* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Unit 4-Dynamic Crust PowerPoint
Survey
Document related concepts
Spherical Earth wikipedia , lookup
Schiehallion experiment wikipedia , lookup
Evolutionary history of life wikipedia , lookup
Post-glacial rebound wikipedia , lookup
Paleontology wikipedia , lookup
Tectonic–climatic interaction wikipedia , lookup
Magnetotellurics wikipedia , lookup
History of geomagnetism wikipedia , lookup
Geochemistry wikipedia , lookup
History of Earth wikipedia , lookup
Age of the Earth wikipedia , lookup
Physical oceanography wikipedia , lookup
Mantle plume wikipedia , lookup
History of geology wikipedia , lookup
Transcript
Unit 4 The Dynamic Crust 1 A. The Earth in Cross Section I. There are 4 major zones that make up the Earth: A._Lithosphere_______ : Outer, thinnest layer of the Earth. There are two types: 1. _Continental_____________ : __30km (18.6 mi.)__ -Thickness: Granite_______ -Composition: -Density: ___2.7g/cm3_____ 2. : __Oceanic______________ -Thickness: _5km (3.1mi.)__ -Composition: _Basalt______ -Density: __3.0g/cm3_______ 2 3 A. Crust Ocean composed of basalt Continent composed of granite that is that is 5 to 6 km thick up to 30 km thick 4 Mantle B. _________________: Found below the crust. Has two parts: Asthenosphere 1. _________________: Upper, “plastic” mantle. -partially melted material. 2. __________________: Rest of mantle; actual Stiffer Mantle temperature is below the melting point. NOTE: The boundary between the crust and mantle is called the __________________ Mohorovicic ________________________, or MOHO. Discontinuity Outer Core C. _________________: Only liquid layer of the earth. Composed mainly of iron. Inner Core D. _______________: Solid, innermost layer of Earth. Composed mainly of iron and nickel. 5 B. Mantle Asthenosphere Stiffer Mantle is is Partially melted Not melted 6 C. Outer Core Only liquid layer composed of Iron D. Inner Core Solid center of Earth composed of Iron and Nickel 7 B. Crustal Movement I. Dynamic Crust -The crust and outermost part of the Mantle is called the Lithosphere _________________ A. The first theory of crustal movement was introduced in Continental 1915 by Alfred Wegener, and was called _____________ Drift _____________________________________ --Evidence for this theory include: match up like a puzzle 1. Continents _____________________________ 2. Correlation of rock layers/fossils: Rock layers and fossils match up _____________________________________ on the edges of different continents. _____________________________________ 8 3. Mountain chains: ________________ Mountain chains on different continents match up. So do the _______________________________________ fossils found in the mountain chains. _______________________________________ _______________________________________ 4. Climate evidence: _________________ ______________________________________ Ice cores taken from glaciers on different continents match up. ______________________________________ ______________________________________ 9 5. Crustal age: ___________________ The age of oceanic crust matches up at equal distances from ______________________________________ mid-ocean ridges. ______________________________________ B.Sea Floor Spreading: _________________ Theory that the oceanic crust has ______________________________________ been constructed by material from deep within the Earth that ______________________________________ rises and spreads apart the mid-ocean ridges. Circulation of heated fluid 1. Convection cell: __________________ caused by differences in density. This is what moves the ______________________________________ plates. ______________________________________ 10 11 2. Evidence Rock that is closer to the mida. Igneous Ocean Rocks: ______________ ocean ridges is younger and age increases as distance from the ______________________________________ ridge increases. ______________________________________ ______________________________________ 12 Every 10,000 b. Magnetic Reversal: ________________ years, the Earth’s magnetic field ______________________________________ switches. This can be seen in the ______________________________________ magnetic minerals within the basalt ______________________________________ rock found on the ocean floor. ______________________________________ ______________________________________ ______________________________________ 13 Sea Floor Spreading driven by Convection Cells evidence Igneous Ocean rocks Magnetic Reversal 14 II. that Earth’s lithosphere is made up of C. Plate Tectonics:States __________________ a number of solid pieces, or plates, that __________________________________ move in relation to each other. Plate Boundaries 2 plates coming together A. Convergent: ____________________ --3 Types: Continental-continental 1. __________________________: Two continental plates coming together. Himalayan Mtns. (Indian-Australian and Eurasian Plate Ex: ______________________________ 15 II. Plate Boundaries A. Convergent Oceanic-continental 2. ______________________: Oceanic and Continental plates coming together. Island-arc --Typically will form an _____________ Oceanic trench along an ________________________ , where the ocean plate pushes under the continental plate. _________________ Ex: _____________________________ _______________________________________ 16 II. Plate Boundaries A. Convergent 3. _____________________: Two ocean plates coming Continental-Oceanic together. Ocean trench --Typically will form an _____________ as one plate pushes under the other. Ex: _____________________________ Peru-Chile Trench (Nazca and South American Plates 17 2 plates moving away from each B. Divergent: ______________________ other (Sea-floor spreading) ___________________________ -Usually form ____________________ Mid-Ocean Ridges Ex: ________________________ Mid-Atlantic Ridge (North American and Eurasian/African Plates 18 Plate Boundaries Plate Tectonics moving plates meet at Convergent come together Examples ContinentalOceanic OceanicOceanic ContinentalContinental 19 Plate Boundaries Divergent Move apart 20 I. Plate Boundaries 2 plates sliding past C. Transform Fault:___________________ each other _______________________________________ The Earth is cracked. -Forms where _____________________ _______________________________________ San Andreas Fault (Pacific and North American Plate Ex: ____________________________________ 21 Plate Boundaries Transform Move Horizontally Past Each Other 22 C. Evidence of Crustal Activity I. Crustal Activity A. Deformed Rock Strata --Originally, sedimentary rocks form ____ In horizontal layers called beds ______________________________________ However, observations made of Earth’s surface indicate that ___________________________________________________ The horizontal layers have been changed. This includes: Rocks are pushed up at an angle. 1. Tilting: _______________________________________ 23 2. Folding: __________________________ Bends in the rock layers due to ____________________________________ continental collisions. Breaks in rocks where plate 3. Faulting: __________________________ movement has occurred. ___________________________________ 24 B. Displaced fossils: ___________________ Fossils of organisms that lived in the sea _____________________________________ have been found on mountain tops. _____________________________________ II. Results of Crustal Activity A. Earthquakes: _____________________ Any shaking, or rapid motion of Earth’s solid _______________________________________ outer layers. _______________________________________ place underground where the --focus: The ____________________________ earthquake occurs. _______________________________________ The location at Earth’s surface --epicenter: _________________________ just above the focus. _______________________________________ 25 --Types of earthquake waves: P-waves 1. __________________: Also called compressional waves; the motion of the ground is parallel to the direction of wave Solids and Liquids motion. These waves can pass through ______________ __________________________________ 26 2. _______________: S-waves Also called longitudinal waves; the motion of the ground is perpendicular to the direction of wave motion. These waves can pass through _____________ SOLIDS ONLY ______________________________________ Surface Waves 3. ________________: Waves that ripple the surface of the Earth, causing most of the damage of an earthquake. 27 P-waves --When traveling through the same material, ___________ travel faster than ____________. S-waves speeds in different -Since these waves travel at different ________ types of ___________ materials, we can use earthquake waves to tell us about the __________________________. interior of the Earth. P-waves -When an earthquake occurs, both __________ and _________________. S-waves are given off In many places on Earth, both waves are received; however, in other places, only P-Waves are received _________________________. -Since S waves cannot pass through a liquid, the conclusion is some parts of the Earth’s that _______________________ interior are liquid. ______________________________________ 28 -If an earthquake occurs under the ocean, the energy is also released through the ocean water. When it reaches the coastline of a continent or island, it may form a large, fast moving wave called a Tsunami _________________. 500+ mph They may move at speeds of _________ and may be ____________________high!!! 20-100 feet 29 B. Earthquake Strength -The strength of an earthquake can be determined in one of two ways: Richter Scale 1. ______________: Used to describe the amount of energy released by an earthquake. It ranges from ___ 0 to ___, 10 and 32 each increase on the scale indicates a release of ____ times more energy!!! --To record earthquake waves, seismologists use a seismograph _______________, which can be used to record the arrival time of the waves and the intensity of the waves. 30 Mercalli Scale 2. __________________: Used to describe the earthquake in I to terms of the amount of damage done. It ranges from ___ XII These are based on personal accounts. ___. --Why is the Richter scale better to use when describing the intensity of an earthquake, rather than the Mercalli scale? _________________________ Because the Richter scale uses actual ____________________________________ measurements rather than the Mercalli ____________________________________ scale which uses personal accounts which can ____________________________________ change from person to person. 31 C. Volcanoes: --How do they form? 1. Molten rock from within the earth, called _______, along with gases, begins to rise up through cracks and weak spots in the crust. 2. When this molten material, along with gases from inside earth, break through the surface, it may flow out on the surface, and then it is called _____. --Where do they form? 1. __________________________________ _______________________________________ 2. __________________________________ 32 3. __________: Weak points in the crust, located over unusually high heat flow in the mantle. Although the crust may move, _____ _______________________________________ _______________________________________ -Ex: ________________________________ 33 34 35 Continental drift evidence puzzle fit of continents correlation of rock layers mountain chains climate evidence crustal age 36 crustal activity deformed rock strata tilting displaced fossils shallow fossils at high elevation deep fossils in shallow water areas folding faulting 37 results of crustal activity Earthquakes types of waves P waves S waves L waves 38 Earthquakes measured using Richter Scale Mercalli Scale 39 Volcanoes Shield Composite Cinder erupts erupts erupts lava lava and ash ash and cinder 40