Please use the following information to answer questions' I'll provide to you after:

5/6 Understanding Landscapes

The Earth has 3 different layers essentially:

	-Crust - mostly composed of silica, 50-75% of the crust has silica in it
		-Because silica is lighter in weight and lower in density it tends to float on the surface

	-Mantle - composed mostly of iron and magnesium, heavier/denser materials so they sink

	-Core - Mostly composed of iron, nickel, and sulfur. 
-The core of the earth has so much weight pushing down on it that they elements start to go through nuclear fusion
	-This fusion is the earths internal energy source

Physical properties:	

CORE
	-Inner Core:
		-Solid ball
		-Density of the inner core generates our gravitational field

	-Outer Core:
		-Same chemistry as inner core
		-It behaves differently than inner core
		-The pressure is slightly less so it behaves as liquid metal
		-Fast spinning Iron, Nickel, Sulfur material
		-Dynamo that creates magnetic field around earth
-This magnetic field protects us from the most intense radiation from the sun
-Aurora Borealis is the interaction between our magnetic field and the sun's radiation

	-Mesosphere

MANTLE
	-Mesosphere:
		-middle layer, lower mantle
		-Convection happens here because closer to the core it heats up and raises up toward the asthenosphere it cools down and lowers back toward the core
-Asthenosphere:
-This name is greek, stands for Greek
-Plato like plastic
-Lubricating layer
-Allows layers above to float on layers beneath it
-Lithosphere:
		-The crust we live on

 -Our instruments have only gone down 7.5 miles deep into the earth
-We have to use proxy data to figure out whats going on underneath
-We use meteorites as proxy data to give us an idea of how these planets formed and were destroyed

-Volcanoes like hawaii have a very deep root and come from inside the mantle
	-We use that as proxy data as well
-We also use seismic waves from earthquakes to take a picture of the interior of the earth

P-waves - primary wave
	-Moves side to side
	-This is the wave we hear
	-It is faster than the S-wave
	-Compressional waves
	-Sound waves lower frequency than we can hear

S-Waves - Secondary wave
	-moving up and down 
	-undular
	-The wave we feel

-We use these waves to read the interior of the earth using refraction
	-In a solid these waves travel very quickly and efficiently
	-Once the density changes the speed and direction of the wave changes
	-Speed up when they move through denser material and slow down when they move through more liquid material
-The waves stop or slow down once they hit the liquid outer core
-S waves stop in liquid
-P waves slow down in liquid
-Only p waves can travel through core
-These waves are picked up by various stations around the earth

“Whats the primary wave that we see into the interior of the earth?” 
	-Seismic energy, P and S waves
	-We use chemistry and physics to peak into the interior of the earth


CRUST;
	-Continental Crust:
		-Felsic
		-Light colored
		-Low density
		-Floats
	-Oceanic Crust
		-Mafic
			-Magnesium and iron rich
		-Dark Colored
		-Higher density
		-Originates in mantle itself
		-Sinks

Things to keep in mind:
	Lithospheric Plates
		-Large rigid fragments of oceanic or continental crust and upper mantle
		-Move over asthenosphere
		-
	Asthenosphere
		-Plato that allows the crust to move on top
	
Mohorovicic discontinuity (MOHO)
	-Density has a marked difference between the crust and mantle
	-Continental crust looks like an iceberg
		-Thick and lightweight
		-25 miles thick at its thickest
	-Oceanic crust is much thinner
		-Dense, composed of iron and magnesium coming from mantle
		-3-5 miles deep at its thickest
Continental Shields
	-Large stable low relief expanse of land
	-Old metamorphic igneous rock
	-North American Shield
		-Canadian(Laurentian shield)
			-4 billion years old
		-Ancient life is trapped in the rocks in these shields
Topographic Relief
	-Vertical difference between highest and lowest elevation
	-High relief
		-large difference from high to low elevation
		-younger land, tectonic forces are very active
		-Creates mountains and hills as plates crunch together
		-Very active landscape
	-Low relief
		-Small difference
		-older landscape that broke back down to flat surface over time
		-Not a lot of tectonic activity
Orogenic belts
	-Series of linear mountains
	-Zones of higher relief
	-very young features

Weathering
		-Physical, chemical breakdown of rocks
		-Landslides
Erosion
		-Removal of weathered rocks


Plate Tectonics and Regional Features
What was Wegener’s supercontinent?
-Pangea
-
What was Wegener’s evidence for continental drift?
-The continents looked like puzzle pieces
-Fossil similarities of flora and fauna found on other continents
-Rock similarities and mountain chain similarities
-Paleoclimatic evidence such as glacial deposits at the Equator. Coral reefs in Antarctica


How was Wegener's theory incomplete? 
-he doesn’t know how or why they move


-Paleomagnetism -
-seafloor spreading -
-Plate boundaries - earthquakes occur along fault lines


Who was Harry Hess and how did his theory add to Wegener's theory?
-A geologist that joined the US navy in 1960’s
-He was using sonar on a ship (minesweeper)
-Maps out the ocean floor
-Discovers seafloor spreading through mid ocean ridges
-Continental Drift set the foundation and Harry Hess seafloor spreading filled in the gap
(gave the cause) - due to convection in the mantle
-Explain tectonic theory on the quiz
	-discuss wegners continental drift and hess’s seafloor spreading together
-Ongoing area of research


Which boundary creates crust? Which boundary destroys crust? Which boundary does neither?
-Transform boundary - San Andreas Fault(Pacific/North American plate sliding past each other)
	-Two boundaries slip past each other
	-Neither creates nor destroys crust
	-shallow focus earthquakes


-Divergent boundary - point of creation of new crust

-Plates moving away from each other due to convection in the mantle. This is constructive. Represented by Mid-ocean ridge. Boring area with very low earthquakes and volcanic activity. Forms new crust
	-Atlantic ocean is the youngest ocean, 200 million years old
	-Rift-valley
 -Magma starts pushing up into the bottom of the plate and causes the plates to begin moving apart. Starts forming a valley and it gets lower and lower. It then gets below sea level and fills with water creating a proto ocean. 
-A mid oceanic ridge then begins to form and the plates start drifting farther and farther apart. A mature ocean is then formed.
-Iceland has an example of this rift valley formation



-Convergent boundary - plates coming head on into each other
	-Collisions between plate
	-Destructive
	-Oceanic-continental - oceanic plates have different density than continental(iron and magnesium.	
		-Continental plates are light and made of silica, they float
		-Oceanic plate sinks below continental (SUBDUCTION)
		-massive earthquakes and volcanic eruptions
		-the material melting beneath the surface is less dense and pushes up into the crust creating volcanoes
	-Oceanic-Oceanic - oceanic crusts can have subduction
				-one crust can be denser when it’s older and denser
				-the younger will be less dense/hotter and dives down
		-Subduction results in undersea trenches
		-Deep and shallow earthquakes
		-island volcanic arc
	-Continental-Continental - No subduction
		-build huge mountain ranges
		-Volcanoes are rare
		-SHallow earthquakes relatively common, massive earthquakes



Notes:
-Wegener was a climatologist 
-He was german during the wrong time, he wasn’t a geologist, and he could not produce a plausible mechanism as to how the continents drifted
-James dana had the idea of Global Contraction Theory which was widely accepted at the time
-The Appalachian mountains on the East Coast and the Atlas Mountains in Morocco North Africa are the same mountain chain. They have the same chemistry
-Antarctica has evidence of Coral Reef
-Mantle rock is iron and magnesium

-Divergent boundaries create more earth and convergent(subduction) boundaries destroy the old crust by melting it beneath the surface.

-Cascadian mountains are a subduction zone
-Cascadian subduction zone hasn’t had a massive earthquake since the 1700’s

-They’ve found oceanic fossils in the himalayas


5/18 Volanoes, Deformations, and Earthquakes

What's the difference between lava and magma?
-Lava is above ground magma is below ground
How does viscosity of lava play a role in the development of volcanic types?
	-Viscosity determines how the magma flows, 	
-low viscosity it typically forms shield volcanoes
-high viscosity it will typically forms Composite/Strata volcanoes or dome volcanoes


What kind of volcanism is most associate with a divergent boundary versus a convergent boundary? What are the characteristics of the characteristic type of volcanism at each boundary?
	-Fissure volcanoes are typically seen at divergent boundaries
		-Low silica, high temp
		-Basaltic, mafic
		-low gas
		-tear in the ground
	-Shield volcanoes are typically found at hotspots or divergent boundaries
	-hotspot
		-Low silica high temp magma
		-Gentle Giants
		-Mafic -basaltic, iron magnesium
		-wide
		-not a lot of gas
		
	-Composite or Stratovolcanoes occur at convergent boundaries
		-High silican, low temp
		-Their lava comes from much higher up in the mantle 
		-Felsic
		-Lots of gas trapped
		-Emit higher silica lavas(Andesite lava)
		-Very violent eruptions
		-Steep sided symmetric volcano
		-Pyroclastics mix with lava flow produce steep slopes
			-lava holds it together
		-source material doesn’t come from deep in the mantle
		-Material comes from plate convergence
		-Picks up more silica making it thick and plug it up
		-Traps in gas and makes things more violent
-Lava Domes
- Masses of very viscous lava
-volcanic plug
	-form inside composite volcanos
`````````````````````````````````````````````````````````````````````````````````````````````````


Diastrophism - deformation of the earths crust
	-Two types, Folding and Faulting
	-Folding is temporary deformation
	-Faulting is permanent deformation
Folding - results when rock is subject to lateral compression
	-Can take place on any scale
	-Two types - Anticline/upfold, can be forced to have reverse orientation an overturned fold. Hills, we have oil in them here in OC
			-Syncline/downfold - valleys
What kind of faulting is most associated with each boundary type?


Four primary types of faults
	-Normal fault - Divergent boundary
		-Mild earthquakes
		-5 magnitude earthquakes
	-Reverse Fault - Convergent boundary
		-6-7 earthquakes, mild to moderate
		-Similar to Thrust fault, just vertical movement
	-Thrust Fault - Convergent boundary
		-magnitude 9 or bigger
		-Big earthquakes
		-Similar to Reverse fault just horizontal movement	
		-Sometimes don’t show on the surface
		-Scary because we don’t know they’re there


	-Strike-slip fault - transform boundary
		-Mostly on the surface
		-a lot of shaking
		-long faults
		-between 6-8 sized earthquakes
		-Linear Fault trough
			-Small depressions in the trough known as sags
		-Horizontal displacement
		-Offset drainage channel


What kind of mountain building occurs at a divergent boundary versus a convergent boundary? Give a real example of each?




Which boundary type generally creates the largest earthquakes? Why?
-Convergent boundaries because they produce the most force and when they have enough mass build up the most pressure before releasing. Ex Thrust faults


What's a tsunami and how does it form?





Isostacy- the continents are very buoyant 
	-the equilibrium between the earth’s crust and asthenosphere
	-isostatic rebound
	-Erosion causes the weight in the area to lessen and allowing the plate to rise
-Mountains that grow like the himalayas push down into the mantle due to the weight of all that rock

-Removing ice also causes the plates to rise
	-ex greenland losing it’s ice is causing earthquakes

-Removing groundwater can cause the ground to move
-Damming rivers can cause the ground to move


Evolution of Continents
-Terranes
	-Chunks of land consistent in age, rock type, and structure

-Accretion
	-The process of adding pieces of land to a continent
	-being glued on

-Suspect Terrane
	-Also called exotic terrane
	-piece of landmass that is vastly different from its surrounding rocks

-Accreted Terranes
	-Piece of lithosphere carried by a plate that eventually collides and fuses(Accretes) with another plate

	Additions:
		-Mantle plumes
			-Localized hot areas not associated with plate boundaries
			-Move with the plate so it will eventually become inactive
			-Hot spot trail, hawaiian islands
Properties of Magma
-Lava is Magma exposed to the atmosphere

Viscosity - a fluids resistance to flow
	-Some magmas have higher viscosity than others
	-Higher viscosity magmas typically have higher silica content
		-produce explosive eruptions
		-pyroclastics - solid chunks erupted from a volcano
	-Basaltic lavas have low viscosity and have effusive eruptions

Volcanic Activity
-Relatively temporary features on the landscape
-A lot of earths water originated from water vapor from volcanic eruptions
-Magma contains major elements required for plant growth
-provides soil fertility

Distribution of Volcanic Activity

*Typically occur in divergent boundaries

-Six type of volcano
	-Fissure volcano(divergent boundary)
		-tear in the ground
		-Low silica high temp magma
-Shield volcano(Hawaii)
	-hotspot
		-Low silica high temp magma
		-Gentle Giants
		-Mafic -basaltic, iron magnesium
		-wide
		-not a lot of gas
-Composite Volcano
		-High silica, low temp
		-Felsic
		-High gas, very explosive

Volcanic Peaks
-Composite(strata) volcano
	-Emit higher silica lavas(Andesite lava)
	-Very violent eruptions
	-Steep sided symmetric volcano
	-Pyroclastics mix with lava flow produce steep slopes
		-lava holds it together
	-source material doesn’t come from deep in the mantle
	-Material comes from plate convergence
	-Picks up more silica making it thick and plug it up
	-Traps in gas and makes things more violent
	
-Lava Domes
- Masses of very viscous lava
-volcanic plug
	-form inside composite volcanos
	
	-Volcanic Hazards
	-Volcanic gases 	
		-acid rain
	-Lava flows
	-Eruption clouds
		-Volcanic ash is actually obsidian, pulverized volcanic gas
			-Does big damage to your lungs
	-pyroclastic flows
		-avalanche of hot gases and material up to 100 mph
	-Volcanic mud flows(lahar)
		-Result from heavy rain or snow melt during an eruption
Hotspots
	-Intra-plate volcanism occurs over a stationary hotspot
	-Hawaii and yellowstone 
	-Lithospheric plate moves over the hot spot producing an active volcano
	-Plate moves off the hot spot it produces a long chain of mostly extinct volcanoes

Fault - a crack in the earth that moves
Joint - just a crack in the earth, no movement


Dipslip faults - vertical motion faults


Hanging Wall - Block of rocks above the fault line
		-gold and silver were along these faults
		-Water deep in the earth travels up the faults and brings the ore with it			-The wall that moves
Footwall - Blocks of rocks below the fault line
		-Stable wall


Mercali scale is the more relavent scale now
	-it gives us the amplification