Prac Exam 2

Question 2

The remnant magnetic signature of rocks (paleomagnetism) is an important tool to understand continental drift and inform on past continent reconstructions. What does this remnant magnetic signature show over time for continental rocks and continents?

Question 3

What is the mantle wedge? (2 marks)

Which part of the mantle is it comprised of? (1 mark)

What is a metamorphic core complex? (2 marks)

Question 4

A number of geophysically defined boundaries exist as we descend from the surface to centre of the Earth.

a) What is the name of the boundary that defines the base of a tectonic plate? (2 marks)

b) What is an important property that defines this boundary? (1 mark)

c) Is the depth of this boundary from the Earth’s surface always the same across the globe? YES/NO (1 mark)

Question 5

In what tectonic setting (ie., contractional, transform, extensional, stable cratonic) would you most likely find such a complex forming? (1 mark)

Question 6

Which one of the following mountain ranges have been formed by continental collision at a convergent plate margin?

Great Dividing Range
New Zealand Alps
The Andes
The Himalayas
The Rocky Mountains

Question 7

Which of the following forces is prevalent at divergent plate margins?

Question 8

Which type of seismic activity is associated with convergent plate margins?

Shallow <70 km deep
Intermediate 70-300 km deep
Deep >300 km
Earthquakes from 0 to 700 km deep
Earthquakes from 10 to 440 km deep

Question 9

The upper mantle is molten/partially molten to account for mantle convection, magmatism and plate tectonic movement.

YES or NO

Question 10

Which one of the following mechanisms is now considered to be the most important in explaining the movement of plates?

Ridge push (from mid ocean ridges)
Mantle plumes
Slab pull
Mantle conduction
Gravity

Question 11

Which of the following is associated with or produced along transform boundaries

Granitic magmatism
Transpressional mountain ranges
Crustal exhumation
Andesitic volcanic activity
Mid ocean ridge
Oceanic trench

Question 12

Mid ocean ridges are sited above upward convecting mantle convection cells

Question 13

A passive continental margin is called passive because during continental break-up, rifting was caused by plate tectonic forces such that the underlying mantle played a “passive” role during break-up.

True
False

Question 14

Which one of the following statements does NOT apply to the lithosphere?

It comprises the crust and uppermost mantle

It is a rigid/brittle layer

It has an average thickness of 7 kilometres

It is thicker under mountain ranges

Question 15

What is the dominant ultramafic rock type that forms the upper mantle?

Harzburgite
Wherlite
Gabbro
Peridotite
Anorthosite
Eclogite

Question 16

A tectonic plate comprises

The continental crust.

Continental and/or oceanic crust.

The lithosphere and the topmost part of the asthenosphere.

The crust (either continental or oceanic) and its underlying mantle lithosphere.

Answer 16

The crust (either continental or oceanic) and its underlying mantle lithosphere.

Question 17

A dacite has a higher silica content than an andesite

True
False

Question 18

Exhumation describes surface uplift

True
False

Question 19

Melting of mantle material along convergent margins to make magmas that can erupt along volcanic arcs is by decompression

True
False

Question 20

The fastest moving tectonic plates have the most amount of subducted oceanic crust (slab) connected to them to create a large slab pull force.

True
False

Question 21

The mantle source region for mid ocean ridge basalts occurs at greater depth than oceanic island basalts because mid ocean ridges are typically 2-4 km below sea level.

True
False

Question 22

How are Large Igneous Provinces and hostpot volcanism explained by mantle plume theory?

Question 23

Explain how the supercontinent cycle can have an effect on apparent sea level rise or fall and the flooding of continents.

Question 24

Name two mantle source domains defined by radiogenic isotope compositions that are thought to originate from ancient subduction.

Question 25

How does the lithospheric mantle differ from the asthenospheric mantle?

Question 26

What is the mantle wedge? (2 marks)

Which part of the mantle is it comprised of? (1 mark)

Question 27

A number of geophysically defined boundaries exist as we descend from the surface to centre of the Earth.

a) What is the name of the boundary that defines the base of a tectonic plate? (2 marks)

b) What is an important property that defines this boundary? (1 mark)

c) Is the depth of this boundary from the Earth’s surface always the same across the globe? YES/NO (1 mark)