System Earth Ch 07

Question 1

seismology

Answer 1

the study of earthquakes and related phenomena

Question 2

earthquakes

Answer 2

the rapid release of stored energy as a result of quick movement between rocks. Can be as deep as 700km below surface

Question 3

fault

Answer 3

fracture caused by an earthquak

Question 4

surface waves

Answer 4

travel along the earth’s surface and transmit earthquake energy

Question 5

body waves

Answer 5

travel through the earth and are categorised as P or S waves

Question 6

P waves

Answer 6

longitudinal
they can travel through the earth’s core but also through the crust. They provide the estimate for how big the core is

Question 7

S waves

Answer 7

are transverse waves. They cannot travel through the earth’s core. Can only travel through solids. The furthest they travelis 103 degrees from where they were emitted.

Question 8

mohorovcic discontinuity

Answer 8

difference in earth’s crust thickness

Question 9

continental vs oceanic crust

Answer 9

continental is thicker but less dense. They differ in chemical and meteorological compositions as well.

Question 10

igneous

Answer 10

cooling and solidification of magma. If this occurs below the earth’s surface, it is an intrusive rock

Question 11

lithification

Answer 11

conversion of loose sediment into rocks (sedimentary rocks who would believe it)

Question 12

sedimentary rocks

Answer 12

compacted sediment bigger than sand

Question 13

metamorphic rock

Answer 13

rocks that form under high pressure. As long as no melting is involved, it’s metamorphic

Question 14

major rock forming minerals

Answer 14

feldspars, quartz, olivine, pyroxene

Question 15

what type of rock covers most of the earth’s surface

Answer 15

sedimentary

Question 16

mantle

Answer 16

a seismic low velocity zone exists
mantle rotates in the same direction as the earth

Question 17

core

Answer 17

is made up of iron, nickel and ligth elements. It is much denser than the mantle, changing its seismic wave velocity. It is the source of earth’s magnetic field.

Question 18

earth’s magnetic field

Answer 18

in the core, like a dynamo, transforms energy into fluid motions. The liquid outer core convects and conducts electricity. The solidification of iron releases heat, allowing for a liquid iron core.

Question 19

mid ocean ridges

Answer 19

has a rift and is an indicator of seafloor spreading

Question 20

lithosphere and asthenosphere

Answer 20

upper crustal part of the lithosphere is brittle. Below this is the asthenosphere, a region of the upper mantle that acts more like a fluid than a solid. It is ductile.

Question 21

divergent margins

Answer 21

constructive plate boundary
rift vallyes, lava rises and cools, forming new land
triple junction is if there is a centre point of the margin

Question 22

convergent margin

Answer 22

destructive plate boundary. you get subduction of the denser plate and melting and slab pull and convection currents etc. the subducting plate creates deep sea trenches. you get a volcanic arc

Question 23

convergent margin oceanic vs. oceanic

Answer 23

same thing but it’s called a volcanic island arc. Marianas trench is an example.

Question 24

convergent continental vs. continental

Answer 24

neither can be subducted so you get a separation of crustal poition of the lithospheric plate from teh mantle bbelow. Subduction of teh mantle part might happen whil the continental crust compresses and crumples. This results in mountain formation like when india collided with asia.

Question 25

transform margins

Answer 25

conservative plate boundary
lithosphere is neither created (extruded) or destroyed (subducted)

Question 26

transform faults

Answer 26

form at conservative plate boundaries, like san andreas fault

Question 27

what drives plate tectonics

Answer 27

heat from the earth
convection in the mantle
forces acting on plates

Question 28

how does radioactive decay come into plate tectonics?

Answer 28

the heat of decay results in warmth = energy

Question 29

potential heat sources

Answer 29

the heat in the core is from earth’s creation and this is transferred to the mantle

Question 30

convection in the mantle

Answer 30

occurs, maybe split into two

Question 31

forces acting on plates

Answer 31

gravitation force generated by high topography of a mid-ocean ridge on te rest of the oceanic plate.
slab pull - pulls opposite end of the plate into a subduction zone.
bending resistance
trench suction
friction
negative buoyancy

Question 32

rock cycle

Answer 32

starts with igneous, they are weathered, turned in to sediment and transported around. Chemically altered sometimes, they are deposited and accumulated in sediment accumulation. This happens in the sea and ocean. If they remain above sea and surface level, stuff is eroded again and then the cycle can start again. If not, metamorphic rocks form under high pressure.

Question 33

where does metamorphism occur?

Answer 33

deep in sedimentary basins along passive margis, in the defomred regions of active margins, or in the crust where igneous activity ingects into something cold.

Question 34

wilson cycle

Answer 34

continents assemble into a super continent and then break up again. This takes about 500 M y

Question 35

hypothesis of the wilson cycle

Answer 35

the continents come together where the mantle is cold and then they accumulate and provide a thermal layer. So the heat circulation changes and then