Introduction to Earth’s Systems and Earth Science Plate Tectonics Review Introduction to Earth’s Systems and Earth Science Textbook pages 209-215

Earth and our Solar System _________ planet from the Sun 3rd life *only planet that can support ____________ *orbits the Sun in an ________ pattern/shape elliptical *takes ________ days to complete one orbit 365 *takes _____ hours to complete one rotation 24 *was formed _______ billion years ago 4.6

EARTH’S INTERACTIVE COMPONENTS LITHOSPHERE = makes up the Earth’s interior (rock) ATMOSPHERE = makes up the gases surrounding Earth (air) HYDROSPHERE= makes up the areas of water BIOSPHERE = makes up all the living things within the other parts EARTH IS AN INTEGRATED SYSTEM OF 4 INTERACTING COMPONENTS

HOW EARTH FORMED CAME FROM COSMIC DUST IN THE SOLAR SYSTEM (BIG BANG THEORY) ALL THE ELEMENTS FOUND ON EARTH ARE AS OLD AS EARTH EARLY EARTH WAS A HOT, MOLTEN SPHERE AS MOLTEN MATERIAL COOLED, THE ELEMENTS SEPARATED INTO LAYERS BASED ON MASS (HEAVY IRON TOWARDS THE CENTER) https://www.youtube.com/watch?v=BBwqendK8zc

EARTH LAYERS BECAUSE EARTH’S ELEMENTS SETTLED INTO PLACE BASED ON MASS…… EARTH IS DIVIDED INTO LAYERS 2 GROUPS OF LAYERS: COMPOSITIONAL LAYERS & PHYSICAL LAYERS KNOWLEDGE OF EARTH’S LAYERS *SEISMIC WAVES ANALYSIS *LAVA ANALYSIS *METERITE COMPOSITION

COMPOSITIONAL LAYERS OF EARTH: three major concentric zones of the earth CRUST = thinnest (only 0.5% of earth’s total mass), outermost layer, solid, brittle, coolest layer, mostly oxygen, oceanic (71%) & continental MANTLE = Mostly solid rock, medium density, has magma that circulates in convection cells. Mostly iron, magnesium, aluminum Includes the asthenosphere: hot, partly melted rock that flows and can be deformed like plastic CORE = innermost layer (solid surrounded by liquid) greatest density, hottest, mostly iron and nickel

PHYSICAL LAYERS OF EARTH 1. LITHOSPHERE = outer layer, includes crust and uppermost mantle, divided into tectonic plates 2. ASTHENOSPHERE = middle part of mantle, flexible, rock flows slowly 3. MESOPHERE = lower part of mantle 4. OUTER CORE = outer part of core, dense liquid nickel and iron 5. INNER CORE = inner most part of core, dense solid nickel and iron due to pressure, over 4000 ° C

Comparison of the Compositional and Physical Layers: The compositional layer is defined by the chemical composition of the layers and the physical layer is defined by the layers’ physical properties (solid, liquid, or how waves move through the layer). Physical Layers

What is plate tectonics? If you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.

The Earth’s crust is divided into 15 major plates which are moved in various directions. This plate motion causes them to collide, pull apart, or scrape against each other. Each type of interaction causes a characteristic set of Earth structures or “tectonic” features. The word, tectonic, refers to the deformation of the crust as a consequence of plate interaction.

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

World Plates This diagram shows the major Tectonic Plates. Presenter: Point out the UK, sitting on the Eurasian Plate. Also the plate boundary between Africa and South America (note that it has the same shape as the coastlines in these countries).

What are tectonic plates made of? Plates are made of rigid lithosphere. The lithosphere is made up of the crust and the upper part of the mantle. Plates are made of rigid lithosphere – formed of the crust and the extreme upper mantle (point out these layers on the figure).

What lies beneath the tectonic plates? Below the lithosphere (which makes up the tectonic plates) is the asthenosphere. The asthenosphere, beneath the lithosphere, is part of the upper mantle and is so hot that it is 1 – 5% liquid (I.e. 95 – 99% solid). This liquid, usually at the junctions of the crystals, allow it to flow – which is why ‘astheno’ means weak.’ Beneath the asthenosphere is the rest of the mantle, which is completely solid – but can also flow (on geological time scales) because of the intense temperatures and pressures involved. The base of the lithosphere-asthenosphere boundary corresponds approximately to the depth of the melting temperature in the mantle. The plastic layer below the lithosphere The plates of the lithosphere float on the asthenosphere

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 The Earth beneath your feet is moving……. 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’s Crust Is Made Up of a Mosaic of Huge Rigid Plates: Tectonic Plates http://www.hhmi.org/biointeractive/plate-tectonics

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)

Island Arc Formation & The “Ring of Fire” http://study.com/academy/lesson/island-arc-definition-formation.html (The whole video won’t play, it’ll get cut-off with a “subscription,” but the beginning is great!)

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 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 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 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