Flashcards
Test 1
Cards in this deck (87)
- 1What are the 7 Earth systems cyclesClimate cycles - climate change
Sea level cycles
Atmospheric circulation
Oceanic circulation
Hydrologic cycle
Plate tectonic cycle
Rock cycle - 2What piece of technology records the way seismic waves are transmitted through the earth's interiorSeismographs
- 3Why does the earth have magnetic poles?the inner core spins slightly faster than inside the liquid outer core
acts as an electric generator to produce a electromagnetic field that extends into space - 4How does the earth work?The outer part of the earth moves a few cm per year
driven by a solid convection in the earth's interior - 5How do we know the sea floor is spreadingthe pattern of magnetic anomalies parallel to the rift valley of a mid-ocean ridge
- 6Are earthquakes and volcanoes distributed evenly?Earthquakes and volcanoes occur mostly at the plate boundaries
- 7What drives plate tectonics?Mantle Convection
Heat and hot rock circulating through mantle
cold, dense slabs are recycled back into mantle for subduction - 8What is a rock?Made up of groups of minerals (ign/ met) or particles of other rocks (sed)
- 9What is a mineral?naturally occurring solid
specific chemical composition
repeating structure of atoms - 10What is the continental crust made up of?Granite
- 11What is the oceanic crust made up ofBasalt
- 12What creates mountain rangesContinental collisions
- 13What are primary waves (P-waves)Push/pull effect
Compresses and expands particles
Fastest wave
Travels through any medium
Faster in dense rocks i.e. faster at depth
- 14What are secondary waves (S-waves)Side to side movement at right angles
Slower than p-waves
Travels only through solids - 15How is wave energy reflected and refractedRef- waves refract away from interface if material it enters causes slow movement of waves
- waves refract towards interface if the material causes speed up of waves - 16What does the mantle consist mostly ofPeridotite
- 17what occurs with depthvelocities increase with depth
- 18At approximately 100 to 200km depth what happens to the peridotitethe pressure and temperature makes the peridotite melts a little (<2%)
due to slow seismic wave travel, a low velocity
this weak zone causes the movement of oceanic plates - 19what is the mantle density in the crust, mantle, upper mantle, transition zone and the lower mantle3.5gm/cm3
5.5gm/cm3
400km
670 km
2900 km - 20How dense is the oceanic crust7-10 km
- 21How dense is the continental crust35-40 km
- 22WCrust-mantle boundary
- 23How dense is the inner core10-13 gm/cm3
- 24How dense is the outer core2900 to 5155 km
- 25what is the outer core compositioniron alloy
- 26How dense is the inner core5155 km to 6371 km
- 27What is the composition of the inner coresolid iron alloy
- 28What generates the magnetic fieldconvective fluid motion in outer core generates magnetic field
movement of conducting iron generates magnetic field
radioactive heating and chemical differentiation - in state of convection - 29Wrecord of ancient magnetism preserved in rock
- 30what is the orientation of the magnetic force fieldperpendicular to the earth's surface at poles
field points downwards in the Northern Hemisphere and vice versa in the south - 31What are the two components of rock magnetismdirection of magnetic 'pointing'
inclination with the earth's surface - 32what does the magnetic record give and indication ofwhere the rock was on the surface when it was magnetised
- 33Certain minerals are ...magnetic
when cooling, magnetic minerals alight with the magnetic field
when cooled below curie point (i.e. 580º for magnetite) grain alignment freezes in - 34What has occurred with the earth's polarity during historymagnetic field has reversed polarity at various times
can occur in 10's to 1000's of years - 35What are positive anomalies due topresence of rocks with 'remnant' magnetism of normal polarity
- 36what are negative anomalies due topresence of rocks with remnant magnetism of reversed polarity
- 37what will be the effects of a future magnetic reversalSolar wind hits earth more intensely
increased radiation = skin cancer
disaster unlikely - 38What does the rock found in the oceanic showpreserved record of earth's magnetic polarity at the same time the crust formed
- 39What does a collisional convergent zone begin asAndean type
- 40What occurs at continent-continent plate boundariescrustal shortening and thickening
- 41what are the two types of convergent plate boundariessubduction zones
collisional zones - 42what happens to the lithosphere at subduction zonesLithosphere is consumed
surface area of earth remains constant - 43what is a continental riftdivergent boundary on a continent
e.g. the red sea rift - 44What happens to the oceanic crustOld is cold and cold is dense
after 80Ma crust wants to subduct
destructive plate margins - 45What happens at convergent plate boundariesTwo plates collide
one oceanic plate bends and sinks into asthenosphere (if one is oceanic)
lithosphere is more dense than asthenosphere - 46What are the three types of convergent boundariesocean-ocean
ocean - continent
continent-continent - 47What is a Viscosity boundary
- 48What is the crust composed ofcomposition: felsic, intermediate, mafic igneous, sedimentary and metamorphic rocks
- 49What is the age of the crust0-4 billion years
- 50What are the properties of the continental crustthicker, less dense, heterogeneous, old
- 51From the oceanic crust, what is the depth of the mohoapprox 7 km
- 52What is the composition of the oceanic crustmafic igneous rocks (basalt and gabbro)
thin layer of sediments on top - 53what is the approximate age of the oceanic crust0-200 million years
- 54What are the properties of the oceanic crustthin, more dense, homogeneous, young
- 55How would you describe the movement of transform platesslide past each other
- 56How does a divergent boundary startlithosphere stretches due to rifting
continental rift is a belt or zone where the rifting occurs
if rifting is successful, lead to formation of ocean basins - 57How does a subduction zone begin and stop
- 58Where do the deepest and the largest earthquakes occurat subduction zone
- 59Where do volcanoes originatesubducting plates
- 60What are plumesmantle convection
rising from core-mantle boundary - 61What is a slab pull?derived from negative buoyancy of slab
weight of slab pulls plate to subduction zone
resisted by viscous mantle - 62What is trench suctionslab drags against viscous mantle, causes flow in mantle wedge towards subduction zone
flow sucks in nearby plate i.e. pulling plug of bathtub - 63What is slab rollbacksmall scale convection on back side of subducting slabs
- 64WHat are plate tectonic resistive forcesexerted on overriding plate
results in sheer stress distributed on subduction thrust interface - 65What is a basal sheer traction (mantle drag)resistance associated with mantle/lithosphere interface
- 66What can you construct if you correct local movementsglobal hotspot reference frame = absolute plate motion w.r.t core mantle boundary
- 67What is important factor in the thermal cycleupwelling in mantle plumes
- 68What can mid-ocean ridges and sea floor spreading be a factor ofpassive phenomena
- 69What do LLSVPs sit aboveplate motion and plate force divergent zones, edges mark hotspot sites and kimberlite magmatism
- 70What drives plate motionridge push
slab pull
basal drag
mantle resistance/friction - 71WMantle plume activity
Volcanoes are not necessarily near plate boundary - 72What does convective motion requireheat source
heat from earth comes in two ways:
radioactive decay
residual heat - 73What is a rock?Naturally occurring
Aggregate of minerals - 74What is an igneous rockcrystallisation from molten rock rising from earth's interior
- 75What are sedimentary rocksaggregates of sediment
chemical (precipitated from water)
organic sediments e.g. coal, oil - 76Wchanged from one form (igneous or sedimentary, metamorphic etc)
exposed to intense heat, pressure, hot fluids
growth of new minerals which exist in new pressure and temp conditions - 77What is the earth's crust composed ofigneous rock
- 78Where does igneous activity primarily occurat or near tectonic plate boundaries
- 79What types of rocks are formed at divergent boundariesmafic igneous
- 80What type of rocks form at convergent boundariesintermediate to felsic igneous rock, is due to the partial melting which produces magmas
- 81What rock is found at divergent plate boundariesIgneous rock i.e. Basalt
Metamorphic rocks from heated water - 82Where else can igneous activity occur and whyInside plates
rising mantle plumes produce hotspots & volcanoes which rise through oceanic or continental crust
i.e. Hawaii - 83All three rock types form at convergent plate boundaries, how is sedimentary rocks formsediments compressed and cemented
- 84How are metamorphic rocks formedcompressed, heated and change minerals
DO NOT MELT - 85How are igneous rocks formedWhen rocks melt, magma is formed, rises, cools and crystallises
- 86What occurs at transform plate boundariesMid ocean ridge is formed at transform faults
shallow earthquakes generated
igneous activity is rare
rocks can be any of the three types - 87How is the rock cycle integrated into plate tectonics
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- Tertiary Geology: Earth's Interior Flashcards on Test 1, created by Olivia Gniadek on 08/08/2018.
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- Olivia Gniadek
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