Chapter 4 : Heat Flow

Question 1

What earth processes are controlled by transfer/generation of heat?

Answer 1

Tectonics, mountain building, volcanoes, metamorphism

Question 2

What affects the temperature change in a length of time?

Answer 2

Heat flow across a surface, heat generated within volume, thermal capacity, motion of volume to regions of different T

Question 3

What can cause advection of temperature?

Answer 3

Erosion/depostion can change location of volume element relative to earth’s surface, volume element can move as part of convection from temperature-induced density differences

Question 4

Geotherms

Answer 4

Temperature-depth profiles

Question 5

How should ocean depth change with age and why?

Answer 5

Increase, lithosphere cools, contracts, becomes denser

Question 6

Convection in fluids

Answer 6

Occurs when density distribution causes gravitational instability

Question 7

What causes density disturbances

Answer 7

Chemical stratification (outer core) or temperature differences (mantle)

Question 8

Rayleigh number

Answer 8

A measure of the instability of a layer of fluid due to differences of temperature and density at the top and bottom

Question 9

Critical Rayleigh number

Answer 9

Above this number, convective flow is sustained

Question 10

What affects Rc?

Answer 10

Fluid, boundary conditions: constant T or constant Q at upper/lower surface, upper/lower surface can be free or rigid boundary