unit 1: earth as a system - kalaheo...
TRANSCRIPT
Section 1: Plate Tectonics and the Rock Cycle
Unit 1: Earth as a System
Earth’s Realms● Earth is divided into 4 major realms:
▪ Atmosphere – gases surrounding earth
▪ Hydrosphere - earth’s supply of water
▪ Lithosphere - soil and rock of the earth’s crust
▪ Biosphere – contains earth’s communities, ecosystems, and landscapes; relies on the other three realms for survival.
● The earth’s consists of:● Core: innermost zone with solid inner core
and molten outer core that is extremely hot; made primarily of Iron and Nickel
● Mantle: solid rock with a less-rigid outer part (asthenosphere) that is melted, pliable rock.
● Crust: Outermost zone which underlies the continents; the most abundant element in Earth’s crust is Oxygen.
Internal Planetary Processes
Internal Planetary Processes
▪ Layers of the earth that directly affect us▪ Lithosphere
▪ Outermost rigid rock layer made up of tectonic plates
▪ Asthenosphere▪ Upper mantle
comprised of hot, soft rock
Internal Planetary Processes
▪ Plate Tectonics- study of the processes by which the lithospheric plates move over the asthenosphere▪ Plate Boundary - where 2 plates meet▪ Divergent▪ Convergent▪ Transform
Fig. 15-2, p. 336
Volcanoes
Folded mountain belt
Abyssal floor
Oceanic ridge
Abyssal floor TrenchAbyssal hills
Craton
Abyssal plain
Oceanic crust (lithosphere)
Continental shelf
Abyss
al pl
ain
Continental slope
Continental rise
Continental crust (lithosphere) Mantle (lithosphere)
Mantle (lithosphere)
Mantle (asthenosphere)
Spreading center Ocean
trench
Plate movement
Subduction zone
Oceanic crust
Continental crust
Continental crust
Material cools as it reaches
the outer mantle
Cold dense material falls back through
mantleHot
material rising
through the
mantle
Mantle convection
cell
Two plates move towards each other. One is subducted back into the mantle on a falling convection current.
Mantle
Hot outer core Inner
core
Plate movement
Collision between two continents
Tect
onic
plat
e
Oceanic tectonic
plateOceanic tectonic plate
Oceanic crust
●Divergent boundary –plates move apart in opposite directions.
●Example: Mid-Atlantic Ridge
■Convergent boundary – the plates push together. At most convergent plate boundaries, the oceanic lithosphere is carried downward under an island or continent, creating a subduction zone. Earthquakes are common here. ■Can also lead to formation of a volcanic mountain range.■Example: Japan, Himalayas
● Transform boundary – plates move horizontally in opposite but parallel directions.
● Plates snag on one another and build pressure, then release dramatically!
● The San Andreas (CA) Fault is an example of a transform fault.
GEOLOGIC PROCESSES
Fig. 15-4b, p. 338
Trench Volcanic island arc Craton
Transform fault
LithosphereSubduction zone
Lithosphere Lithosphere
Asthenosphere Asthenosphere Asthenosphere
Divergent plate boundaries Convergent plate boundaries Transform faults
Rising magma
Fig. 15-4a, p. 338
EURASIAN PLATENORTH AMERICAN PLATE
ANATOLIAN PLATE
JUAN DE FUCA PLATE
CHINA SUBPLATE
CARIBBEAN PLATE
PHILIPPINE PLATE
ARABIAN PLATEAFRICAN
PLATEPACIFIC PLATE SOUTH
AMERICAN PLATENAZCA
PLATEINDIA-
AUSTRALIAN PLATE
SOMALIAN SUBPLATE
ANTARCTIC PLATE
Divergent plate boundaries
Convergent plate boundaries
Transform faults
Pacific Ring of Fire
Earthquakes
▪ Caused by the release of accumulated energy as rocks in the lithosphere suddenly shift or break▪ Occur along faults (often at plate boundaries)▪ Energy released as seismic waves
Tsunami
▪ Giant undersea wave caused by an earthquake, volcanic eruption or landslide▪ Travel > 450 mph
▪ Tsunami wave may be 1m deep in ocean▪ Becomes 30+m high on shore
▪ Magnitude 9.3 earthquake in Indian Ocean (2004)▪ Triggered tsunami that killed over 230,000
people in South Asia and Africa
● Volcanoes occur in three locations:● Subduction zones (convergent plate
boundaries)● Divergent plate boundaries● Hot spots (Hawai’i)
● Location on crust where magma reaches surface as lava.
Volcano
The Rock Cycle
● The interaction of processes that change rocks from one type to another
● Three types of rocks:● Igneous● Sedimentary● Metamorphic
● All three types of rocks are being recycled and converted to the others
The Rock Cycle
Fig. 15-8, p. 343
ErosionTransportation
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
● Description – forms the bulk of the earth’s crust. It is the main source of many non-fuel mineral resources; Formed by the cooling of magma/lava.
● Classification – ● Intrusive Igneous Rocks – formed from the
crystalization of magma below ground (Granite, Gemstones, etc.)
● Extrusive Igneous Rocks – formed from the solidification of lava above ground (Pumice, Obsidian, etc.)
Igneous Rock
●Description – rock formed from the deposition of sediments. Most form when rocks are weathered and eroded into small pieces, transported, and deposited.
Sedimentary Rock
●Description – when preexisting rock is subjected to high temperatures (which may cause it to partially melt) and/or high pressures, it forms metamorphic rock
●Location – deep within the earth
Metamorphic Rock
■Progressive Metamorphism – One form of rock changing into another. Examples:
■shale->slate->schist->gneiss
■coal->graphite->diamond
■granite->gneiss
Primary vs. Secondary SuccessionDuring
succession organisms
modify their surroundings which in turn
creates suitable
conditions for succeeding organisms
Following major changes in the surface of the planet, primary succession begins…
Primary vs. Secondary Succession (cont.)
Secondary succession begins on the soil where there was living organisms previously, but have vanished due to natural or
anthropogenic (human-made) causes