Unit 2 Review and Solutions
1• 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
2• 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)
4• 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
5• 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
7• 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
8• 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 re-
activate 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
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