My Notes for Unit 3

Question 1

What does lava help to tell us?

Answer 1

What is down deeper

Question 2

Composition of meteorites is like that of___.

Answer 2

Earth

Question 3

Earth is made of___stuff inside, ___stuff outside.

Answer 3

• heavier

- lighter

Question 4

What is gravitational differentiation?

Answer 4

• iron and nickel
• sink down to the bottom
• density separation of elements
• heavier elements sink down

Question 5

What percent of Earth’s core is iron? Nickel?

Answer 5

• Iron = 93%

- Nickel = 3%

Question 6

What is silica?

Answer 6

silicone and oxygen

Question 7

What is silicate

Answer 7

silica and some other element

Question 8

What is the mantle almost entirely made out of?

Answer 8

silicate minerals

Question 9

What happened to the primitive crust?

Answer 9

We don’t have any of the primitive crust left. Buried by geological processes.

Question 10

What is the continental crust the result of?

Answer 10

Ca, K Na, Al (silicates)

Question 11

What is the oceanic crust made out of?

Answer 11

Fe, Mg, Ca, Al (silicates)

Question 12

What is the inner core made out of?

Answer 12

Solid Earth: Fe, Ni

Question 13

What is the outer Core made out of?

Answer 13

Liquid Earth: Fe, Ni

Question 14

What is mantle made out of?

Answer 14

Fe, Mg, Ca, Al (silicates)

Question 15

Solidus?

Answer 15

The temp at which melting begins A mixture of solid and liquid.

Question 16

What is the solidus controlled by?

Answer 16

controlled by lithosphere and pressure

Question 17

Why are planetary bodies hot inside?

Answer 17

1) Gravity (accretion pressure and impact of asteroids and comets)
2) Atomic Fission (breakup up of atomic isotopes)

Question 18

What is isostasy?

Answer 18

The lithosphere-crust and upper mantle is not actually sitting on the mantle–it is floating on it. Rocky crust is floating on lithosphere (floating equilibrium).

Question 19

What happens when a glacier flows on X-Sections (isostasy)?

Answer 19

When a glacier flows, it is the additional weight added to the crust by the weight of the glacier that creates floating. When a glacier melts, the land surface will come backup. depresses lithosphere into mantle.

Question 20

What happens after volcanism?

Answer 20

Ground will “rebound” after volcanism ceases for good and erosion strips away the top.

Question 21

What are the two different ways to discuss the outer part of Earth?

Answer 21

1) Chemical composition (rock type)

2) Physical strength

Question 22

What are the two crustal parts?

Answer 22

continental and oceanic

Question 23

What is the depth of the continual crust?

Answer 23

35 km depth (shallows towards ocean)

Question 24

What is the depth of the oceanic crust?

Answer 24

8 km depth (close to ocean)

4 km depth (rocky depth)

Question 25

What is the contact between mantle and base of crust called?

Answer 25

Moho

Question 26

Physical strength of outermost part of mantle is similar to___ ___.

Answer 26

crustal ricks

Question 27

What is under the lithosphere?

Answer 27

A unit that is physically weak called the asthenosphere.

Question 28

What is the asthenosphere?

Answer 28

weak sphere

Question 29

What is the lithosphere?

Answer 29

strong sphere

Question 30

What makes up the upper mantle?

Answer 30

asthenosphere and lower part of lithosphere

Question 31

What is the weakest part of the earth system?

Answer 31

asthenosphere.

Question 32

What is broken into tectonic plates?

Answer 32

lithosphere

Question 33

What do the tectonic plates move over?

Answer 33

the asthenosphere

Question 34

What is the material the lithosphere is composed of?

Answer 34

rock

Question 35

When were the major ice ages (4 of them)?

Answer 35

~600-700 (Paleozoic) ~450 (Paleozoic) ~300-250 (Mesozoic) ~3-now (Cenozoic)

Question 36

What is planetary magnetism off-set with?

Answer 36

Geographic poles (spin axis), but this is temporary

Question 37

Magnetic poles___with time.

Answer 37

shift

Question 38

What is magnetic polar shift?

Answer 38

The fact that magnetic poles shift several km/year (irregular), so their positions move over the globe (mainly polar regions) a considerable amount.

Question 39

Is the strength of magnetism set or varied?

Answer 39

Varied, but may not drop to zero

Question 40

Is the strength of magnetism increasing or decreasing at present?

Answer 40

decreasing

Question 41

What is magnetic polar reversal?

Answer 41

After weakening it becomes chaotic (theory), then builds back up...sometimes in the opposite sense.

Question 42

Earth's magnetic field varies in___[___] by perhaps___% over a time scale of decades to ventures. Does___appear to drop to zero.

Answer 42

vaires - intensity - 50 - not

Question 43

What is polar shifting?

Answer 43

the poles "walk"...variable rate (~50 km/year for the past 20 years).

Question 44

What is the average position of the poles for that past are thousand years?

Answer 44

At the spin axis.

Question 45

On average, how ofter does the vector reverse with magnetic polar reversal?

Answer 45

3 times per million years

Question 46

Magnetism of planet Ear is___to what it would be if in the centre of the earth ere was a magnet.

Answer 46

similar

Question 47

What happens with basalt from volcanoes and Earth's magnetism?

Answer 47

Basalt lavas always have a small amount of magnetite (FeO4). When basalt is still hot, not affected by magnetic field (1000 degrees C). When it reaches 700 degrees C, it becomes affected --> called Curie Temp.

Question 48

What are magnetic pole position sin northern hemisphere based on?

Answer 48

The remnant magnetism in igneous rocks for the last 20 ma.

Question 49

For how long has magnetic polar reversal been going on? How long do we have detailed measurements for?

Answer 49

at least the last 3 Ga -- but we have detailed measurements only for the last ~160 Ma

Question 50

Magnetism will always be appalled with___ ___ ___.

Answer 50

force field lines

Question 51

What could be the 3 causes of Earth's magnetism?

Answer 51

1) flowage of Fe material in liquid core (convective flow) 2) differential rotation -- spin - inner solid core spins slightly differently than rest of core because of liquid core. 3) force field follows ~ spin axis (self-exciting organism)