Class Notes- Unit 3 Flashcards
Where does evidence of the Earth’s interior come from?
- Astronomy
- Igneous Rocks
- Gravity
- Magnetism
- Seismology
- Heat Flow
- Experimental Petrology
What is Earth’s core composed of?
Fe and NI – metallic
Which is solid and which is liquid with Earth’s inner and outer core?
Inner: solid
Outer: liquid
What is the mantle composed of?
Fe, Mg, silicate
Is the mantle rocky and solid or molten and liquid?
rocky and solid
What do the asthenosphere and lithosphere compose?
mantle
How would one describe Earth’s crust?
complex – rocky
What is the Earth’s surface composed of?
- oceanic crust
2. continental crust (mountains, plain, and shields)
With plate tectonics, how is the Earth a “heat engine”?
The earth is a “heat engine”. It cools itself by conduction, radiation, and convection.
What is “iron catastrophe”?
Fe droplets sink and silicates rise (b/c lighter weight materials float up).
Is there any of Earth’s primitive crust left?
no
What is gravitational (planetary) differentiation?
Fe droplets sink and silicates rise. It is the process that formed Earth’s core, mantle, and primitive crust. Also known as the Iron Catastrophe.
What did the Iron catastrophe or gravitational differentiation require?
That the Earth be liquid – molten earth – for a long time.
What is the silicate mantle?
Minerals (chemical composition) made of silicon (Si) and oxygen (O) plus other elements.
How did the crust (as we know it today) form?
Not as a result of the iron catastrophe. It instead is the result of over 4 x 10^9 years of active geological processes – dynamic Earth.
When did the iron Catastrophe take place?
~ 4.54 Ga - 4.53 Ga
What is the distance from the sea level to the outer core?
2900 km
What is solidus?
the temp at which a liquid would melt or a liquid would freeze
What is the radius of the Earth?
6370 km
What are the two ways to discuss the outer part of the Earth?
- chemical composition (rock type)
2. physical strength
What is isostasy?
floating equilibrium between rock masses
What is the chemical composition of the continental crust?
granatic
What is the chemical composition of the oceanic crust?
basalt
What is the distance (in km) from the continents to the moho?
35 km
What is the distance from the ocean surface to the Moho?
8 km
On average, how deep are oceans (in km)?
~ 4 km
What is the depth of the continental crust?
2.7
What is the depth of the oceanic crust?
3.0
The lithosphere is___km under the sea floor?
100
What is the tempt of the asthenosphere?
1280 degrees C
The mantle to the moho is___km.
150
Mantle to lower mantle is___km.
600
By how many degrees C does the geothermal gradient drop per kilometre?
30 degrees C per kilometre
How many kilometres below the surface do volcanoes come from?
200 km
