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Andes Mountains, South America. Evidence of Continental Drift. Fossils Similar fossils of several different animals and plants that once lived on land had been found on widely separated continents. The ages of different fossils predated Wegener’s time frame for the breakup of Pangaea.

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Andes mountains south america
Andes Mountains, South America


Evidence of continental drift
Evidence of Continental Drift

Fossils

  • Similar fossils of several different animals and plants that once lived on land had been found on widely separated continents.

  • The ages of different fossils predated Wegener’s time frame for the breakup of Pangaea.


Fossils

  • Fossils of Glossopteris, a seed fern that resembled low shrubs, have been found on many continents, indicating that the areas had a single climate that was close to the equator.



Layers of the earth
Layers of the Earth

  • There are two ways that scientists label the layers of the Earth.

    • Composition layers

    • Physical layers



Earth s layers1

How are the earth’s layers similar to an egg?

Shell=crust

Egg white=mantle

Yolk=core

Earth’s Layers


The crust

Outer layer

5-100 km thick

Thinnest layer

2 types of crust

Oceanic (very dense, made of basalt)

Continental (less dense, made of granite)

The Crust



The mantle

Middle layer

Very thick layer

Roughly 2800 km thick

No one has ever drilled to the mantle

It is VERY hot

composed of silicate rocks that are rich in iron and magnesium

Even though its solid it can flow

The Mantle


Convection currents
Convection Currents

Convection Currents Cause the Tectonic Plates to move

Movement of these plates Cause:

Earth Quakes

Mountains

Volcanoes

Rift valleys

Tsunamis


Tectonic plates
Tectonic Plates

  • Earth’s crust is broken into about 19 pieces

  • These plates move on top of the asthenosphere


The core
The Core

  • Made mostly of Iron and Nickel

  • 1/3 of the earth’s mass

    • Very hot

    • The core’s diameter is about the size of Mars (6856 km )


Physical layers
Physical Layers

  • The less familiar layers are the physical layers.

  • They are based on how the layer looks or acts.


Physical structure of the earth
Physical Structure of the Earth

  • Lithosphere (Crust) - (15-300 km) rigid outer layer

    • The tectonic Plates

    • A combination of crust and the upper region of the mantle

    • Cold and brittle (easily broken)


Physical layers1
Physical Layers

  • Asthenosphere

  • weak sphere” (250 km)

    • Hard rock that acts like warm tar or honey

    • Ductile and highly Viscous

  • involved in plate tectonic movements


  • Mesosphere
    Mesosphere

    • Layer found between the asthenosphere and the outer core


    Physical layers continued
    Physical Layers Continued

    • Outer Core- (2200 km)

      • liquid layer

    • Inner Core-(diameter= 2456 km)

      • Solid, dense core of the planet

      • Densest layer of the planet



    The spheres
    The “spheres”

    • Atmosphere

      • Least dense layer of the Earth

      • Made of mostly oxygen and nitrogen

      • Surrounds the Earth

      • Filters out harmful radiation


    • Biosphere

      • Layer that all life is in

      • Not a specific location, just anywhere life is found


    Hydrosphere
    Hydrosphere

    • Density= ~1.0 g/mL

  • Describes the combined mass of water found on, under, and over the surface of a planet.

  • Approximately 75% of the Earth's surface, an area of some 361 million square kilometres (is covered by ocean.


  • Interesting fact
    Interesting fact…

    • Did you know?...

      • The center of the Earth’s core is hotter than the surface of the sun. The temperature of Earth’s inner core reaches 6000 °C whereas the surface of the sun is roughly 5500 °C.

        • The sun’s core, however, is 15,000,000 °C


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