the rigid,
upper part of the mantle.
b. The lithosphere is divided
into pieces called tectonic
plates.
What are Earth’s physical layers?
 Asthenosphere is the layer
of weak or soft mantle made
of solid rock that moves very
slowly.
a. The asthenosphere is located
below the lithosphere.
b. Tectonic plates move on top of the
asthenosphere.

7.  Mesosphere the strong,
lower part of the mantle.
a. Rock in the mesosphere flows
more slowly than rock
in the asthenosphere.
 Outer core is the liquid layer of
Earth’s core.
a. The outer core lies beneath the
mantle and surrounds the inner core.
 Inner core is the solid, dense
center of our planet.
a. The inner core extends from the bottom
of the outer core to the center of Earth.

8. History of Plate Tectonic
 Pangea
 Continental Drift Theory
 Seafloor Spreading
 Tectonic Plate

9.  It was Propesed by
Alfred Wegener in
1912
 250 million years ago,
all the continents were
combined into one
super continent called
“Pangaea”.
 The continents
gradually drifted apart
to where they are
today.
Continental Drift Theory

10. Pangea
 “Pan” means entire or
whole; “Gaia” means
Mother Earth or land.
 was a supercontinental that
existed during the Palezoic
and early Mesozoic. Pangea
was centred of Equator and
surrounded by the
superocean Panthalasa

11. Evidence
• Puzzle: Continents can fit
together like a puzzle.
• Fossils: Similar fossils
were found on coastlines
of different continents.
• Rock Types: Mountains
that appear on another
continent across the ocean.

12. Types of Seafloor
Spreading
 Seafloor Spreading is the
usual process at work at
divergent plate boundaries,
leading to the creation of new
ocean floor.
 As two tectonic plates slowly
separate, molten material
rises up from within the
mantle to fill the opening.
 The rugged volcanic
landscape of a mid-ocean
ridge is created along the
plate boundary.
Seafloor Spreading
 Convergent – where plates
collide
 Divergent – where plates
separate
 Transform – where plates
simply slide past each other.

13. • A mountain under the ocean
• A mid-ocean ridges forms where oceanic
plates continue to separate.
Mid-Ocean Ridges
Oceanic-oceanic

14. • When continental plates pull apart, they form rift
valleys.
• Makes volcanoes and new land
• Example: East African Rift Valley
Rift – Valleys
Continental-continental

15. Convection Currents
• Convection cells in the mantle move the plates.
- Hot in the center, less dense magma rises up due to heat.
- When the magma reaches the surface, it cools and sinks back down creating
circular pattern of movement.
• This process happens continually.
• Hot – goes UP
• Cool – goes DOWN

16. Plate Tectonic
 Plate tectonics is the theory that Earth's outer
shell is divided into several plates that glide over
the mantle, the rocky inner layer above the core.
 The theory of plate
tectonics, the crust is
broken up into
section/pieces that move
on top of the liquid
mantle (asthenosphere).
 To main types of plate
oceanic and continental.

17. Plates
Major Tectonic Plates
• Eurasian
• African
• Australian-Indian
• North America
• Pacific
• Antarctic
• South America
Minor Tectonic Plates
● Carribean
● Cocos
● Nazca
● Arabian
● Philippine
● Juan de Fuca
● Scotia
There are 7 major plates on the earth that are moving extremely slowly but
continuously.

18.  https://www.livescience.com/37529-continental-
drift.html#:~:text=Continental%20drift%20was%20a%20theory,are%20foun
d%20on%20different%20continents.
References

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