Star formation (and
associated planets)
from a nebula
The Earth’s Layers
Earth Interior
(some editions: TEXT p. 209)
“Above the core is the mantle,
containing molten rock, or
magma, that slowly circulates
in convection cells, much as
the atmosphere does”.
NOTE to clarify the description
of mantle: The mantle contains
magma in it’s upper region that
seeps into the crust and erupts
as lava. The mantle itself is a
SOLID that behaves as a viscous
liquid over geologic time.
Therefore, it is the solid mantle
that circulates in convection
cells, not the magma.
Interior Earth
Earth
Interior
(not
to scale)
Be able to locate:
inner core
outer core
upper mantle
lower mantle
continental crust
oceanic crust
(not to scale)
Moho
CMB
lithosphere
asthenosphere
boundaries that separate a change in composition
boundaries that separate a change in physical properties
In what region would you find:
“plates”
brittle material
highly plastic material
flowing liquid metal
large scale convection (heat transfer)
frictional coupling
Seismic Evidence of Earth’s Layers
• Earthquake- energy released by brittle substance
(lithosphere);Energy is in the form of waves that radiate
• Seismographs & Seismograms
– Surface- cause damage at the surface
– Body- travel through the Earth
5
• P- Primary; Arrive 1st; Compressional (Longitudinal in
physics)
• S- Secondary; Arrive 2nd; Shearing (Transverse in physics)
• All waves increase in velocity with increasing density; but
s waves can’t penetrate liquids or gasses
• Gap between p & s waves tell you how far away the EQ is
Seismograms
generated
by seismographs
6
Seismic Body Waves
(blue dot represents a solid particle in the path of the seismic wave)
http://www.classzone.com/books/earth_science/terc/content/visualizations/es1002/es1002page01.cfm?chapter_no=10
Evidence for Earth’s internal structure
is from seismic wave refraction (change in velocity) when traveling from one
density layer into a different density layer
Seismic waves through undifferentiated planet.
Seismic waves through differentiated Earth.
http://www.classzone.com/books/earth_science/terc/content/visualizations/es1009/es1009page01.cfm?chapter_no=10
APES
Earthquakes and Plates
Earthquakes and Plate Boundaries
The map below shows the type of data that helped geologists understand where and why most earthquakes occur. Study the globa l distribution and
depth of earthquakes (M > 4) that occurred between 1975 and 1999.
Based on the locations of quakes, try to outline the edges of the lithospheric plates and label each with its name.
Large plates: No. American, So. American, Eurasian, Indo-Australian, Antarctic, African, Pacific
Smaller plates: Nazca, Philippine, Cocos, Arabian, Juan de Fuca, Caribbean, Scotia
http://earthquake.usgs.gov/regional/neic/
Earth’s Lithospheric Plates
http://geomaps.wr.usgs.gov
Heat Transfer & Melting the Mantle
Convection  Plate Movement
Intraplate  Hot Spots
Continental + Continental Convergence
(Collision)
Himalayan Mts
Continental + Oceanic Crust
(Subduction)
Cascade Mts
Andes Mts
Oceanic + Oceanic Crust
(Subduction)
Indonesian Islands
Japanese
Islands
Dynamic Activity at Plate Boundaries
Divergence
Subduction (convergence)
Subduction leading to collision (convergence) and formation of Himalayas
Divergence: http://www.classzone.com/books/earth_science/terc/content/visualizations/es0903/es0903page01.cfm?chapter_no=09
Subduction: http://www.classzone.com/books/earth_science/terc/content/visualizations/es0902/es0902page01.cfm?chapter_no=09
Collision:
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0808/es0808page01.cfm?chapter_no=08
(some editions: TEXT p. 213)
“Because the subducted
plate will melt, rising magma
may be the source of new
volcano formation”.
NOTE to clarify formation
of subduction zone
magma: The subducted
slab dehydrates and
releases water to the
mantle, lowering the
mantle melting
temperature.
http://www.columbia.edu/~vjd1/subd_zone_basic.htm
Divergence
(Decompression)
•
•
•
•
•
Separation of 2 plates
“Seafloor spreading”
Mid-Ocean Ridges (MOR)
Forms new ocean crust
Mid-Atlantic Ridge which is
visible on land in Iceland
• Continental rifts (East Africa)
Transform Boundaries
•
•
•
•
Occurs at divergent boundaries
2 plates slide past each other
This sliding is not smooth. Plates lock
and build up tension.
Then the plates “snap” and release that
energy  earthquake!
http://www.youtube.com/watch?NR=1&v=ZxPTLmg0ZCw&feature=endscreen
Intraplate Dynamic Activity
•
•
•
•
•
Individual column of magma that rises
up and punches through the
lithosphere
Forms chains of volcanoes as a plate
moves over the hot spot
~100 Hot Spots
10% of heat transfer
Decompression melting (like
divergence)
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0904/es0904page01.cfm?chapter_no=09
Mantle plume Volcanism
Chains of
volcanoes formed
as a plate moves
over a hot spot
with rising
magma.
Diagram plate movement and hot spot activity on
the “Earths Interior” worksheet
Practice Worksheet
APES
EARTH SYSTEM and EARTH RESOURCES
GEOTHERMAL ENERGY
drives tectonics
creates topography
creates quake hazards and volcanic hazards
SOLAR ENERGY
drives wind flow and water cycle
flattens topography
creates soil resources and water resources
GEOTHERMAL and SOLAR ENERGY
together drive rock cycle
concentrate particular minerals and rocks
creates ore resources
Soil
Properties
Sediments that make up Soil
strongly affect soil permeability
(Some editions: textbook errors):
Figure 8.23 caption “Soil porosity” should be “Soil permeability”.
p.224: 2nd column, 1st full paragraph “The porosity of soil..” should be “permeability”.
p.224: 2nd column, last line “..porous..” should be “permeable”.
Sediments can be Sorted by Size
When transported by water or wind
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0604/es0604page01.cfm?chapter_no=06
Sediments that form Rocks
must be cemented together
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0605/es0605page01.cfm?chapter_no=06
Mining Methods
are determine by the resource location and formation