andes mountains, south america
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Andes Mountains, South America
Evidence of Continental Drift
Earth’s Layers
Layers of the Earth
• There are two ways that scientists label the layers of the Earth.– Composition layers– Physical layers
Composition (What it is made of)
• Crust
• Mantle
• Core
Earth’s Layers
• How are the earth’s layers similar to an egg?
• Shell=crust• Egg white=mantle• Yolk=core
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)
Oceanic and Continental 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
Convection Currents
Convection Currents Cause the Tectonic Plates to move
Movement of these plates Cause:
1.Earth Quakes2.Mountains3.Volcanoes4.Rift valleys5.Tsunamis
Tectonic Plates• Earth’s crust is broken into about 19
pieces
• These plates move on top of the asthenosphere
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
• The less familiar layers are the physical layers.
• They are based on how the layer looks or acts.
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 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
• Layer found between the asthenosphere and the outer core
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
Side by side comparison
LithosphereLithosphere
AsthenosphereAsthenosphere
Outer CoreOuter Core
Inner CoreInner Core
CrustCrust
MantleMantle
CoreCore
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
– 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…
• 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