Transcript Explain how plate tectonics and the rock cycle - science-b

AP Environmental
Science
Mr. Grant
Lesson 20
Earth’s Physical Systems:
Matter, Energy, and Geology
Geology: The Physical Basis For
Environmental Science
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Objectives:
• Define the terms lithosphere and rock cycle.
• Explain how plate tectonics and the rock cycle shape the
landscape around us and the earth beneath our feet.
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Define the terms lithosphere and rock cycle.
Lithosphere: The outer layer of earth, consisting of curst
and uppermost mantle. More generally the solid part of
the Earth, including rocks, sediment, and soil at the
surface and extending down many miles underground.
Rock Cycle: The very slow process in which rocks and
the minerals that make them up are heated, melted,
cooled, broken, and reassembled, forming igneous,
sedimentary, and metamorphic rocks.
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Explain how plate tectonics and the rock cycle shape
the landscape around us and the earth beneath our feet.
• Earth’s geology is dynamic, and a human lifetime is a blink of
the eye in the long course of geological time.
• Earth consist of distinct layers that differ in composition,
temperature, density, and other characteristics.
• Plate tectonics is a fundamental system that shapes Earth’s
physical geography, as well as producing earthquakes and
volcanoes.
• Tectonic plates meet at three types of boundaries: divergent,
transform, and convergent.
• Matter is cycled within the lithosphere, and rocks transform from
one type to another.
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Geology
• Physical processes at and below the Earth:
- Shape the landscape
- Lay the foundation for environmental systems and
life
- Provide energy from fossil fuels and geothermal
sources
• Geology = the study of Earth’s physical features,
processes, and history
- A human lifetime is just the blink of an eye in
geologic time
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The geologic record
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Our plant consists of layers
• Core = solid iron in the center
- Molten iron in the outer core
• Mantle = less dense, elastic rock
- Aesthenosphere: very soft or
melted rock
- Area of geothermal energy
• Crust = the thin, brittle, lowdensity layer of rock
• Lithosphere = the uppermost
mantle and the crust
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Plate tectonics
• Plate tectonics = movement of lithospheric plates
- Heat from Earth’s inner layers drives convection
currents
- Pushing the mantle’s soft rock up (as it warms) and
down (as it cools) like a conveyor belt
- The lithosphere is dragged along with the mantle
- Continents have combined, separated, and
recombined over millions of years
• Pangaea = all landmasses were joined into 1
supercontinent 225 million years ago
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The Earth has 15 major tectonic plates
Movement of these plates influences climate and evolution
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Earth’s crust is created and destroyed
• Divergent plate boundaries
- Magma rises to the surface
- Pushing plates apart
- Creating new crust
- Has volcanoes and
hydrothermal vents
• Transform plate boundaries
- Two plates meet, slipping and
grinding
- Friction spawns earthquakes
along strike-slip faults
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Tectonic plates can collide
• Convergent plate boundaries = where plates collide
• Subduction = the oceanic plate slides beneath
continental crust (e.g. the Cascades, Andes Mountains)
- Magma erupts through the surface in volcanoes
• Continental collision = two plates of continental crust
collide
- Built the Himalaya and Appalachian Mountains
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Plate tectonics produces Earth’s landforms
• Tectonics builds mountains
- Shapes the geography of oceans, islands, and
continents
- Gives rise to earthquakes and volcanoes
- Determines locations of geothermal energy sources
• Topography created by tectonics shapes climate
- Altering patterns of rain, wind, currents, heating,
cooling
- Thereby affecting the locations of biomes
- Influencing where animals and plants live
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The rock cycle
• Rock cycle = the heating, melting, cooling, breaking,
and reassembling of rocks and minerals
• Rock = any solid aggregation of minerals
• Mineral = any element or inorganic compound
- Has a crystal structure, specific chemical
composition, and distinct physical properties
• Rocks help determine soil characteristics
- Which influences the region’s plants community
• Helps us appreciate the formation and conservation of
soils, minerals, fossil fuels, and other natural resources
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Igneous rock
• Magma = molten, liquid rock
• Lava = magma released from the
lithosphere
• Igneous rock = forms when
magma cools
• Intrusive igneous rock = magma
that cools slowly below Earth’s
surface (e.g. granite)
• Extrusive igneous rock = magma
ejected from a volcano (e.g. basalt)
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Sedimentary rock
• Sediments = rock particles
blown by wind or washed
away by water
• Sedimentary rock =
sediments are compacted or
cemented (dissolved minerals
crystallize and bind together)
- Sandstone, limestone, shale
• Lithification = formation of
rock (and fossils) through
compaction and crystallization
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Metamorphic rock
• Metamorphic rock = great
heat or pressure on a rock
changes its form
• High temperature reshapes
crystals
- Changing rock’s appearance
and physical properties
• Marble = heated and
pressurized limestone
• Slate = heated and pressurized
shale
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TED Video
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David Gallo on life in the deep oceans (13:23)
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