Transcript Unit 2 Review and Solutions

Unit 2 Review and Solutions
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Lithosphere (Rock)
Hydrosphere (Water)
Atmosphere (Air)
Biosphere (Living things)
– Volcano - L - Creates new rock, large amounts of
ash produced, plate movements
– A - larges amounts of ash enter the air polluting it,
darkens the sky blocking the sun, sulfur dioxide
– H - Gases like sulfur Dioxide mix with water
vapour to create Sulfuric Acid (Acid Rain)
– Bio - Ash can wipe out trees with pyroclastic flows,
obviously kill people
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• Precambrain (Eon)
– Hadean (Era)
– Archeaen (Era)
– Proterozoic (Era)
Largest aspect of the geologic Timeline
Paleozioc
Mesozoic (Triassic, Jurassic, Cretaceous)
Cenozoic
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• Geologic events take 1000’s of years to
form
• Human life span is 80 years
• We cannot see formation and process
happening
• Human existance has really only been
around for a fraction of time in the
earths history (I step on a football field)
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• Sedimentary - Rock that mainly forms in
layers
– Clastic (Cementation)
– Biogenic (Formed form Living Organism and Sea
Creatures when they die)
– Chemical (Rock formed from natural chemical
processes and cementation)
• Igneous
– Extrusive (Lava hardened on surface)
– Intrusive (Magma hardened below the surface)
• Metamorphic
– Add heat and pressure to change the state of a
rock from one form to another
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• Relative Dating (Not an exact date)
– Superposition - Each layer of rock is older than the
one above it
– Uniformitarianism - To understand how a geologic
structure is formed we assume that present day
processes operated in the same way thousands of
years ago. (ex. Erosion) We can determine the
relative age of a geological structure by observing
how quickly or slow it is changing today
– Fossil Correlation - A period of time can be define
by it’s fossil content in a layers of rock
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• Earthquakes happen because of the
interactions at plate boundaries
– Plates get stuck and move to create an
earthquake
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• BODY WAVES - Travel in the interior of the
earth
• P-Waves - Travel through any medium (solid
or liquid) and reach the seismic station first
• S-Waves - Travel through solid material only
and are slower to reach the seismic station
• SURFACE WAVES - Travel along the surface
of the earth
• Love Waves - Moves the ground from side to
side
• Rayleigh Waves - Travel slowly and make the
ground move like the waves on a ocean or
roller coaster
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• Epicentre point on the earths surface
directly overtop of the focus
• Focus is where the movement takes
place in the lithosphere
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• Magma pushes through the centre of the
ridge
• As the magma/lava solidifies moves the
existing rock outwards
• Connected to the other ridges in the oceans
• Convection currents in the asthenosphere
help to contribute to motion that sets up plate
movements
• Plates are both oceanic and continental so
when you’re pushing one your pushing the
other
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• Convection Currents - Take place in the upper
mantle (asthenosphere)
• They operate much like boiling water or pasta
• Heats up to surface, cools off and falls back
to bottom, where it then heats up and repeats
the process
• Think about laying a piece of toast on top!
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Location of Oceanic Ridges
Sea floor Spreading
Continental Shelves
Seismological evidence (Quakes)
Movement of crust caused the crust to
crack forming plates
• Magnetism
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• Pacific Plate
• Subducting under the surrounding
continental plates
• In theory the plate is getting smaller
• N/A and Asia will collide (In theory)
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• Divergent (Mid Atlantic Ridge)
• Convergent (India and Eurasian Plate Himalayan Mountains)
• Transform aka Strike Slip (San Andres
fault)
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• Mountain Building - Orogenic Process
– Folding, Faulting, Volcanism
– Folds upwards as the plates collide
– Occurs when rocks pull apart and/or
fracture
– Volcanism molten rock reaches the surface
forming volcanoes and new rock
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Strike Slip
Subduction Fault
Extention Fault
******Collision Fault
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• Stratovolcano aka composite cone
• Layers of Rock and Ash
• Branches of magma flows off the main
conduit - Fissures - Harden to create even
more pressure
• When an explosion takes place they can reactivate old fissures and explode an entire
side of a mountain causing great damage
• Pyroclastic Flows are created as a result
– Super heated ash debris moving downslope a a
very quick speed
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• Hot spots in the asthenosphere
• Weaknesses in the crust
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• Pyroclastic Flow - Landslide of Ash,
rock and hot gases at 2000oF
• They are unpredictable an often more
deadly than an actual volcanic eruption
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• Scientists can determine the age of
rocks on both continents and in the
ocean
• Found continental rocks were older
• Ocean floor and conveyor belt
movements - New rock forms at the Mid
Atlantic Ridge(200 Million years old,
Pangaea Break up
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• Review the Mid-Atlantic Ridge Profile
and reading
• Be aware of the continental margin
features, Mid-Atlantic Ridge shape
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• Tsunami’s are very destructive because they
are not just one or two waves crashing
ashore.
• Rather, a Tsunami is a surge of water moving
inland up to 2 - 3km
• They destroy everything in their path and
when they retreat they often carry many
things out to sea
• Formation…See pg 133 of text
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• Tokyo lies on overtop the boundary of 3 major
plates
• Earthquakes happen regularly and they are a
part of life there
• Buildings are often built out of steel that can
bend and contort as an earthquake shakes
• Also the foundations of buildings are built on
shocks to absorb the shaking
• Lastly building are not built out of rigid
concrete as they cannot withstand shaking
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• Subduction is what causes Mega-Thrust
Earthquakes
• Stick slip properties (the bending of the
continental landmass
• Earthquakes releases pressure and
snaps the continental plate back into
regular position
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• Volcanoes - Seismic stations to monitor
earthquake activity around the volcano
• Tsunamis - Early warning detection systems
in the Pacific
• Earthquakes - Seismographs to measure the
strength of quakes and GPS to monitor the
movement of tectonic plates
• Mass media - Warnings over the internet, TV,
Cell phones, Twitter etc. The word travels
very quickly