Geology: Earth's Interior (Third Exam)
Terms in this set (30)
Most of our knowledge of Earth's interior comes from the study of
density and elasticity
Velocity of seismic waves depends of the ________ ___ _________ of the intervening material
_____ waves (S waves) cannot travel through liquids.
In solids, P waves travel _____ than S waves.
When seismic waves pass from one material to another, the path of the wave is _________
crust, mantle, and core
What are the three principal compositional layers of the Earth?
Lithosphere (sphere of rock)
Earth's outermost layer, consisting of crust and uppermost mantle. Cool, rigid shell. Averages 100 km in thickness.
Asthenosphere (weak sphere)
Beneath the lithosphere, contained in the upper mantle to a depth of about 660 km. Small amounts of melting allows the lithoshpere to move independently from this layer.
Mesosphere (lower mantle)
Rigid layer of Earth's interior, between the depths of 660 km and 2900 km. Very hot rocks and capable of very gradual flow.
Layer of Earth's interior that is composed mostly of an iron-nickel allow. Liquid layer that is 2270 km thick, convective flow within generates Earth's magnetic field.
Sphere in Earth's interior with a radius of 1216 km, stronger than the outer core, behaves like a solid.
Moho (Mohorovicic discontinuity)
Discovered in 1909, separates crustal materials from underlying mantle, identified by a change in velocity of P waves, states that mantle rocks are high density peridotites, and crust is composed of lower density granite or basalt.
Moho is the boundary between the _____ and the ______
The __________-asthenosphere boundary occurs at a low velocity seismic zone. Represents a partial melting of rocks. Weak zone over which the lithosphere moves. Boundary is about 100 km
The ____-______ boundary was discovered in 1914. Causes a 35 degree wide belt that is named the P-wave shadow zone.
The fact that S waves do not travel through the core provides evidence for the existence of a ______ layer beneath the rocky mantle.
P waves passing through the inner core show increased velocity suggesting that the inner core is _____.
_________ crust has average rock density of about 2.7 g/cm^3, composistion comparable to the felsic igneous rock granodiorite.
_______ crust has a density of about 3.0 g/cm^3 and is composed mainly of the igneous rock basalt.
The ______ contains 82% of Earth's volume. A solid, rocky layer. Upper portion has the composition of the rock peridotite.
mesosphere and asthenosphere
The mantle has these two parts:
What layer of Earth's interior is larger than the planet Mars?
Earth's core has an average density of ___g/cm^3. Approaches 14 g/cm^3 at some parts.
Earth's core is mostly ____.
conducts electricity, mobile
The requirements for the core to produce Earth's magnetic field are met in that it is made of material that ________ _________, and it is ______.
______ core rotates faster than the Earth's surface, rotation is set off 10 degrees from the Earth's poles.
Earth's temperature gradually increases with an increase in depth at a rate known as the _________ _______.
Heat flow in the crust takes place in a process called _________, rates of heat flow vary and are highest at oceanic spreading centers.
Heat flow in the mantle is known as _________.
______ _________ provides the force that propels the rigid lithospheric plates across the globe.