Earth Flashcards
What is Albedo?
Amount of sunlight reflected back into space
Earth’s albedo = 31%
What is Seismic Waves?
Vibrational waves generated by earthquakes. Travel from the origin along the surface and through the interior of the Earth
Why does the Earth have an iron core?
Chemical Differentiation:
Dense iron sank to center forming core
Less dense rock rose to surface
Earth formed solid crust as it cooled
How does the Earth have magnetic field?
The Earth’s rapid rotation causes molten metals in
the outer core to flow generating a magnetic field
What are the Van Allen belts?
two regions of intense radiation partly surrounding the earth at heights of several thousand kilometers.
What are Igneous rocks?
It is formed from the cooling and solidification of molten rock
Extrusive: surface, lava; eg: basalt
Intrusive: under the surface, magma; eg: granite
What are Sedimentary rocks?
Made from the accumulation and gradual compression of sediments
Eg: Sandstone; Limestone
What are Metamorphic rocks?
Rocks transformed into new forms under high
temperatures and pressures beneath the surface of the Earth
Eg: Marble, Gneiss
How old is the Earth?
4.5 billion years
How many plate tectonics are there on Earth?
Seven major plates along a number of smaller minor plates
What is the Asthenopshere
A layer of thick, viscous rock under the lithosphere that flows like a liquid
The plates float on this
What drives the plate motion?
Plate motion is driven by convection currents in the Earth’s mantle. In another word, heat
What are the crust types?
Oceanic: relatively dense, young seafloor crust
Continental: older, less dense
What are the three type of plate boundaries?
Convergent, Divergent and Transform
Describe Oceanic-Continental Convergence
Subduction
Eg: the Andes Mountains
Moutains building, volcanoes, earthquakes
Oceanic-Oceanic Divergence
Seafloor Spreading
eg: the mid-atlantic ridge
Continental-Continental Convergence
Eg: India collided with Asia, forming Himalaya
Continental-Continental Divergence
Creating rift valley
Eg: The East African rift zone: Red Sea
Oceanic-Oceanic Divergence
Creating trench
Eg: The Mariana Trench
Explain Transform Boundaries
Plates slide past each other
Eg: The San Andres Fault
What are the two types of volcanoes?
Stratovolcanos: Found at tectonic plate boundaries, eg: Mt Fuji
Hot Spot Volcanism: A rising plume of magma within the Earth’s mantle results in the formation of a hotspot beneath the crust producing volcanoes, SHIELD volcano: formed under hotspot eg: Hawaii, Yellow Stone
What are the two types of tides on Earth?
Spring tides: new and fool moon
Neap tides: quarter moons
What are the other tidal effects?
Slowers Earth’s motions
make the moon moves further away from Earth
