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