Download Geology

Geology Concepts
Mr. Clark
BHS
Key Concepts
 Major geologic processes
 Earthquakes and volcanoes
 Minerals, rocks, and the rock cycle
 Plate Tectonics
Structure of the Earth
Features of the Crust and Upper
Mantle
External Earth Processes
Erosion
Mechanical weathering
Frost wedging
Chemical weathering
Biological weathering
Natural Hazards: Earthquakes
 Features
 Magnitude
 Aftershocks
 Primary effects
 Secondary effects
Expected Earthquake Damage
No damage expected
Minimal damage
Canada
Moderate damage
Severe damage
United States
Natural Hazards: Volcanic Eruptions
extinct
volcanoes
central
vent
magma
conduit
magma
reservoir
Solid
lithosphere
Upwelling
magma
Partially molten
asthenosphere
Minerals and Rocks
Mineral (diamond, quartz)
Rock Types
Igneous (granite, basalt)
Sedimentary (limestone, sandstone)
Metamorphic (marble, slate)
Transport
Erosion
Deposition
Shale, Sandstone,
Limestone
Rock
Cycle
Weathering
Igneous Rock
Granite, Pumice,
Basalt
Sedimentary Rock
Heat,
Pressure
Heat,
Metamorphic Rock
Pressure
Slate, Quartzite,
Marble
Magma
(Molten Rock)
Oceanic crust
(lithosphere)
Abyssal Oceanic
floor
ridge
Abyssal
floor
Abyssal plain
Abyssal
hills
Trench
Folded mountain belt
Craton
Volcanoes
Continental
shelf
Continental
slope
Continental crust
(lithosphere)
Mantle (lithosphere)
Mantle (asthenosphere)
Mantle
(lithosphere)
Continental
rise
Abyssal plain
Spreading
Oceanic tectonic
center
plate
Ocean trench
Oceanic tectonic
plate
Collision between
two continents
Plate movement
Tectonic plate
Plate movement
Oceanic
Subduction crust
zone
Oceanic
crust
Continental
crust
Continental
crust
Material cools
as it reaches
the outer
mantle
Mantle
convection
cell
Two plates move
towards each other.
One is subducted
back into the mantle
on falling convection
current.
Cold dense
material falls
back through
mantle
Hot material
rising
through
the mantle
Mantle
Hot outer
core
Inner
core
Reykjanes
Ridge
EURASIAN PLATE
JUAN DE
FUCA PLATE
NORTH
AMERICAN
PLATE
CHINA
SUBPLATE
Transform
PHILIPPINE
fault
PLATE
PACIFIC
COCOS
PLATE
MidPLATE
Indian
Transform
Ocean
fault
Ridge
East Pacific
Rise
INDIAN-AUSTRLIAN PLATE
Southeast Indian
Ocean Ridge
MidAtlantic
Ocean
Ridge
EURASIAN
PLATE
ANATOLIAN
PLATE
CARIBBEAN
PLATE
ARABIAN
PLATE
AFRICAN
PLATE
SOUTH
AMERICAN
PLATE
Carlsberg
Ridge
SOMALIAN
SUBPLATE
Transform
fault
Southwest Indian
Ocean Ridge
ANTARCTIC PLATE
Convergent
plate boundaries
Plate motion
at convergent
plate boundaries
Divergent ( ) and
transform fault (
boundaries
)
Plate motion
at divergent
plate boundaries
Animation
Plate margins interaction.
Click to view
animation.
Divergent Boundary
Lithosphere
Asthenosphere
Oceanic ridge at a divergent plate boundary
Convergent Boundary
Trench
Volcanic island arc
Rising
magma
Subduction
zone
Trench and volcanic island arc at a convergent
plate boundary
Lithosphere
Asthenosphere
Fracture zone
Transform
fault
Lithosphere
Asthenosphere
Transform fault connecting two divergent plate boundaries
Liquefaction of
recent sediments
causes buildings
to sink
Landslides may
occur on
hilly ground
Shock
waves
Epicenter
Focus
Two adjoining plates
move laterally along
the fault line
Earth movements
cause flooding in
low-lying areas
No damage expected
Canada
Minimal damage
Moderate damage
Severe damage
United States
extinct
volcanoes
central
vent
magma
conduit
magma
reservoir
Solid
lithosphere
Upwelling
magma
Partially molten
asthenosphere
Erosion
Transportation
Weathering
Deposition
Igneous Rock
Granite,
pumice,
basalt
Sedimentary Rock
Shale, sandstone,
limestone
Heat, pressure
Heat, pressure,
stress
Magma
(molten rock)
Melting
Metamorphic Rock
Slate, marble,
quartzite
Black smoker
White
smoker
Sulfide
deposit
Magma
Tube worms
White crab
White clam
Geologic Time Scale
Because fossils appeared in a predictable
order, one can use them as relative time
markers.
What’s more you can define time periods
based on certain fossils that were living at that
time.
This enabled geologists to construct the
Geologic Time Scale and name its periods
based on the fossil record.
Plate Tectonics
Divergent boundary
Convergent boundary
Subduction zone
Transform fault
Earth’s Major Tectonic Plates
Plate Tectonics
Plate Tectonics:
Fundamentals
• Evidence - plate tectonics unites many
disparate observations
• Sea-floor spreading - the oceans widening is
the mechanism that moves the continents
Plate Tectonics:
Fundamentals
• Plate margins - convergent, divergent,
transform
• Continental crust vs. oceanic crust
• The Earth’s interior: lithosphere, mantle,
core
http://imiloa.wcc.hawaii.edu/krupp/BIOL101/present/lcture18/img009.jpg
Continental Drift
Alfred Wegener
(1880-1930)
Wegener’s version
of continental drift
(1912)
Wegener was correct…
but he had no mechanism.
Plate Tectonics - 1960s
• New data:
– the age of the ocean floor
– magnetic stripes
Magnetic Stripes and Seafloor Spreading
Magnetic Stripes and Seafloor Spreading
Magnetic Stripes and Seafloor Spreading
Seafloor Spreading
How does
seafloor spreading
lead to continental
breakup?
http://www.ac.wwu.edu/~debari/406/figs/divergent.jpeg
Plate Margins
http://earth.geol.ksu.edu/sgao/g100/plots/1203_03_plate.jpg
Transform fault
plate boundaries
Continental vs. Oceanic Crust
Oceanic vs. Continental
Crust
 Age:
OC = <180 m.y.a.
CC = 2-3 b.y.a.
 Thickness:
OC = 5-7 kilometers thick
CC = 10-70 km
Oceanic vs. Continental
Crust
 Composition:
OC = basaltic
CC = granitic
 Density:
OC = 3.0 grams per cubic centimeter
CC = 2.7 gm/cc
The Earth’s Interior
We know the Earth is layered because of
seismic wave data!
The Earth’s interior
• Composition:
– Crust – mafic / felsic
– Mantle - ultramafic
The Earth’s interior: 2 bases for
layering
• Viscosity/Velocity:
– Lithosphere - rigid & non- flowable, 0-150km
– Asthenosphere - soft & flowable, 150-400 km
( “upper mantle”)
– Mantle
• - transition zone (400-670 km)
• - lower mantle (670-2900 km)
– Core
Mantle Convection: the mechanism
for plate tectonics?
Plate tectonics explains
things, for example...
• Mountain belts
• The Hawaiian islands