The Crust Is In Pieces

Question 1

Structure of Earth

Answer 1

. Crust
. Mantle
. Outer core
. Inner core

. Lithosphere
. Asthenosphere

Question 2

Lithosphere

Answer 2

The solid top layer of crust in which plates are formed. Consists of crust and upper mantle.

Question 3

Asthenosphere

Answer 3

Soft, plastic like rock in the upper mantle just below the Lithosphere.

Question 4

Convection

Answer 4

. Heat source - radioactive decay in the earth’s core (e.g. iron + nickel)
. Rising limb of convection current, heated rock in mantle rises as it is less dense
. Semi-molten rock spreads out carrying the above plate
. Direction of plate movement due to movement of convection current below
. Cools and sinks back down to be reheated

Occurs in inner earth cuz inner core is the hottest layer at around 5000-7000 C. Liquid molten so heat rises towards cooler mantle and crust. Rock in mantle less dense.

Question 5

Mantle plumes

Answer 5

. Large column of hot rock rising through the mantle

. The heat from the plume causes rocks in the lower lithosphere to melt.

Question 6

Earth’s heat source

Answer 6

. Earth was hot when it formed - heat leftover from when plant formed
. Rose from a cloud of gas + dust and planetesimals stuck together + heated Earth to molten space

. Earth is slowly cooling
. Close to steady temp as it makes heat in interior
. Producing almost as much heat as its loosing - radioactive decay, disintegration of natural radioactive elements inside Earth like uranium
. Process produces subatomic particles that collide with surrounding material inside the Earth, e grey motion converted to heat
. With r-decay there would be less volcanoes + earthquakes

. Seismic data reveals whether materials are solid, liquid or partially solid
. Laboratory data indicates at what temperatures and pressures the materials inside Earth should begin to melt.
. Earth’s core temperature is estimated to be around 5,000 to 7,000C - about as hot as the surface of the sun, but vastly cooler than the sun’s interior.

Question 7

How long did Wagener think the plate movement has taken since Pangea formed?

Answer 7

300 million years

Question 8

What was found when the mid-oceans were mapped?

Answer 8

. Molten rock rises, spreads and freezes
. Both sides are fleeing
. Plates are being pulled apart
. Rock on both sides are symmetrical either side of ridge

Question 9

What did Wagener initial struggle to explain?

Answer 9

The pull and the push - he knew they had moved but not why

Question 10

As well as climate and landscape what else proved the theory?

Answer 10

Similar fossils on both sides of the major ocean

Question 11

When it refers to the crust being in pieces what are these ‘pieces’ ?

Answer 11

Tectonic plates

Question 12

In relation to the mid-ocean ridge where is the oldest material?

Answer 12

New material is constantly produced at the mid-ocean ridge and takes the magnetism of the Earth at that time. Because Earth’s magnetism randomly flips every now and again we can see a striped pattern in magnetism and match it to age. This is possible due to the sea-floor spreading process

Question 13

Paleomagnetism

Answer 13

The process of material pushing out from the ridge is known as ridge push.

Question 14

Subduction zones

Answer 14

At subduction zones gravity ‘pulls’ the ocean plate down into the mantle. This destroys crust material and keeps the Earth in shape

Question 15

Slab pull

Answer 15

The pull of gravity on a plate that is being subducted