Terms in this set (20)
What happens during the process of differentiation?
The separation of materials according to density. After a planet is formed, it gets melted by heat from several sources. The denser materials sink to the core and the lighter materials rise to the crust.
What three things heated the Earth shortly after formation?
1) Gravitational energy left over from the formation of the planet
2) Meteor bombardment, which was intense in the very early solar system
3) Decay of radioactive material trapped in the body of the Earth
What makes up the Earth's lithosphere?
The upper part of the mantle and the crust.
What produces seismic waves?
Earthquakes produce seismic waves.
What type of wave travels fastest?
Primary waves travel the fastest. They are also called P-waves.
What are the two cores?
Solid Inner Core and Liquid Outer Core
Of what are the cores made?
The cores are made of Iron and Nickel.
The liquid core produces the Earth's magnetic field.
What evidence proves plate tectonics?
1) The shapes of many continents are such that they look like they are separated pieces of a jigsaw puzzle. For example, look in the top right map of the previous page at the shape of the east coast of North and South America relative to the shape of the West coast of Africa and Europe.
2) Many fossil comparisons along the edges of continents that look like they fit together suggest species similarities that would make sense only if the two continents were joined at some point in the past. Likewise, there are geological formations that appear to end at the boundary of one continent and continue on the boundary of another continent.
3) A large amount of seismic, volcanic and geothermal activity is found along the conjectured plate boundaries.
4) Ridges such as the Mid-Atlantic Ridge appear to be regions where plates are separating and the seafloor is spreading. The ridges are produced by lava welling up from between the plates as they pull apart. Likewise, mountain ranges appear to have formed where one plate is subducted. For example, the Himalayan Mountains are still growing, pushed up by the motion of the Indian Subplate as it passes under the Eurasian plate.
5) Magnetic anomaly stripes are observed in seafloor spreading zones such as the Mid-Atlantic Ridge. These stripes correspond to reversals of the direction of magnetization for seafloor rocks. The stripe pattern results because the Earth periodically reverses the polarity of its magnetic field. As the seafloor spreads, the direction of the current magnetic field is fixed into the rocks as they solidify from upwelling magma. Therefore, the stripes are a direct indication of seafloor spreading. For many geologists, this explanation of the magnetic stripe anomalies was the clinching argument leading to an acceptance of the plate tectonic hypothesis.
What were the two super continents.
Laurasia and Gondwanaland
What layer of the earth does the lithosphere sit on?
What moves the plates?
Very slow convection currents flow in the plastic asthenosphere and perhaps deeper in the mantle. These currents provide horizontal forces on the plates of the lithosphere.
What are the 4 types of plate boundaries?
divergent boundaries, convergent boundaries, collisional boundaries, transform boundaries
What made the Himalayas?
The release of gases from a planet's interior.
Where did our water come from?
The impacts of icy planetisimals rich in volatile material such as water.
What produced the planet's oxygen?
The Earth's oxygen was manufactured primarily by cyanobacteria.
What is ozone?
A thin layer in the stratosphere that contains an enhanced abundance of a highly reactive molecule made of three oxygen atoms.
What does the ozone do?
It is primarily responsible for absorbing the ultraviolet radiation from the Sun.
What hits the Earth's magnetosphere?
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