2. How Do We Get
The Earth’s Magnificent
Features?
3. How The Earth Formed
• The Earth formed from the same dust cloud that formed the sun.
• As the dust circled around the sun it clumped and began to grow.
4. How The Earth Formed
• Soon a proto-planet formed that swept up the remaining dust
and particles in its path.
5. The Early Earth
• The beginning of Earth was marked with volcanic action and
bombardment from meteors.
• Meteors added essential elements crucial for life.
6. The Early Earth
• After a while the Earth cooled, an atmosphere formed and the
crust solidified.
• Volcanic (outgassing) activity contributed to the atmosphere.
• Comets and Meteors
contributed the the water
on Earth.
7. What is the Earth Made Of ?
Composition of Earth's Atmosphere Composition of Earth
Nitrogen 78.1% Iron 32.1%
Oxygen 20.9% Oxygen 30.1%
Argon 0.9% Silicon 15.1%
Carbon dioxide, Methane, Magnesium 13.9%
Rare (inert) gases 0.1% Sulfur 2.9%
Nickel 1.8%
Calcium 1.5%
Aluminum 1.4%
Other 1.2%
8. Earth’s Rocks
• Igneous Rocks--formed when molten magma cools and are divided
into two main categories: plutonic (intrusive) and volcanic (extrusive).
Intrusive rocks result when magma cools and crystallizes slowly within
the Earth's crust (example granite), while volcanic or extrusive rocks
result from magma reaching the surface either as lava or fragmental
ejecta (examples pumice and basalt)
Pumice
Granite
9. Earth’s Rocks
• Sedimentary Rock--For thousands, even millions of years, little
pieces of our earth have been eroded--broken down and worn away by
wind and water. These little bits of our earth are washed downstream
where they settle to the bottom of the rivers, lakes, and oceans. Layer after
layer of eroded earth is deposited on top of each. These layers are pressed
down more and more through time, until the bottom layers slowly
turn into rock.
10. Earth’s Rocks
• Metamorphic Rock--formed by subjecting any rock type to
different temperature and pressure conditions than those in which the
original rock was formed. These temperatures and pressures are always
higher than those at the Earth's surface and must be sufficiently high so as
to change the original minerals into other mineral types or else into other
forms of the same minerals.
12. The Layers of the Earth
• The inner core is solid iron
• The outer core is liquid iron
• The mantle is composed of iron (Fe), magnesium (Mg),
aluminum (Al), silicon (Si), and oxygen (O) silicate
compounds.
• The mantle is solid but is at a
temperature of 1000o C, so it
can deform slowly like hot plastic.
• The crust is composed of calcium
and sodium aluminum-
silicate minerals.
• The crust is thin, cool and brittle.
It can break and crack easily.
13. Convection
• Something that is hot is less dense than something that is cool.
• More dense (cooler) things will tend to sink while less dense
(hotter) things will tend to rise.
14. Convection in the Earth
• The convection process happens in the Earth as well.
• The cooler, denser crust will sink to the bottom, while the
hotter, less dense inner regions will rise to the top.
• When convection
happens on the Earth
it drives a process
known as
Plate Tectonics.
15. Plate Tectonics
• The Earth’s crust is broken into different segments.
• These different segments are called plates.
• There are seven major plates.
• These plates move (slowly) over the earth, crashing and
grinding against each other.
17. Continental Drift
• In the past all the continents were one large continent
named Pangaea.
• Plate tectonics contributed to the breakup of Pangaea into the
continents we have today.
• The continents continue to move about 5 to 10 cm per year.
18.
19. Effects of Plate Tectonics
• Earthquakes happen when two plates rub against each other.
• Ridges form when two plates move apart from one another.
• Volcanoes and trenches other mountains form when two
plates
collide.
20. Earthquakes
• The boundary where two plates rub against each other is called
a transform boundary.
• Earthquakes occur along
this boundary also
called a fault.
22. Ocean Ridges
• Ocean ridges form when two plates pull apart from on another.
• This is known as a divergent boundary.
• Hot magma will rise up at this boundary, solidify, and form
underwater mountain ranges.
24. Volcanoes
• A convergent boundary
is where two plates
collide.
• When plated collide,
one plate usually gets
subducted, or pushed
beneath the other plate.
This is known as a subduction zone.
• Volcanoes and earthquakes form near these subduction zones.
25. Volcanoes
As the subducted plate
sinks, it will grow hot,
melt, and form magma
which will rise under
pressure and form an
earthquake.
When the pressure
grows strong enough it
will erupt
29. Effects of Volcanoes on Earth
Volcanic soil is ideal for plant growth.
Volcanoes added much needed water vapor to Earth’s
atmosphere in the beginning.
Large eruptions can cause a mass extinction of plant and
animal species. This happens mainly from the ash that
lingers in the atmosphere for long periods of time,
blocking the sun. Some of the poisonous gas will rain
down in the form of acid rain.
30. Hot Spot Volcanoes
Hot Spot volcanoes
are less violent than
those near subduction
zones.
The crust slowly
moves over a “hot
spot”—an area of
magma formation.
The movement will
create a string of
volcanic islands that The Hawaiian islands were formed
will cool and flourish
with life. (and are still being formed) by a
hot spot volcano.
32. Mountains
Mountains can
form when two
plates collide
causing one or
both plates to
rise up.
Other Mountains
are formed when
a plate under
pressure will
swell, fold and
fault.
35. Mt. Everest
Mt. Everest is the highest mountain in the world. It is
29,028 ft. (5 ½ miles) high. Mt. Everest is part of the
Himalayan mountain range which was formd when the
the Indo-Australian plate collided with the Eurasian
plate.
37. Mountains
Other mountains
are formed by the
erosion of high
plateau regions,
leaving the
harder parts
standing above
the surrounding
area.
38. Glaciers
A glacier forms when the annual snowfall exceeds
the amount of snow and ice lost due to melting.
Snow thus accumulates year after year. The snow
at the bottom is compacted into ice (firn).
Eventually the weight of the snow and ice
becomes so large that the glacier begins to slowly
fall (drift) downhill.
The glacier carves a path in the landscape and
leaves debris in behind.
39. Glaciers
• Glaciers carve
mountains and
valleys
• Much of the shapes
we see in
mountain ranges
is a result of
glaciers.
45. Glaciers—Hanging Valleys
Hanging Valley—the intersection of two
valleys which were carved by glaciers. One
of the valleys is larger and deeper than the
other. The smaller valley “falls into” or
“hangs” over top of the larger valley.
Waterfalls often occur at these
intersections.
49. Agents of Erosion
Erosion is the breaking down of a material.
Wind, Water and Chemicals are the main
agents of erosion.
These also help carve out our Earth.
50. Wind Erosion
Wind will blow small debris (sand
and other particles) that will carve
out features in rocks, mountains
and anything else in its path.
51. Water Erosion
Rain and rivers, over time, carve away at
rocks.
Rivers will cut into the landscape and can
form valleys and canyons over time.
Oceans constantly shape the shores and eat
into cliffs.
55. Chemical Erosion
Chemicals put into the atmosphere will
come down in the form of acid rain and
alter and destroy some landforms.
Other chemicals will seep into the ground
and waters change the composition of their
contents.
56. Other Types of Erosion
Water freezing in cracks and expanding
Roots of plants growing into crevasses and
growing to the point that the crack or
crevasse widens and breaks.
Human activity. Building, cutting down,
blowing up, etc.
