section 4.1 vocabulary to knowcrust mantle core lithosphere continental crust oceanic crust...
TRANSCRIPT
Section 4.1
• Vocabulary to know• Crust• Mantle• Core• Lithosphere• Continental crust• Oceanic crust• Asthenosphere• Mesosphere• Outer core• Inner core• Radioactivity
Earth’s interior…• Made up of:
– Crust, mantle, and core
Crust
• Crust-– Outermost and
thinnest layer of Earth.
– Relatively cool.• Two types:
– Oceanic crust• Crust beneath
ocean (2.5-4.3 mi thick)
• More dense– Continental crust
• Crust beneath continents (12-25 mi thick)
• Less dense
In between the crust and mantle… sort of…
• Lithosphere-– The thin outer shell
of the Earth.• Consists of the
crust and the rigid upper mantle.
• Asthenosphere-– Beneath
lithosphere (in the mantle).• Consists of slowly
flowing solid rock.
This Sucks!
Mantle
• Mantle-– Layer of rock between
Earth’s crust and core.
– More dense than the crust (which is why it’s beneath it).
– Makes up about 80% of Earth’s volume.
– Outer mantle-• Rocks mostly solid.
– Inner mantle-• Rocks easily deformed
Core
• Core-– Center of a
planetary body.– Composed of
iron (Fe) and Nickel (Ni).
• Two layers:– Outer core
• Liquid metal
– Inner core• Solid metal
Where is it the hottest?• The Earth gets hotter
as you go deeper!– Crust ( ~347o F)– Mantle (~2280o F)– Outer core (~7000o F)
• So hot that the rocks actually melt!
– Inner core (~10,800o F)• So hot that the rocks
melt BUT so much pressure that they remain a solid!
Why is the Interior so hot?• It contains
radioactive isotopes.– Uranium, Thorium,
and Potassium• Their nuclei break
up (decay) releasing energy as they become smaller nuclei.
• Earth is huge…so there is a lot of energy being released.
How to remember the 5 physical Structures of the Earth…in order
• Using the hand method
1st Layer
LITHOSPHERE
2nd LayerASTHENOSPHERE
3rd LayerWhat would three scared foreigners say if they don’t speak english and are trapped under two of Earth’s physical structures?
MESOSPHERE (ME SO FEAR)
4TH Layer
What was Lincoln know for saying?
Four SCORE and 7 years ago. (Outer)
5th Layer
These guys are???
INNER
Section 4.2 and 4.3
• Vocabulary to know• Plate tectonics• Continental drift• Alfred Weggener• Pangaea• Convection currents• Subduction• Sea-floor spreading• Mid ocean ridge• Rift valleys• Trench• Magnetic striping
PLATE TECTONICS
• Plate Tectonics- – theory that explains the
formation and movement of earth’s plates
• Continental Drift- – Alfred Weggener’s theory
that continents were once joined in a single supercontinent, which then broke into pieces that moved apart.
– Move 0.4 to 6.3 in. per year
Continental Drift
• How could a fresh-water animal (Mesosaurus) be found on two continents that are separated by an ocean?
• Could it be…
Evidence of Continental Drift
• …Continental drift!– Many fossils
matched up perfectly once the continents were put together.
– The continents also fit together like puzzle pieces.
– But how could continents move?
Scientists aren’t quite sure…
• …but they think it might be due to convection currents.
Water rises because it’s less dense… then cools and sinks as it becomes more dense.
Sea-floor Spreading
• Would you expect the middle of the ocean to be its deepest point?– Why or why not?
Ridges
At its peak, the mid-ocean ridge has a valley, also known as a rift…
What happens when plates run into plates?
• Mariana Trench – Lowest point on
Earth.• 35,798 ft below sea
level.
Mount Everest from space.Highest point on
Earth29,028 ft above
sea level.
Subduction
Subduction• Trench-
– as a plate sinks through a subduction zone, it bends forming a depression in the ocean floor.
• What is the deepest point in the ocean?
Subduction• Sea-floor spreading- creates new oceanic crust
at mid-ocean ridges.• Subduction- destroys old oceanic crust at
subduction zones.
Evidence
Evidence• Magnetic striping
– Tiny grains of magnetite in the rock of the ocean floor behave like little magnets.
– Align with orientation of the Earth’s magnetic field.
– Points north presently…• Not always the
case…