Chapter 1: The Earth in Context Flashcards
What are volatile materials?
hydrogen, helium, methane, ammonia, water, and carbon dioxide
- remain in a gaseous state closer to the sun
- beyond the ‘frost line’ some volatiles can freeze into ice
What are refractory materials?
Solid soot sized particles of dust
- melt only at high temperatures
- planets closest to the sun are largely made up of refractory materials
What are planetesimals?
Large grainy blocks of rock in space whose diameter exceeded about 1km.
- Because of their mass, planetesimals exert enough gravitational attraction to pull in other objects that are nearby
- Eventually forms a protoplanet
Differentiation
When the heat in a planetesimal rises high enough to cause internal melting, dense metal (mostly iron) separated out and sank to the center of the planet body, whereas relatively lighter rocky materials remained in a shell surrounding the center.
Aka: How planets developed internal layering early in their history. (pg. 26)
Magnetosphere
The region inside Earth’s magnetic shield
Groundwater
Water filling tiny holes and cracks underground, down to a depth of several kilometers.
Hydrosphere
Oceans, surface water on land, and groundwater (pg. 32)
Geosphere
The solid earth from the surface to the center (pg. 33)
Topography
the variation in land surface elevation
Bathymetry
variations in the depth of the seafloor
Continental shelves
regions where water depths are generally less than 200m
internal energy
heat (thermal energy) stored or produced inside the Earth. (pg. 35)
external energy
reaches the Earth from outside of it (pg. 35)
- comes in the form of radiation from the sun
Chemical Layering (egg example)
- Core: iron rich (most dense)
- Mantle: peridotite
- Crust: basaltic or granitic (least dense)
(pg. 36)
Earthquake
When the Earth breaks along a fault; the sudden movement that generates vibrations, and the ground shaking that results when these vibrations reach the Earth’s surface.
Seismic waves
Earthquake waves
oceanic crust
thinner & more dense than continental crust
- younger
- the top layer is made up of sediment containing clay and tiny shells, basalt, and gabbro (deepest)
- ~7-10km thick
(pg. 38)
continental crust
Thicker and less dense than oceanic crust
- older
- ~25-70km thick
- Granitic felsic
the mantle
- Mostly s o l i d
- largest part of the earth in terms of volume
- made up entirely of ultramafic (dark and dense) rock called peridotite
- two layers, upper and lower mantle
transition zone
the part of the mantle where seismic-wave velocities increase in a series of steps due to abrupt changes in the character of minerals making up mantle rock.
the core
- made up of iron alloy (iron mixed with nickel and lesser amount of oxygen, silicon, and sulfur)
- outer core: liquid because the temperature in the outer core is so high that even the great pressures squeezing the region cannot keep the atoms locked into a solid framework, generates the Earth magnetic field
- inner core: solid
rigid materials
can bend or break but cannot flow easily
plastic materials
relatively soft and can flow without breaking
lithosphere
rigid outer layer of the Earth, made up of the crust plus the uppermost part of the upper mantle (lithospheric mantle)
NOTE: lithosphere and crust are NOT the same thing! The crust is the top layer of the lithosphere.
asthenosphere
- Below the lithosphere, the portion of the mantle that behaves like soft plastic and can flow.
Types of waves which reveal the materials/density of the earths interior?
s-waves, p-waves, and surface waves
P - Waves
- Horizontal particle motion
- Go through whole interior of the earth (solids and liquids)
- First seismic waves that move the seismometer
S - Waves
Does not travel through liquid
Surface Waves
most damaging to the earths surface
mechanical layering
Determined by physical properties of the layers; based on temperature mainly
○ Solid inner core
○ Liquid outer core
○ Mesosphere (solid)
○ Asthenosphere: Plastic (weak and deformable)
○ Lithosphere (Solid)
