Oceanography Week Two
1. How do we think the planets formed and why do we have rocky and gaseous
planets?: Formed through planetary accretion. Further away from the sun planets are cooler and rocky. Closer to
the sun they are warmer and gaseous.
2. How does the composition of the crust differ from the whole-earth compo-
sition?: Earth's crust is primarily made up of Oxygen and Silicon. This means that the lighter elements are on the
outside of the planet with heavier metals found closer to the core.
3. Compare and contrast the properties of the lithosphere and the asthenos-
phere.: Lithosphere: hard cool shell, broken into series of movable plates, brittle, low density, crust and upper
mantle
Asthenosphere: soft hot plastic material in lower mantle, more dense
4. What are the three types of plate boundaries and what occurs at each?: Divergent
(spreading centers): plates move apart, recycling of material, new crust, shallow earthquakes
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, Convergent (subductions): plates move toward each other, crust destroyed, deep earthquakes
Transform (fault): plates slide in opposing directions, lithosphere breaks
5. How does earthquake focus change at subduction zones?: Earthquakes follow the
subduction zones of the crust that is being pushed deeper into the mantle creating earthquakes at various depths.
Earthquakes can't happen when mantel gets too plasticized (closer to core).
6. How old are the oldest ocean rocks - why so young?: The oldest ocean rocks are about 3
billion years old. Relatively young because of the recycling of material that happens at the divergent tectonic plates.
7. What is the Curie Point and why is it important regarding paleomagnetism?-
: Rocks lock in the magnetic field when lava flows cool. The Curie Point is the temperature at which certain materials
lose their permanent magnetic properties (lock in temp). This is important regarding paleomagnetism (the study of the
record of the Earth's magnetic field in rocks, sediment, or archeological materials) because the Curie Point is recorded
in the rocks and we can look at it to see layers of crust as it forms from the spreading center.
8. What's the significance of magnetic stripes - what do they tell us?: Tells us rate and
what sediments the new lithosphere is being created out of.
9. How is plate tectonics related to the rock cycle?: Rock formations are usually the direct result
of plate convergences. At diverging plate boundaries, convection currents bring hot magma to the surface. This hot
magma flows out onto the ocean floor, forming extrusive, finely grained igneous rocks. At convergent plate boundaries,
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1. How do we think the planets formed and why do we have rocky and gaseous
planets?: Formed through planetary accretion. Further away from the sun planets are cooler and rocky. Closer to
the sun they are warmer and gaseous.
2. How does the composition of the crust differ from the whole-earth compo-
sition?: Earth's crust is primarily made up of Oxygen and Silicon. This means that the lighter elements are on the
outside of the planet with heavier metals found closer to the core.
3. Compare and contrast the properties of the lithosphere and the asthenos-
phere.: Lithosphere: hard cool shell, broken into series of movable plates, brittle, low density, crust and upper
mantle
Asthenosphere: soft hot plastic material in lower mantle, more dense
4. What are the three types of plate boundaries and what occurs at each?: Divergent
(spreading centers): plates move apart, recycling of material, new crust, shallow earthquakes
1/3
, Convergent (subductions): plates move toward each other, crust destroyed, deep earthquakes
Transform (fault): plates slide in opposing directions, lithosphere breaks
5. How does earthquake focus change at subduction zones?: Earthquakes follow the
subduction zones of the crust that is being pushed deeper into the mantle creating earthquakes at various depths.
Earthquakes can't happen when mantel gets too plasticized (closer to core).
6. How old are the oldest ocean rocks - why so young?: The oldest ocean rocks are about 3
billion years old. Relatively young because of the recycling of material that happens at the divergent tectonic plates.
7. What is the Curie Point and why is it important regarding paleomagnetism?-
: Rocks lock in the magnetic field when lava flows cool. The Curie Point is the temperature at which certain materials
lose their permanent magnetic properties (lock in temp). This is important regarding paleomagnetism (the study of the
record of the Earth's magnetic field in rocks, sediment, or archeological materials) because the Curie Point is recorded
in the rocks and we can look at it to see layers of crust as it forms from the spreading center.
8. What's the significance of magnetic stripes - what do they tell us?: Tells us rate and
what sediments the new lithosphere is being created out of.
9. How is plate tectonics related to the rock cycle?: Rock formations are usually the direct result
of plate convergences. At diverging plate boundaries, convection currents bring hot magma to the surface. This hot
magma flows out onto the ocean floor, forming extrusive, finely grained igneous rocks. At convergent plate boundaries,
2/3
