EOS 170 Practice questions for midterm 1
1. How is it that the compositions of certain types of meteorite represent the bulk composition of planet
Earth? Approximately what age are these
meteorites: meteorites, like chondrites, make up a significant amount of the earths composition. they are remants of the
early solar system, dating to about 4.55 billion years old
2. How fast could a coronal mass ejection reach earth?: a few hours up to a day
3. What are the major rheological layers of the earth?: Lithosphere: Asthenosphere:
Mesosphere:
Outer Core:
Inner Core:
4. What is the chemical composition of the lithosphere?: the lithosphere is made up of oceanic and continental crust
Oceanic is mafic so therefore rich in silica, iron, and magnesium. Whereas continental is felsic so therefore is mostly
silica rich
5. What is the chemical composition of the asthenosphere?: The asthenos- phere is primarily composed of iron (Fe)
and magnesium (Mg) and silicate minerals
6. What is the chemical composition of the mesosphere?: The mesosphere (lower mantle) is composed mainly of
magnesium- and iron-rich silicate minerals
7. What is the chemical composition of the outer and inner core?: both com- posed mostly of liquid iron and nickel
but the inner is solid whereas the outer is liquid
8. Explain the basic rheology of the lithosphere: The lithosphere has a solid, brittle, capable of elastic
deformation and fracturing.
9. Explain the basic rheology of the asthenosphere: ductile and plastic allowing it to flow slowly over time under
pressure.
10.Explain the basic rheology of the mesosphere: solid, with high viscosity and the ability to deform slowly under
pressure.
11.Explain the basic rheology of the outer core: liquid, composed primarily of molten iron and nickel, allowing it
to flow and convect.
12.Explain the basic rheology of the inner core: solid, composed mainly of iron and nickel, and remains solid due to
the immense pressure at that depth
13.What are the Earth's main compositional layers? For each layer, is there a subtype?: Crust (oceanic,
continental)
Mantle
Core (inner, outer)
14.Explain the crust and state the basic chemical composition: Made up of continental and oceanic crust
, EOS 170 Practice questions for midterm 1
The continental crust is rich in felsic materials, while the oceanic crust is mostly comprised of basaltic materials
15.Explain the mantle and state the basic chemical composition: The mostly solid bulk of Earth's interior and is
composed of denser silicate minerals rich in magnesium and iron, making up about 67% of Earth's mass.
16.Explain the core and state the basic chemical composition: Mostly com- posed of iron and nickel, the core is
divided into a liquid outer core and a solid inner core
17.Describe the major differences between oceanic crust and continental crust in terms of their
composition and physical properties: Oceanic
- lighter
- primarily composed of basalt
- rich in magnesium, iron, and mafic minerals
- thinner (avg: 5-10km)
- younger (avg <200 myo)
Continental:
- denser
- primarily composed of granite
- rich in silicon, oxygen, and felsic minerals
- thicker (avg: 30-40km)
- older (avg: ~4 byo)
18.how do the differences between oceanic and continental crust explain the contrast in deformation observed
at ocean-continent convergent plate boundaries (subduction zones), versus continent-continent convergent plate
boundaries (continental collisions): subduction zones involving oceanic crust being subducted under the continental
crust due to its higher density
continental collisions lead to crustal thickening and mountain-building since neither continent can subduct.
19.What are coronal mass ejections, and how do they cause geomagnetic storms? Describe a few of the human
impacts of these events: basically a large EMP and cause geomagnetic storms by distorting the planets magnetosphere
causing destruction to any electronic equipment
20.How does the creation of new volcanoes and mountains provide evidence for the theory of plate tectonics:
Those both of those to be made, tectonic process need to occur such as sea floor spreading (divergent oceanic plate
boundary) or the creation of mountain ranges (convergent continental boundaries)
, EOS 170 Practice questions for midterm 1
21.Explain how fossil distribution provides evidence for continental drift: the same fossils found on different
continents suggest that they used to be one single continent that split up
22.Explain how the idea of "continental fit" provides evidence for continental drift: certain continents fit nicely
into each other such as the east coast of South America and southwest coast of Africa
23.Explain how seafloor magnetic stripping provide evidence for the theory of plate tectonics: When sea floors
spread they create new rock which contains pieces of magnetic material, these magnetic materials become polarized
due to earths magnetic field basically time stamping their creation
24.Which bathymetric features (bathymetry = sea floor topography), mapped using sonar initially during the
Second World War, were later used in the devel- opment of the theory of Plate Tectonics: mid-ocean ridges, deep-
sea trenches, and transform faults.
These features helped reveal the ocean floor's topography and the tectonic process- es at work beneath the surface.
25.What are the three basic types of fault and how they typically differ?: Nor- mal
Thrust Strike-
slip
These fault types differ primarily in the direction of movement and the stress conditions that create them
26.Explain what a normal fault is. How does it form, where is it usually associated with, and its dip angle:
Occurs due to horizontal extension when one block of crust (the hanging wall) moves down relative to the other block
(the footwall with a steep dip angle)
27.Explain what a Thrust fault is. How does it form, where is it usually as- sociated with, and its dip angle:
Forms under horizontal compression where the hanging wall is pushed up over the footwall (with a moderate dip angle)
28.Explain what a Strike-slip fault is. How does it form, where is it usually associated with, and its dip angle:
They are characterized by lateral movement, where two blocks slide past one another horizontally, high dip angle - 90)
29.Which type of fault is responsible for the largest (Mw>8) great earthquakes and what tectonic setting are
they associated with?: Thrust faults and are associated with subduction zones
1. How is it that the compositions of certain types of meteorite represent the bulk composition of planet
Earth? Approximately what age are these
meteorites: meteorites, like chondrites, make up a significant amount of the earths composition. they are remants of the
early solar system, dating to about 4.55 billion years old
2. How fast could a coronal mass ejection reach earth?: a few hours up to a day
3. What are the major rheological layers of the earth?: Lithosphere: Asthenosphere:
Mesosphere:
Outer Core:
Inner Core:
4. What is the chemical composition of the lithosphere?: the lithosphere is made up of oceanic and continental crust
Oceanic is mafic so therefore rich in silica, iron, and magnesium. Whereas continental is felsic so therefore is mostly
silica rich
5. What is the chemical composition of the asthenosphere?: The asthenos- phere is primarily composed of iron (Fe)
and magnesium (Mg) and silicate minerals
6. What is the chemical composition of the mesosphere?: The mesosphere (lower mantle) is composed mainly of
magnesium- and iron-rich silicate minerals
7. What is the chemical composition of the outer and inner core?: both com- posed mostly of liquid iron and nickel
but the inner is solid whereas the outer is liquid
8. Explain the basic rheology of the lithosphere: The lithosphere has a solid, brittle, capable of elastic
deformation and fracturing.
9. Explain the basic rheology of the asthenosphere: ductile and plastic allowing it to flow slowly over time under
pressure.
10.Explain the basic rheology of the mesosphere: solid, with high viscosity and the ability to deform slowly under
pressure.
11.Explain the basic rheology of the outer core: liquid, composed primarily of molten iron and nickel, allowing it
to flow and convect.
12.Explain the basic rheology of the inner core: solid, composed mainly of iron and nickel, and remains solid due to
the immense pressure at that depth
13.What are the Earth's main compositional layers? For each layer, is there a subtype?: Crust (oceanic,
continental)
Mantle
Core (inner, outer)
14.Explain the crust and state the basic chemical composition: Made up of continental and oceanic crust
, EOS 170 Practice questions for midterm 1
The continental crust is rich in felsic materials, while the oceanic crust is mostly comprised of basaltic materials
15.Explain the mantle and state the basic chemical composition: The mostly solid bulk of Earth's interior and is
composed of denser silicate minerals rich in magnesium and iron, making up about 67% of Earth's mass.
16.Explain the core and state the basic chemical composition: Mostly com- posed of iron and nickel, the core is
divided into a liquid outer core and a solid inner core
17.Describe the major differences between oceanic crust and continental crust in terms of their
composition and physical properties: Oceanic
- lighter
- primarily composed of basalt
- rich in magnesium, iron, and mafic minerals
- thinner (avg: 5-10km)
- younger (avg <200 myo)
Continental:
- denser
- primarily composed of granite
- rich in silicon, oxygen, and felsic minerals
- thicker (avg: 30-40km)
- older (avg: ~4 byo)
18.how do the differences between oceanic and continental crust explain the contrast in deformation observed
at ocean-continent convergent plate boundaries (subduction zones), versus continent-continent convergent plate
boundaries (continental collisions): subduction zones involving oceanic crust being subducted under the continental
crust due to its higher density
continental collisions lead to crustal thickening and mountain-building since neither continent can subduct.
19.What are coronal mass ejections, and how do they cause geomagnetic storms? Describe a few of the human
impacts of these events: basically a large EMP and cause geomagnetic storms by distorting the planets magnetosphere
causing destruction to any electronic equipment
20.How does the creation of new volcanoes and mountains provide evidence for the theory of plate tectonics:
Those both of those to be made, tectonic process need to occur such as sea floor spreading (divergent oceanic plate
boundary) or the creation of mountain ranges (convergent continental boundaries)
, EOS 170 Practice questions for midterm 1
21.Explain how fossil distribution provides evidence for continental drift: the same fossils found on different
continents suggest that they used to be one single continent that split up
22.Explain how the idea of "continental fit" provides evidence for continental drift: certain continents fit nicely
into each other such as the east coast of South America and southwest coast of Africa
23.Explain how seafloor magnetic stripping provide evidence for the theory of plate tectonics: When sea floors
spread they create new rock which contains pieces of magnetic material, these magnetic materials become polarized
due to earths magnetic field basically time stamping their creation
24.Which bathymetric features (bathymetry = sea floor topography), mapped using sonar initially during the
Second World War, were later used in the devel- opment of the theory of Plate Tectonics: mid-ocean ridges, deep-
sea trenches, and transform faults.
These features helped reveal the ocean floor's topography and the tectonic process- es at work beneath the surface.
25.What are the three basic types of fault and how they typically differ?: Nor- mal
Thrust Strike-
slip
These fault types differ primarily in the direction of movement and the stress conditions that create them
26.Explain what a normal fault is. How does it form, where is it usually associated with, and its dip angle:
Occurs due to horizontal extension when one block of crust (the hanging wall) moves down relative to the other block
(the footwall with a steep dip angle)
27.Explain what a Thrust fault is. How does it form, where is it usually as- sociated with, and its dip angle:
Forms under horizontal compression where the hanging wall is pushed up over the footwall (with a moderate dip angle)
28.Explain what a Strike-slip fault is. How does it form, where is it usually associated with, and its dip angle:
They are characterized by lateral movement, where two blocks slide past one another horizontally, high dip angle - 90)
29.Which type of fault is responsible for the largest (Mw>8) great earthquakes and what tectonic setting are
they associated with?: Thrust faults and are associated with subduction zones
