Study Flashcards
(36 cards)
1
Q
Continental crust
A
- 10-70km
- rich in silicates
- Aluminium minerals
2
Q
Oceanic crust
A
- thinner 5km
- denser
- comp similar to basalt
- Magnesium
- Silicate minerals
3
Q
Mantle
A
-thickest layer
- molten rock
- convection currents in upper mantle
- high temp & pressure
- mostly silicates
4
Q
Core
A
Composed mainly of iron, nickel, cobalt
5
Q
Outer core
A
- liquid
- Iron, Nickel, some lighter elements
- convection currents causing magnetic field.
6
Q
Inner core
A
- solid
- Mostly Fe with some Ni
7
Q
Types of evidence
A
- fit of continents
- distribution of ancient fossils
- similar rocks/mountain ranges
-location of ancient climatic zones(e.g. marks from glaciers)
8
Q
Evidence supporting theory of plate tectonics
A
- Seafloor ridges
- Paleomagnetism
- Location of volcanic activity and earthquakes
9
Q
Seafloor ridges
A
- Under sea volcanic mountain ranges
- Mid ocean ridges
- New seafloor formed
- Record of magnetic field locked
10
Q
paleomagnetism
A
- magnetic particles in molten rock align with magnetic field
- Pattern of reversed polarity repeats on either side of ridges and explain formation through seafloor ridges
11
Q
convection currents
A
-Liquid in constant motion
- Hot liquid rises up and cool goes down causing the plates to move
-in mantle and outer core
12
Q
Subduction
A
- Convergent boundaries
- Lighter plate floats on top and other goes below and melts causing volcanoes to form
13
Q
Divergent
A
- Plate boundary where two plates diverge going outwards
- Volcanoes
14
Q
Convergent
A
- Plate boundary where the plates go against each other
- Volcanoes and earthquakes
15
Q
Transform
A
- Rub against each other
- Earthquakes
- stored friction gives way to form earthquakes
16
Q
Hot spots
A
- Stationary plumes of magma in the earth’s crust that slip through to form volcanoes.
- Form islands
- Help to find out speed of movement of tectonic plates.
17
Q
Folding
A
- pressure exerted inwards from both ways
- Bend in layers of rock
18
Q
Anticlyne
A
- Upwards bend in folding
19
Q
Syncline
A
- Downwards bend in folding
20
Q
Faulting
A
- stresses overcome internal strengths of rock resulting in fracture
- Displacement of once connected blocks of rock along a fault plane
21
Q
Normal fault
A
- falls down
22
Q
Reverse fault
A
- slides up
23
Q
Strike-slip fault
A
- two blocks slide past each other
24
Q
Volcano location
A
- Normally at plate boundaries
- convergent or divergent
- except hot spots
25
Earthquake location
- Normally at plate boundaries
- normally at transform and convergent.
26
Seismogram
- a record of seismic waves from an earthquake
27
Seismograph
- measuring instrument that creates seismogram
28
P-waves
- solid and liquid
- faster
- longitudinal
29
S-waves
- slower
- solid
- transverse meaning at right angle to direction of travel
30
Surface waves
- travel just under earth's surface
- when source is close to the earth's surface
- slowest but most destructive
31
Love
- horizontal shearing of the ground
- slightly faster than Rayleigh
32
Rayleigh
- travel as ripples
- slowest
33
Composite volcano
- tall steep cones
- explosive volcanoes
34
Shield volcano
- very large gently sloped
- effusive (poured) volcanos
35
Active, dormant, & extinct volcanoes
- Active: erupting or recently erupted
- Dormant: not erupted for over 20 years
- have not erupted for thousands of years
36
Earthquake measurements
- measured using a seismograph
- released in seismic waves
- stronger the earthquake the higher the number on the Richter scale
