Transcript Tectonic plates - Hobbs High School

Third Rock From the Sun Notes
Plate Tectonics
Chapter Overview Questions
What major geologic processes occur within
the earth and on its surface?
 What are nonrenewable mineral resources
and where are they found?
 What are rocks, and how are they recycled
by the rock cycle?
 How do we find and extract mineral
resources from the earth’s crust, and what
harmful environmental effects result from
removing and using these minerals?

Chapter Overview Questions
Will there be enough nonrenewable mineral
resources for future generations?
 Can we find substitutes for scarce
nonrenewable mineral resources?
 How can we shift to more sustainable use of
nonrenewable mineral resources?

Chapter Overview Questions
What are the advantages and disadvantages
of conventional oil and nonconventional
heavy oils?
 What are the advantages and disadvantages
of natural gas?
 What are the advantages and disadvantages
of coal and the conversion of coal to
gaseous and liquid fuels?

Chapter Overview Questions

What are the advantages and disadvantages
of conventional nuclear fission, breeder
nuclear fission, and nuclear fusion?
Chapter Overview Questions
How can we improve energy efficiency and
what are the advantages of doing so?
 What are the advantages and disadvantages
of using solar energy to heat buildings and
water and to produce electricity?
 What are the advantages and disadvantages
of using flowing water to produce
electricity?
 What are the advantages and disadvantages
of using wind to produce electricity?

Chapter Overview Questions
What are the advantages and disadvantages
of burning plant material (biomass) to heat
buildings and water, produce electricity, and
propel vehicles?
 What are the advantages and disadvantages
of extracting heat from the earth’s interior
(geothermal energy) and using it to heat
buildings and water, and produce
electricity?

Chapter Overview Questions
What are the advantages and disadvantages
of producing hydrogen gas and using it in
fuel cells to produce electricity, heat
buildings and water, and propel vehicles?
 How can we make a transition to a more
sustainable energy future?

Description

Plate tectonics is the theory
explaining the movement of the
plates and the processes that occur
at their boundaries.
GEOLOGIC PROCESSES
The earth is made up of a core, mantle, and crust
and is constantly changing as a result of processes
taking place on and below its surface.
 The earth’s interior consists of:

Core: innermost zone with solid inner core and molten
outer core that is extremely hot.
 Mantle: solid rock with a rigid outer part
(asthenosphere) that is melted pliable rock.
 Crust: Outermost zone which underlies the continents.

Volcanoes
Abyssal hills
Oceanic crust
(lithosphere)
Abyssal Oceanic
floor
ridge
Abyssal
floor
Trench
Folded
mountain
belt
Abyssal plain
Craton
Continental
shelf
Continental
slope
Continental
rise
Continental crust (lithosphere)
Mantle (lithosphere)
Fig. 15-2, p. 336
Spreading
center
Collision between
two continents
Subduction
zone
Continental
crust
Oceanic
crust
Ocean
trench
Oceanic
crust
Continental
crust
Material cools Cold dense
as it reaches material falls
the outer back through
mantle
mantle
Hot
Mantle
material
convection
rising
cell
through
the
mantle
Two plates move
towards each other.
One is subducted
back into the mantle
on a falling convection
current.
Mantle
Hot outer
core Inner
core
Fig. 15-3, p. 337
GEOLOGIC PROCESSES

Huge volumes of heated and molten rack
moving around the earth’s interior form
massive solid plates that move extremely
slowly across the earth’s surface.

Tectonic plates: huge rigid plates that are
moved with convection cells or currents by
floating on magma or molten rock.
The Earth’s Major Tectonic
Plates

The extremely slow movements of these
plates cause them to grind into one another
at convergent plate boundaries, move apart
at divergent plate boundaries and slide past
at transform plate boundaries.
Figure 15-4
Fig. 15-4, p. 338
JUAN DE
FUCA PLATE
EURASIAN PLATE
NORTH
AMERICAN
PLATE
ANATOLIAN
PLATE
CARIBBEAN
PLATE
ARABIAN
AFRICAN PLATE
PLATE
PACIFIC
PLATE
SOUTH
AMERICAN
NAZCA PLATE
PLATE
SOMALIAN
SUBPLATE
CHINA
SUBPLATE
PHILIPPINE
PLATE
INDIAAUSTRALIAN
PLATE
ANTARCTIC PLATE
Divergent plate
boundaries
Convergent plate
boundaries
Transform
faults
Fig. 15-4a, p. 338
Trench
Volcanic island arc
Craton
Transform
fault
Lithosphere
Asthenosphere
Divergent plate boundaries
Lithosphere
Rising
magma
Asthenosphere
Convergent plate boundaries
Lithosphere
Asthenosphere
Transform faults
Fig. 15-4b, p. 338
Pacific Plate



The Pacific plate is off the coast of
California. Lots of volcanoes and
earthquakes occur here.
“California will fall into the ocean” idea.
It is the largest plate and the location of
the ring of fire.
Boundaries

Divergent – the plates move apart
in opposite directions.
– the plates push
together by internal forces. At most
convergent plate boundaries, the
oceanic lithosphere is carried
downward under the island or
continent. Earthquakes are common
here. It also forms an ocean ridge or
a mountain range.
Convergent
Boundaries (Continued)


Transform – plates
slide next or past
each other in
opposite directions
along a fracture.
California will not
fall into the ocean!
GEOLOGIC PROCESSES

The San
Andreas Fault
is an example
of a transform
fault.
Figure 15-5
Importance

Plate movement adds new land at
boundaries, produces mountains,
trenches, earthquakes and
volcanoes.
The Rock Cycle – the interaction
of processes that change rocks
from one type to another
Rock Cycle
Figure 15-8
Erosion
Transportation
Weathering
Deposition
Igneous rock
Granite,
pumice,
basalt
Sedimentary
rock
Sandstone,
limestone
Heat, pressure
Cooling
Heat, pressure,
stress
Magma
(molten rock)
Melting
Metamorphic rock
Slate, marble,
gneiss, quartzite
Fig. 15-8, p. 343
Steps
Oxygen

The most abundant element in Earth’s
crust.
Nitrogen

The most abundant element in the Earth’s
atmosphere.
Iron

The most abundant element in the Earth’s
core.
Aluminum

The element commercially extracted from
bauxite
Relationships Between All Three
Rocks
 All three rocks are being
recycled and converted to all of
the classes
Rock Classification
Igneous

Description – forms the bulk of the earth’s
crust. It is the main source of many non-fuel
mineral resources.

Classification –
 Intrusive Igneous Rocks – formed from
the solidification of magma below
ground
 Extrusive Igneous Rocks – formed
from the solidification of lava above
ground
Igneous (Continued)

Examples – Granite, Pumice,
Basalt, Diamond, Tourmaline,
Garnet, Ruby, Sapphire
Sedimentary

Description – rock formed from
sediments. Most form when rocks
are weathered and eroded into small
pieces, transported, and deposited in
a body of surface water.
– pieces that are
cemented together by quartz and
calcium carbonate (Calcite).
Examples: sandstone (sand stuck
together), Conglomerate (rounded
& concrete-looking) and Breccia
(like conglomerate but w/ angular
pieces)
Clastic
Sedimentary (Continued)

Nonclastic –
 Chemical Precipitates – limestone
precipitates out and oozes to the
bottom of the ocean (this is why there
is a lot of limestone in S.A.)
 Biochemical Sediments – like peat &
coal
 Petrified wood & opalized wood
Metamorphic


Description – when preexisting rock is
subjected to high temperatures (which may
cause it to partially melt), high pressures,
chemically active fluids, or a combination
of these
Location – deep within the earth
Examples:

Contact Metamorphism- rock that is next to
a body of magma
Ex. limestone under heat becomes marble
through crystallization

Limestone -> marble
sandstone -> quartzite
shale -> hornfelds (slate)

Dynamic Metamorphism – earth movement
crushes & breaks rocks along a fault. Rocks
may be brittle- (rock and mineral grains are
broken and crushed) or it may be ductile(plastic behavior occurs.)

Rocks formed along fault zones are called
mylonites.
Metamorphic (Continued)

Regional Metamorphism – during
mountain building; great quantities of
rock are subject to intense stresses and
heat
Ex. cont. shelves ram together
Metamorphism – One
form of rock changing into another
Progressive
shale->slate->schist->gneiss
coal->graphite
granite->gneiss