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Flashcards in Interior Processes Deck (33)
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1

What is an anticline?

An upfold in rock layers

2

What is a syncline?

A downfold in rock layers

3

How do dome mountains form?

Rock layers get pushed up and dome is formed

4

Describe a Plutonic Dome mountain and age of layers

Igneous intrusion pushes up rock layers and sedimentary layers wear away leaving igneous rocks at top.
Top layer is younger

5

Describe a Tectonic Dome mountain and age of layers

Uplifting force pushes up rock layer
Top layer is older

6

What are plate tectonics?

A theory that the surface of the Earth is in giant pieces or lithospheric plates and the movement, interactions and formation of these plates

7

What is the Elastic Rebound Theory?

Friction prevents 2 plates from moving, strain becomes too great and plates suddenly move. Cause of Earthquake

8

What is a shadow zone and what does it indicate?

Area with no p-waves or s-waves from an Earthquake. Occurs because p-waves get refracted and s-waves can't transmit through liquid.
Indicates that outer core is liquid because outer core is up to 2900km below surface and peed of p-waves increase at 5200km
Also that the inner core must be solid

9

What is a fault?

Breaks in lithosphere where movement has occurred. Have footwalls and hanging walls

10

Describe the 3 major types of faults

Normal: Hanging wall slides down as tension pulls crust apart
Reverse: Hanging wall slides up as compression occurs
Strike-Slip: Hanging wall moves horizontally as it slides past footwall (San Andreas fault)

11

What are folds?

Occur deep below surface, sometimes exposed due to uplift, weathering and erosion. Main types are anticline and syncline

12

How does magma form at subduction boundaries?

Water in the subducted rock is released into the athensophere, then the water lowers melting temperatures of materials in the athensophere, leading to the formation of magma.

13

What is Liquefaction?

Process where sediment/soil acts like a liquid causing buildings to sink

14

What are the three types of magma and explain their characteristics. (I.e Content and where they are found)

Basaltic: 50% silica, low gas, low viscosity, high melting temp, rarely explosive. Found in rift and hot spots
Andesitic: 60% silica, medium gas, medium viscosity, medium melting temp, sometimes explosive. Found in subduction boundariess
Rhyolitic: 70% silica, high gas, high viscosity, low melting temp, usually explosive. Found in continental hot spots

15

Explain Earthquake body waves and the two types

Body Waves: Waves of energy which travel from focus of an earthquake.
P-waves (Primary Waves):
Compression a.k.a longitudinal waves
Vibrate parallel to direction in which the wave is travelling
S-Waves (Secondary Waves):
Shear waves a.k.a Transverse waves
Vibrate perpendicular to direction that the wave is travelling

16

What are the differences and similarities between p-waves and s-waves

P-waves travel 2x faster than s-waves
Both travel faster in denser materials

17

Explain Earthquake surface waves and the two types and which travels faster

Surface Waves: Waves that travel along the surface of Earth
Love Waves: Side - side movement a.k.a surface transverse waves
Rayleigh Waves: Travel in elliptical patterns a.k.a torsional vibrations
Love waves travel faster than Rayleigh waves

18

Describe the Divergent plate boundary

Plates diverge (move away) from each other
Usually along ocean floors and produce rift valleys
Rift valleys have fracture zones which are perpendicular to ridge
Earthquakes occur at fracture zones

19

Describe the Convergent plate boundary

Plates converge (move towards) each other. 2 types
Subduction: One plate goes under the other
Collision: Plates hit each other head on

20

Describe the Transform plate boundary

Plates slide by each other. Ex: San andreas fault

21

What is a Richter scale?

Used to express strength/magnitude of Earthquake

22

What contributes to continental growth?

Deep-sea Sediments: Scraped off sediments as oceanic plate submerges under continental
Igneous Rock: From cooled magma builds up surface of continents
Sediments: Deposited by rivers, helps build up edges
Terrane: Large piece of litho. plate displaced over a large area

23

Describe the 3 chars. of a Terraine

Must be bound on all 3 sides by faults
Fossils must be completely different than neighbouring fossils in area
Different magnetic record, compared to that around it

24

What is the Mohorovicic Discontinuity?

Change in velocity of p-waves and s-waves at boundary between crust and mantle

25

What is the Transition Zone?

At depths between 400 and 670 km, seismic wave velocity significantly increase. Located in middle of the mante

26

Explain Wegner's continental drift hypothesis and it's strengths and weaknesses

The theory that overtime continents drift from one location to another

27

What were the proofs to Wegner's continental drift hypothesis?

Coastlines seem to fit
Fossil remains of mesosaurus were only found near the east coaast of S.A and west coast of Africa
Unique rock formation on S.A and Africa which match up
Climate change evidence consistent with Africa and S.A

28

What were the disadvantages to Wegner's continental drift hypothesis?

Does not explain how continents move
Suggested plates move 100 times the speed of what they actually move

29

What are the 3 causes of plate movement?
(Very long answer)

Mantle Convection: Heat transfer process which heat from core goes through mantle. Convection cells form in the middle
Slab Pull: Force at subduction boundary. Subducting part of litho. plate exerts pull on rest of plate
Ridge Push: At ridges hot magma rises and heats rocks near it and the rocks expand and become elevated above sea-floor. This produces downward slope away from ridge and older rocks cool, become denser and slide down slope. The rising magma forms new rocks at M.O.R and denser litho, slides away

30

What is stress and explain the 3 main types

Stress: Internal resistance of an object to a force that strains that particular body
Compression: Rock layers are squeezed inwards and layers become thicker and shorter
Tension: Rock layers are stretched outwards and layers become thinner and longer (Thinner layers are weaker and can fracture)
Shear: Rock layers slide past each other. Can change shapes of rocks