Phys Geology - Chapt. 15, 16, 17, 18, 19, 20, 21, 22, 24
Terms
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- Crest
- Trough
- Wave Base = 1/2 WL - Wave Motion
- Crest minus trough
- Wave Height
- Distance from crest to crest
- Wave Length
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- Energy Derived from wind
- Deep ocean waves there is little to no net foward motion of water
- Only _____ is transmitted in the Deep Ocean - Orbital motion, energy
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- _____ (Wave base intersects the shoreface)
- Wave velocity decreases
- Wavelength decreases
- Wave height increases
______ creates a water velocity resutling in erosion, transport, and depostion - Shallow water waves; Swash wash, Transition from Deep to Shallow Water waves
- Crashing wave in swash and wash
- Breaker
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- System of ______ and Back bays
- Energy is concentrated into the headland due to wave _____ (tendency of wave to bend and become nearly parallel to the coastline)
- Eroision and transport at the _____
- Depostion at the ______ - Headlands; refraction; headland; Back bay; Immature Coastlines
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______ causes an oblique swash-wash movement along _____
- Net foward motion is called ______ or Current (Current is parallel to the shoreline) - Wave refraction; shoreline; Longshore drift; Mature coastlines
- Offshore migrating current perpendicular to the shoreface
- Rip Current
- (Major source of Sediments for Shorelines and Barrier Islands are _____)
- Rivers
- Depostion along shoreface causes bar to migrate seaward
- Migration
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Rip-rap structures built perpendicular to shoreline to deflect longshore current
- Deposition on _____ side
- Eroision on the _____ - Jetties; upcurrent; downcurrent
- Rip-rap built parellel to the shore line causing depositon or infilling behind _______
- Breakwater
- ______ are the result of the Moon's and Sun's gravitational attraction
- Tidal Waves
- _______ result from seismic activity or movement of the seafloor
- Tsunamis
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- Warm water
- Shallow water
- Nutreint Rich water
- Oxygenated water
Charles Darwin and Theory of Reefs - Coral Reefs; reef requirements
- As the volcano subsides the reef keeps pace by growing from the top up
- Conversion of Fringing reefs to Atolls
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- Deserts ____ 30 degrees N and 30 degress south Latitude
- Due to high pressure cells in Troposhere - Along; Major Deserts of the world
- Rising air over mountains
- Wind Shadow
- Deflection of unbound surfaces (wind and water) due to the rotation of the Earth. Runs in circular path
- Coriolis Effect
- Removal of small grained sand and silt leaving a dersert pavement
- Deflation
- Polished desert rocks by the abrasion of the wind
- Ventifacts
- Large grained sand and gravel
- Creep and roll
- Bouncing of large grained sand
- Saltation
- Silt and clay causing dust storms
- Suspension
- Faces the wind
- Windward face
- Downwind side
- Leeward Slope
- Downwind depostion as a series of cross-beds due to sand cascading at the angle of Repose( steepest angle that loose sediment can obtain)
- Slip Face
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- Tips point downward
- Isolated dunes with limited sand supply - Types of Sand Dunes: Barchan
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- Tips point downwind
- "Unlimited" amount of sand supply - Types of Sand Dunes: Transverse
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- Blowout from storm winds
- Tips point upwind (on coastlines) - Types of Sand Dunes: Parabolic
- Conversion of Semi-Arid Land to desert due to human encroachment (not deforestation)
- Desertification
- Supercontinent of the Triassic Period. No explainable physical mechanism for the drifting of the continents
- Pangea
- Freshwater aquatic reptile
- Mesosaurus
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- Continental rifting in _____ plate boundaries
- Causes the formation of linear lakes in the ____ valley (Mesosaurus)
- Lakes give way to ____ seas
- Finally new oceans - divergent; rift; inland; Significance of Mesosaurus
- Part of Divergent plate boundaries. Is represented by the East African rift valley. A major elongate depression bounded by normal faults, where the entire lithoshere is deformed
- Continental rifting
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Later stages. Is the divergence of the Arabian plate and African plate
- Continental rifting
- Divergent plate boundaries - Red Sea Rift
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Initial stages. Seperates Somalian and African plates.
- Continental rifting
- Divergent plate boundaries - East African Rift Valley
- Rocks and Mountains are similar ( on both sides of the ocean)in age and compostion in opposite sides of the Atlantic oceans
- Rock Evidence
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- Early Mesozoic Glaciation when contenants were connected together in Pangea
- Distribution of Fossil Fuel - Paleoclimatic Evidence
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Field strain (measured along fault line) equals the Elastic limit of the rock (known for all types) the fault raptures causing an earthquake (relaese of seimeic energy)
- The theory that earthquakes result from energy released by faulting; the sudde - Elastic Rebound Theory
- Subsurface source of Earthquake
- Focus
- Surface point directly above the focus. Release of energy from the focus as seimic waves
- Epicenter
- Fastes wave, propagation of energy is in the direction of the wave. (horizontal)
- Primary (P) Wave
- Second fastest wave, (horizontal)propagation of energy is lateral to the wave
- Secondary (S) Wave
- Slowest wave, propagation of energy is vertical as rolling orbital waves. Up and down motion, the destruction wave.
- Surface Wave
- Distance to the Epicenter
- Intensity of an earthquake
- Unconsolated material suffers liquefaction (dewatering of the pore space)
- Type of Bedrock
- Energy release
- Magnitude of Earthquake
- Descrpitive (Qualitative) Scale from I to XII
- Mercalli Scale
- Absolute (Quantitative) from 1-10, Measured by the largest amplitude seismic wave from a seismogram recording. The seismogram is the recording. Seimograph is the instrument that records
- Richter Scale
- Exponential Scale 5 Moderate EQ
- Equal to an atomic bomb
- Exponential Scale 6
- Damage to well built structures (Base Line
- Exponential Scale 7
- Strong EQ equal to to 10x(#6)
- Exponential Scale 8
- Severe EQ Equal to 10x10x (#6)
- Exponential Scale 9
- Heavy Destruction equal to 10x10x10 (#6)
- _____ is determined by measuring the time differenes between the ____ converting time to distance, and _______ distances from ____ seperate seimosgraph stations
- Epicenter Determination; P&S; triangulation; three
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- Probable site for the next large sized EQ
- Frequence of 21 years
- Next quake due 1990
- 6.0 Sept 2004 - Earthquake prediciton; Parkfield California
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- Earthquakes occur along ______
- Most intense EQ occur along _______ Plate boundaries, i.e. Subduction zones
- Largest EQ have occured in the _______, the Pacific - Plate boundries; Convergent; Ring of Fire; Earthquakes and Plate tectonics
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- Velocity of Seimic Waves are dependent on the denisty of the Earth's layers
- S Waves are absorbed in liquids due to lateral shear, therefore, S waves are absorbed at the outer core boundary - Earth's interior
- Absence of detection of S waves on the opposite side to the EQ
- S Wave Shadow Zone
- Where do most earthquakes occur
- Convergent plate boundaries
- What happens to the S Waves at the outer core boundary?
- They are absorbed because the outer core is a liquid
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Two plates slide horizontally past each other
- Shearing Force
- Crust is not created or destroyed - Transform Boundaries
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Faults will offset the Ridge into a crooked appearing backbone
- Active displacement is _____ the ridge segments - Oceanic Ridge Transform Faults; between
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Faults where two plates slide past each usually involving at least one continental plate
- San Andreas fault (Pacific & North Amercian plate) - Continental Transform Faults
- Longshore drift is due to
- waves striking the shore obliquely
- An atoll normally evolves from a fringe or ______
- Barrier reef
- A cobble that has been polished and abraded by wind action is called a
- Ventifact
- Wind transports material by?
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- Rolling and sliding.
- Suspension.
- Saltation - What causes the migration of sand dunes?
- Erosion of sand on the windward side and deposition on the slip face.
- The steepest slope of a sand dune faces southwest, if the wind blows steadily from the
- Northeast
- What is the point on the Earth's surface directly above the place of origin of an earthquake called?
- Epicenter
- In P (primary) waves, the particles in a rock body move
- Back and forth parallel to the direction in which the wave travels
- Which seismic wave type cannot move through a liquid?
- S waves
- The most intense and Widespread zone of seismic activity occurs
- Along convergent plate margins.
- Distribution of Coral reefs is
- Between 30 degrees N and 30 degress S Latitude
- Net forward motion is called..
- Longshore drift or Current
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- Seperates the African plate from the Arabian plate
- Causes formation of the Dead sea and sea of Galilee - Dead Sea Transform System
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- Splits in the sea floor marked by Mafic (basaltic) volcanism and seismic activity
⬢ Forms _____ crust which is ____ than continental crust
⬢ Mild/Quiet Volcanism due to low Viscosity Magma
⬢ Divergent Plate Boundary - Oceanic Ridges; oceanic ; denser
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Shows the Rift Valley and Pelagic Sedimentation.
⬢ Pelagic Sediment thickens away from the Ridge
⬢ Oldest oceanic crust is away from the Ridge - Seismic Reflection profile
- ⬢ Youngest Rock in Iceland is located along the ridge (_____ of the island). The oldest is away.
- Observations in Iceland; middle
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⬢ French-American Oceanic Project
⬢ Alvin Submersible made a number of stunning observations of the Oceanic Ridge - Direct Observations of the Sea Floor
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Long Linear Extension Cracks, parallel to the ridge.
⬢ Due to plates pulling apart
⬢ Site of volcanic and geothermal activity - Fissures
- Results from subsea eruption of lava
- Pillow Basalt
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Geothermal vents located along ridge system.
⬢ Black due to dissolved mafic mineral content
⬢ Provide heat and nourishment to producers - Black Smokers
- ⬢ Divergent Plate Boundaries are marked by shallow-focused EQs of mild intensity
- Seismicity of Divergent Plate Boundaries
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⬢ Gravity Values ____ over the oceanic ridge
⬢ Heat Flow Values _____ over the oceanic ridge - Gravity and Heat Measurements; decrease; increase
- The theory that the continents move in relation to one another
- Plate movement (Continental Drift)
- What is the relationship of the palagic sediment?
- Pelagic sediment thickens away from the ridge
- Pacific Plate & North American plate
- San Andreas Fault
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- Plates move toward one another marked by (silicic) volcanism and high intensity seismic activity
- Forms Continental crust which is less dense than oceanic crust
- Explosive Volcanism due to high Viscosity Magma
- “Ring of Fire†- Convergent plate boundaries
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- Subduction
- Volcanism
- EQs
- Formation of Island Arcs
- Ex. Japan, Philippines, Indonesia - Oceanic Plate to Oceanic Plate
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- Subduction
- Volcanism
- EQs
- Ex., Cascades (Mt. St. Helens - Juan de Fuca & North American plate), Andes Mtns - S. Amercian & Nazca plate - Oceanic Plate to Continental Plate
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- No Subduction
- No Volcanism
- Earthquakes
- Ex. Himalayas - Continental Plate to Continental Plate
- - Formation of Contiental crust via Continental ______
- Accretion
- Series of Protocontinental Slabs (island arcs) that welded onto the N. American Continent
- Accreted Terranes
- What mechanisms for plate tectonics?
- Push, pull due to convection cells
- Convection cells within the Asthenosphere create a Ridge push and Slab pull
- Driving mechanisms for plate tectonics
- - Hotspots are due to relatively small convection cells that fracture the crust and cause Mafic (basaltic) eruptions (No divergence)
- Intraplate Hotspots
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- Hotspot remains ______
- The oceanic crust _____ across hotspot causing additional Islands to form - Hotspot & Island Chains; stationary; migrates
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- Note: Oldest Island
- Note: Active and Extinct Volcanoes
- Note: Direction of Plate movement. (Series of active is moving southeast then plate is moving Northwest) - Hawaiian Island Chain
- Example of interplate hotspot system
- Yellowstone Cauldera
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Fossil Fuels: Oil, Natural gas, and coal
- 85% of our energy needs
(#1 source of energy) - Nonrenewable Resources
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- US consumption leveled off in the late 70’s and early 80’s
- US oil production is declining
- Imported oil is increasing - Consumption-Production Cycle
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- Solar Energy
- Hydroelectric Power
- Wind energy
- Geothermal Energy
- Tidal Energy - Renewable Resources
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- Exponentially Increased in the Last Century
- Somewhat leveling off in last decade
- Current Population approximately 6 Billion - Human Population
- Current is parallel to the shoreline
- Longshore drift
- Coral reefs are located at the Distribution _____ 30 degrees N and 30 degrees South Latitude
- Between; Distribution of Coral reefs
- 1989 World Series earthquake happened where?
- San Francisco
- Liqiufaction earthquake was in ______
- Mexico City
- 3-D showing _____ nature of Mid-Atlantic ocean
- Complex
- Navaho Sandstone Zion National Park is an example of...
- Cross bedding
- What kind of tips point upwind on coastlines...
- Parabolic
- On irregular (immature) shore lines, the energy of a wave is...
- Concentrated mostly on the headlands by wave refraction
- Longshore drift moves water and sediment...
- Along the beach in a zigzag path
- In general, we can expect that on an irregular coastline...
- Headlands will be eroded and bays will be the sites of deposition
- In general, the dominant EROSIONAL landforms in desert regions are developed by...
- Running water
- Sediment on the ocean floor...
- Is thickest toward the subduction zone and thin or absent on the ridges