Plate Tectonics Review Textbook pages Tuesday, November 3 rd 2015

The Earth Is a Dynamic Planet  Three major concentric zones of the earth  Core: solid inner part surrounded by a liquid Mantle: mostly solid rock  Including the asthenosphere: hot, partly melted rock that flows and can be deformed like plastic  Crust  Continental crust & Oceanic crust (71% of crust)

Plate tectonics are responsible for Major Features of the Earth’s Crust and Upper Mantle

The Earth beneath your feet is moving…….  Tectonic Plates: huge rigid plates move extremely slowly atop the denser mantle on hot, soft rock in the underlying asthenosphere  Convection cells: move large volumes of rock and heat in loops within the mantle like gigantic conveyer belts

 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  Continents have combined, separated, and recombined over millions of years (Pangaea = all landmasses were joined into a supercontinent 225 million years ago) The Earth beneath your feet is moving…….

The Earth’s Crust Is Made Up of a Mosaic of Huge Rigid Plates: Tectonic Plates

Fig. 14-4, p. 347 EURASIAN PLATE NORTH AMERICAN PLATE ANATOLIAN PLATE JUAN DE FUCA PLATE CARIBBEAN PLATE PHILIPPINE PLATE CHINA SUBPLATE AFRICAN PLATE ARABIAN PLATE INDIA PLATE PACIFIC PLATE COCOS PLATE SOUTH AMERICAN PLATE NAZCA PLATE AUSTRALIAN PLATE SOMALIAN SUBPLATE SCOTIA PLATE ANTARCTIC PLATE Transform faults Divergent plate boundaries Convergent plate boundaries The Earth’s Major Tectonic Plates

Three types of boundaries between plates Divergent plates – plates move apart Magma – flows up through the resulting cracks forms new rocks (seafloor spreading) Oceanic ridge – some of which have higher peaks and deeper canyons than earth’s continents

Three types of boundaries between plates Convergent plates – two plates collide Oceanic & Continental: oceanic plate slides under the continental crust (subduction) Magma erupts through the surface in volcanoes as a result of subduction Continental & Continental: crust may lift up from both plates (uplift) to form mountains Trench: forms at the boundary between the 2 converging plates

Creation of a Volcano

Volcanoes Release Molten Rock from the Earth’s Interior Volcano: magma reaches the earth’s surface through a fissure (crack) Lava: magma that reaches the earth’s surface. Debris ranging from large chunks of larva rock to glowing hot ash, liquid lava and gases such as water vapor, carbon dioxide and sulfur dioxide. Much of the world’s volcanic activity is concentrated along the boundaries of the earth’s tectonic plates Benefits of volcanic activity: highly fertile soil, creates outstanding landforms (Crater Lake, OR)

Three types of boundaries between plates Transform fault boundary (e.g. San Andreas fault): where plates slide and grind past one another along a fault (fracture in the rock) Fault zones are where movement has occurred Most located on the ocean floor The San Andreas Fault as It Crosses Part of the Carrizo Plain in California, U.S.

Earthquakes Are Geological Rock-and-Roll Events Richter scale Insignificant: <4.0 Minor: 4.0–4.9 Damaging: 5.0–5.9 Destructive: 6.0–6.9 Major: 7.0–7.9 Great: >8.0 Earthquake – occur when rocks rupture (epicenter) unexpectedly along a fault (seismic activity) Seismic waves – waves of energy Magnitude – measures the size of the earthquake as it relates to the amplitude of the energy wave & distance Foreshocks and aftershocks Primary effects of earthquakes: shaking, permanent vertical or horizontal displacement of the ground

Major Features and Effects of an Earthquake

Areas of Greatest Earthquake Risk in the United States

Areas of Greatest Earthquake Risk in the World

Earthquakes on the Ocean Floor Can Cause Huge Waves Called Tsunamis  Tsunami, tidal wave: generated when part of the ocean floor suddenly rises or drops. Usually occurs offshore in subduction zones.  Detection of tsunamis: by ocean buoys, pressure recorders on the ocean floor which measures changes in water pressure as the waves pass over it; data relayed via satellites tsunami warning systems

Some Parts of the Earth’s Surface Build Up and Some Wear Down Internal geologic processes Generated by heat from the earth’s interior, generally build up the earth’s surface in the form of continental and oceanic crust including mountains and volcanoes External geologic processes Weathering : driven directly or indirectly by energy from the sun(mostly in the form of flowing water and wind) Physical, Chemical, and Biological Erosion: Wind, Flowing water, Human activities

Weathering: Biological, Chemical, and Physical Processes

Earth’s Major Geological Processes and Hazards  Gigantic plates in the earth’s crust move very slowly atop the planet’s mantle, and wind and water move the matter from place to place across the earth’s surface.  Natural geological hazards such as earthquakes, tsunamis, volcanoes, and landslides can cause considerable damage.

Earth’s Rocks are Recycled……..  The three major types of rocks found in the earth’s crust — sedimentary, igneous, and metamorphic — are recycled very slowly by the process of erosion, melting, and metamorphism.

There Are Three Major Types of Rocks  Earth’s crust is composed of minerals and rocks  Three broad classes of rocks, based on formation Sedimentary Igneous Sandstone Granite Shale Lava rock DolomiteMetamorphic Slate Anthracite Lignite Slate Bituminous coal Marble Leave space under each rock type for in-class and homework notes!

The Earth’s Rocks Are Recycled Very Slowly  Rock cycle: the interaction of physical and chemical processes that change rocks from one type to another. Slowest of the earth’s cyclic processes

The Life of a Rock Sedimentary Rock Metamorphic Igneous Changes are made from pressure and heat. Layers of sediment join together. Melted rock cools and hardens

Rocks become smaller, and smaller, and smaller, and smaller...  By erosion  By wind  By earthquake  By floods  By rain  By slides  By man Rocks change…………..  By earthquakes  By volcanoes  By heat and pressure

 Weathering: the breaking up of rocks and soil into different products (clay, sand, rock fragments like pebbles & stones)  Erosion: the moving of weathered rock and soil. Weathering allows erosion to take place.

Sedimentary Rock is...  Rock formed when layers of small particles of shell, rock, and sand join together. Types of Sedimentary Rocks Include… Gypsum Sandstone Shale Limestone Conglomerate

Sedimentary Rocks How They are Made  Wind and water break down the earth  Bits of earth settle in lakes and rivers  Layers are formed and build up  Pressure and time turn the layers to rock

Metamorphic Rock is...  Rock that is formed when pressure and heat create changes to sedimentary or igneous rock. Types of Metamorphic Rocks

Metamorphic Rocks What are They?  Rocks that have changed  They were once igneous or sedimentary  Pressure and heat changed the rocks

Igneous Rock is...  Rock that is formed when melted rock cools and hardens. Types of Igneous Rocks Granite

Igneous Rocks What are They?  Fire Rocks  Formed underground by trapped, cooled magma  Formed above ground when volcanoes erupt and magma cools

 With your group, share your rock type posters. Take notes on each type in your notebook – including your own!  After you’ve shared, complete the Rock Cycle Activity.