Shared Flashcard Set

Details

Test #3
Earth's Interior
25
Geology
Undergraduate 1
04/01/2014

Additional Geology Flashcards

 


 

Cards

Term
What we know about the Earth’s Interior
Definition
comes from the study of seismic waves that
travel through the Earth
Term
How Earthquakes (Seismic Waves) Reveal the Inside of the Earth
Definition
1. Velocity
2. Reflection and Refraction
3. Type of Wave
Term
Velocity of Seismic Waves
Definition
velocities of seismic waves increase when traveling through denser materials.
Term
Density differences may be due to:
Definition
1.different compositions
2.changes in pressure and temperature
3.changes in physical state (solid vs. liquid)
Term
Reflection
Definition
return of waves toward surface after encountering a boundary
Term
Refraction
Definition
the bending / change in direction of a wave when it passes from one medium into another
Term
Types of Waves
Definition
1.P-waves transmitted through solids and liquids.
2.S-waves transmitted only through solids
Term
Earth's Layers
Definition
1. Crust
2. Mantle
3. Core
Term
Earth's Crust
Definition
1.composed mostly of silicate rich igneous rocks.
2.Density increases with depth.
Term
Layers of the Crust
Definition
1.Oceanic crust
2.Continental crust
3.Moho
Term
Oceanic Crust
Definition
1.mostly basaltic rocks (slightly denser than continental crust)
2.thin
3.forms at mid-ocean ridges (divergent plate boundaries)
Term
Continental Crust
Definition
1.composition varies (less dense than oceanic crust)
2.thick
Term
Moho
Definition
boundary between crust and mantle
Term
Lithosphere
Definition
crust and uppermost mantle
Term
Earth's Mantle
Definition
1.solid, composed of dense iron and magnesium silicate minerals.
2.Accounts for >82% of Earth’s volume
3.Layers of differing densities occur in the mantle as increasing pressure causes mineral structures to become more compact
Term
Layers of the Mantle
Definition
1. Upper Mantle(100 km-660 km)
2. Lower Mantle(660km–core: 2900 km)
3. "D" Layer
Term
Upper Level
Definition
1.Mantle lithosphere (moho–100 km)
2.Asthenosphere(100-410 km)–low velocity zone
3.Transition Zone (410-660)
Term
"D" Layer
Definition
1.bottom few hundred km
2.large horizontal variations in temperature and density
3.boundary with core is very uneven
Term
Earth's Core
Definition
composed of dense metals (mostly iron and nickel)
Term
Layers of the Core
Definition
1.Liquid outer core–S waves extinguished
2.solid inner core
3.Earth’s magnetic field is generated by circulation of the outer core
Term
Why is Earth Hot?
Definition
1.heat left over from collisions during planetary accretion
2.heat due to decay of radioactive isotopes
3.heat increases with depth (geothermal gradient)
Term
Heat Flow
Definition
Conduction and Convection
Term
Conduction
Definition
flow of heat through a material; only manner of heat transfer between Earth layers
Term
Convection
Definition
transfer of heat by circulation of material; cold sinks-hot rises
Term
Where does convection occur?
Definition
1. in outer core (liquid)
2. in mantle (even though solid)
Supporting users have an ad free experience!