Presentation on theme: "BIG IDEA 6: Earth Structures"— Presentation transcript:
1 BIG IDEA 6: Earth Structures Description Over geologic time, internal and external sources of energy have continuously altered the features of Earth by means of both constructive and destructive forces. All life, including human civilization, is dependent on Earth's internal and external energy and material resources.
2 Benchmark Number & Descriptor SC.7.E.6.1Describe the layers of the solid Earth, including the lithosphere, the hot convecting mantle, and the dense metallic liquid and solid cores.SC.7.E.6.2Identify the patterns within the rock cycle and relate them to surface events (weathering and erosion) and sub-surface events (plate tectonics and mountain building).SC.7.E.6.3Identify current methods for measuring the age of Earth and its parts, including the law of superposition and radioactive dating.SC.7.E.6.4Explain and give examples of how physical evidence supports scientific theories that Earth has evolved over geologic time due to natural processes.SC.7.E.6.5Explore the scientific theory of plate tectonics by describing how the movement of Earth's crustal plates causes both slow and rapid changes in Earth's surface, including volcanic eruptions, earthquakes, and mountain building.SC.7.E.6.6Identify the impact that humans have had on Earth, such as deforestation, urbanization, desertification, erosion, air and water quality, and changing the flow of water.SC.7.E.6.7Recognize that heat flow and movement of material within Earth causes earthquakes and volcanic eruptions, and creates mountains and ocean basins.
4 EARTH’S LAYERS The Earth is divided into FOUR main layers: Crust MantleOuter CoreInner Core
5 EARTH’S CRUST Outer layer of Earth’s surface Makes up 1% of Earth 2 types of crust:OceanicContinentalEarth’s crust is broken down into pieces known as tectonic plates.
6 Mantle Earth’s largest layers Made mostly of silicon, oxygen, magnesium and ironPieces of mantle can be obtained by erupting volcanoes.
7 OUTER CORE Is about 3000 miles beneath the Earth’s crust Said to be made up of molten lavaIronNickelThis lava flows very slowly inside the Earth, creating a magnetic field.
8 INNER CORE Deepest part of Earth Smallest section inside Earth Solid mass due to intense pressurecomposed of iron and nickel
9 BOUNDARIES between LAYERS Moho DiscontinuityLocated between the crust and mantlePlastic Like LayerPart of the upper mantleShadow ZonePart of the liquid outer core
10 KNOWLEDGE CHECK How many layers make up Earth? Which layer of Earth contains tectonic plates?Which is Earth’s largest layer?Which elements in Earth’s core helps create a magnetic field?
11 KNOWLEDGE CHECK How many layers make up Earth? 4 Which layer of Earth contains tectonic plates? Earth’s crustWhich is Earth’s largest layer? MantelWhich elements in Earth’s core helps create a magnetic field? Nickel and Iron
13 Earth’s Past and Future Earth has been transforming for the past 4.5 million years.The energy for this constant transformation comes from the Earth's molten interior.Earth will probably continue to evolve for another 4-5 billion years into the future.This energy from Earth’s interior has driven the Earth's physical/chemical evolution, and been ultimately responsible for all the rocks, continents, mountains, foreland basins, etc.
14 The Rock Cycle Rocks are naturally occurring. Rocks contain minerals, organic material, and glass.There are 3 types of rocks:IgneousMetamorphicSedimentaryEach type of rock can become a new type by traveling through the rock cycle.
15 IGNEOUS ROCKS Origins: Types of Lava/Magma: Come from volcanoesWhen magma(inside)/Lava (outside) coolTypes of Lava/Magma:Due to location of VolcanoBasaltic – Hawaii, non-explosive volcanoesAndesitic – Pacific ocean volcanoesGranitic – very explosive volcanoesCategories of Igneous Rocks:IntrusiveFormed inside EarthFound when volcano erupts and are pushed out or through miningContain large mineral grainsExtrusiveForm outside surfaceLava cools quicklyRocks generally contain holes; gas escapes
16 EXAMPLES OF IGNEOUS ROCKS Granite: Igneous, IntrusiveObsidian - volcanic glass that is formed by very rapid cooling of lavaPumice is lava that had a lot of gases in it and cooled quickly on the surface of the Earth.
17 METAMORPHIC ROCKS Origin: Rocks that form from change in temperature and pressureEarth Processes:Heat and PressureRocks are beneath the surface; heat and pressure increases.Rocks do not melt, but they do exchange minerals creating new rocks.FluidsFluids carrying dissolved minerals react with rocks.Chemical reaction occurs, and new rocks are formed.Earth’s RelationThey can form from tectonic processes such as continental collisions.They are also formed when rock is heated up by the intrusion of hot magma from the Earth's interior.Metamorphic rocks become exposed at the Earth's surface by erosion and uplift.Studying metamorphic rocks tells us about the temperatures and pressures that occur at great depths within the Earth's crust.
18 EXAMPLES OF METAMORPHIC ROCK FoliatedMineral grains are flattened into layer.Example - GNEISS: A foliated rock usually made from some type of graniteNon-FoliatedSmooth texture, no layersExample - Quartzite
19 SEDIMENTARY ROCKS Rocks created from sediments. Materials that make up sediments:Weathered and eroded rockPlant and animal remainsMinerals that fall out of solutionRelationship to EarthSediments are formed by both weathering and erosion.Sediments are then transported to their place of deposition by water, wind, mass movement, or glaciers.Ways sedimentary rocks form:CompactionSediments are pressed together.CementationSediments are glued together.Deposition of mineralsMinerals in solution are left when water evaporates.
20 EXAMPLES OF SEDIMENTARY ROCKS DETRITAL:Made of broken fragments of other rocksCHEMICAL:Made of minerals dissolved in solutionBIOCHEMICAL:Made of the remains of once-living thingsBreccia composed of sharp angled fragmentsRock Salt: This is an evaporate after the water evaporated from saltwater.Fossillferous Limestone contains fossils of various fresh and or salt water shell fish.
21 KNOWLEDGE CHECK Where is the beginning of the rock cycle? NAME THAT ROCK:This rock is formed from organic, inorganic, and rock fragments.This rock is formed from heat and pressure.This rock is formed from molten lava/magma.
22 KNOWLEDGE CHECKWhere is the beginning of the rock cycle? It is a cycle; therefore, there is no true beginning or end.NAME THAT ROCK:This rock is formed from organic, inorganic, and rock fragments. SedimentaryThis rock is formed from heat and pressure. MetamorphicThis rock is formed from molten lava/magma. Igneous
24 HOW OLD IS EARTH? Rocks are an open window to Earth’s past. James Hutton (18th century) believed Earth had to be much older then what was originally thought – probably millions of years old.He proposed his principle of Uniformitarianism.Big Idea:Geological processes that we see occurring today are the same processes that occurred in the past.
25 DATING EARTH LAW of SUPERPOSITION Superposition refers to, “placing on top of each other.”Scientists use the Law of Superposition to determine whether a fossil or a layer of rock is older or younger than another fossil or layer of rock.This law states that in a series of sedimentary rock layers, younger rocks normally lie on top of older rocks.
26 DATING EARTH RADIOACTIVE DATING Carbon – 14 Scientist use the decay of radioactive elements to determine the age of rocks.Radiometric dating indicates that the Earth is about billion years oldRadioactive Decay:Unstable elements that breakdown, or decay, by releasing particles and energy in the process and form another elementCarbon – 14Used to find the absolute age of rocksCarbon-14 has a half-life of 5730 years.It is only useful for dating materials that contain Carbon and lived no more than 50,000 years ago.
27 KNOWLEDGE CHECK Describe the principle of Uniformitarianism. When looking at a cross-section of the Grand Canyon, layers are noticed. What law best describes these layers?What element must be present in order to use radioactive dating?
28 KNOWLEDGE CHECKDescribe the principle of Uniformitarianism. Geological processes that we see occurring today, are the same processes that occurred in the past.When looking at a cross-section of the Grand Canyon, layers are noticed. What law best describes these layers? Law of SuperpositionWhat element must be present in order to use radioactive dating? Carbon-14
30 HOW DID THAT GET HERE? The Earth is said to be 4.57 billion years old. In order for Earth to look the way it does today many factors are taken into consideration.Physical geology is the study of the Earth's rocks, minerals, and soils and how they have formed through time.Complex internal processes such as plate tectonics and mountain-building have formed these rocks and brought them to the Earth's surface.Earthquakes are the result of the sudden movement of crustal plates, releasing internal energy that becomes destructive at the surface.Internal heat and energy are released also through volcanic eruptions.External processes such as glaciation, running water, weathering, and erosion have formed the landscapes we see today.
31 EVIDENCE of EARTH’S EVOLUTION TYPES of EVIDENCEEXAMPLES of EVIDENCEEvidence located at PLATE BOUNDARIESEvidence left behind from WEATHERINGEvidence left behind from EROSION AND DEPOSITIONHimalayas, Andes, Hawaiian Islands – all found at different plate boundaries.Stalactites and stalagmites are the remains of rocks which went through chemical weathering.Gullys, deltas, valleys, sand dunes, landslides are created through time as a result of moving water, ice, wind, and gravity.
32 EVIDENCE of EARTH’S EVOLUTION TYPES of EVIDENCEEXAMPLES of EVIDENCEEvidence from LANDFORMS - PANGEAEvidence of FOSSILSEvidence from CLIMATEMountain ranges in Africa line up with those in South America.Fossils of the plant Glossopteris found in rocks on widely separated landmassesFossils of tropical plants found near Arctic Circle
33 KNOWLEDGE CHECK Approximately how old is planet Earth? List and explain 4 pieces of evidence supporting Earth’s evolution.
34 KNOWLEDGE CHECKApproximately how old is planet Earth? The Earth is said to be 4.57 billion years old.List and explain 4 pieces of evidence supporting Earth’s evolution.Pangaea – Super continentFossils – Similar fossils found in different areasErosion and Deposition – formation of gullies, deltas, valleys, etc.
36 PLATE TECTONICSThe Earth’s crust and upper mantle are broken into sections called plates.Plates move around on top of the mantle like rafts in a pool.Earth’s plates are located on the lithosphere (crust and upper mantle).The average thickness of a plate is 100 km (62 miles).Most plates support both continent and ocean.
37 Alfred WegenerProposed a theory stating that in the distant past, the Earth’s continents were all joined as a single landmass.When Wegener placed all the continents together like a puzzle, it formed a large landmass which he called Pangaea.Wegener stated that this supercontinent began to break up about 200 million years ago.
38 PLATE BOUNDARIESEarth’s crust is made up of 7 major plates and several smaller ones.Where the edges of these plates meet is known as a PLATE BOUNDARY.How the plates are moving determines what type of boundary is between them.
39 TYPES of BOUNDARIES CONVERGENT BOUNDARY Plates collide into each other.These collisions produce mountains, earthquakes, and volcanoes.Example:Andes MountainsAleutians IslandsCONVERGENT BOUNDARY
40 3 TYPES of CONVERGENT BOUNDARIES Ocean plate colliding with a less dense continental plateSubduction Zone: where the less dense plate slides under the more dense plateVOLCANOES occur at subduction zones.Example: Andes Mountains2. Ocean plate colliding with another ocean plateThe less dense plate slides under the more dense plate creating a subduction zone called a TRENCHExample: Aleutian Islands3. A continental plate colliding with another continental platea place where folded and thrust faulted mountains formExample: Himalayas
42 TYPES of BOUNDARIES DIVERGENT BOUNDARY Plates move away from each other.Most of these boundaries are found in the oceans.At divergent boundaries, mid-ocean ridges and rifts are formed.DIVERGENT BOUNDARY
43 DIVERGENT BOUNDARYThe best known of the divergent boundaries is the Mid-Atlantic Ridge.This submerged mountain range extends from the Arctic Ocean to beyond the southern tip of Africa.The rate of spreading along the Mid-Atlantic Ridge averages about 2.5 centimeters per year (cm/yr) or 25 km in a million years.
44 TYPES of BOUNDARIES TRANSFORM BOUNDARY Plates slide past each other.The sliding of these plates causes rocks to rub against each other. At times, these rocks break and inch past each other. These breaks are felt as earthquakes.TRANSFORM BOUNDARY
45 TRANSFORM BOUNDARYThe San Andreas Fault is a result of the Pacific and North American plates sliding past each other.These plates are moving at about 5cm a year.
46 KNOWLEDGE CHECK Explain the theory of plate tectonics. How many plate boundaries are there?Name the type of plate boundary each feature is located at:Andes MountainsMid-Ocean RidgeSan-Andrea’s Fault
47 KNOWLEDGE CHECKExplain the theory of plate tectonics. Earth’s crust is broken up into plates which float on top of the mantle. The plates support the continents and oceans.How many plate boundaries are there? types of plate boundariesName the type of plate boundary each feature is located at:Andes Mountains - ConvergentMid-Ocean Ridge - DivergentSan-Andrea’s Fault - Transform
48 MOUNTAINS, VOLCANOES, EARTHQUAKES – HOW THEY FIT IN THE PICTURE
49 Convection CurrentsHot magma in the Earth moves toward the surface, cools, then sinks again.This movement creates convection currents beneath the plates that cause the plates to move.When the plates move, mountains, earthquakes, and volcanoes form.
50 MOUNTAINSMountains are formed when uplift occurs (Forces within the crust lift the land above).3 types of mountains can form due to plate movement:Folded mountainsFault-Block mountainsVolcanic mountainsYes, volcanoes are considered mountains.
51 FAULT-BLOCK Mountains MOUNTAIN FORMATIONFOLDED MountainsFAULT-BLOCK MountainsFolded mountains are formed by crust which have been uplifted and folded by compressional forces.These mountains occur along convergent plate boundaries either between continental plates or between an oceanic and a continental plate.Examples:RockiesAndesAlpsHimalayasThese mountains form when faults or cracks in the Earth's crust force some materials or blocks of rock up and others down.Instead of the Earth folding over, the blocks are stacked.Examples:Sierra Nevada Mts.Harz Mts.
52 VOLCANOES INFORMATION WHY THEY EXPLODE Volcanoes form when material from inside the Earth reaches the surface.Magma: Molten rock found inside the EarthLava: Molten rock when outside surface is reachedVolcanoes are most commonly found at both convergent and divergent plate boundaries.A major belt of volcanoes is the “Ring of Fire” which encircles the Pacific Ocean.Temperatures in the mantle are hot enough to melt rock into magma .Since magma is less dense than the solid rock around it, magma rises and some of it collects in magma chambers.As the magma rises, pressure decreases allowing trapped gasses to expand and propel the magma through openings in the Earth’s surface causing an eruption.
53 3 TYPES OF VOLCANOES SHEILD VOLCANOES CINDER CONE VOLCANOES Broad shaped, quiet eruptionsExamples: Kilauea, Hawaii and Mt. Etna, ItalyCINDER CONE VOLCANOESSteep sided, explosive eruptions (usually throws lava and rock high into the air)Example: Paricutin, MexicoCOMPOSITE VOLCANOESSteep sided, eruptions vary from quiet to explosiveExample: Mt. St. Helens
54 1943 Eruption of Paricutin – Mexico TYPES OF VOLCANOES1943 Eruption of Paricutin – MexicoCinder cone VolcanoMt. Etna, ItalyShield VolcanoMt. St. Helens, 1982Composite Volcano
55 ENVIRONMENTAL EFFECTS Earth’s surface is greatly affected by volcanoes.LANDAIRWATERLavaPoisonous gassesHot SpringsVolcanic AshAcid RainGeysersLandslidesHazeDeep Sea VentsMudflowsLower TempsFumaroles
56 EARTHQUAKESEarth’s crust movement causes stress among rocks under its surface.Stress can cause rocks to bend and stretch.Eventually rocks will break away from one another.Area in which the rocks break and move is called a fault.When rocks break, vibrations are produced called an earthquake.
57 Elastic Rebound Theory Explains how energy is stored in rocksRocks bend until the strength of the rock is exceeded.Breaks occurs and the rocks quickly rebound to an undeformed shape.Energy is released in waves that radiate outward from the fault.Fault: surface that rocks/plates move along
58 ROCKIN ‘N’ ROLLIN FOCUS SEISMIC WAVES Location where the earthquake energy is released inside the Earth.At the focus, seismic waves are produced and sent out.What we feelPrimary Waves (P Waves)Travel through rocksTake a straight pathMove the fastestSecondary Waves (S Waves)Causes rocks to vibrateTakes a straight pathRocks move up/downSurface WavesMove above groundMove up/down and side/sideCauses destructionTravels the slowest
59 WHAT’S the DAMAGE SEISMIC WAVES OTHER DANGERS The damage from earthquake waves depends on several factors.Intensity and duration of the vibrationsThe nature of the material on which the structure is builtThe design of the structureTsunamiThe ocean floor moves vertically along a fault.The vibration of a quake sets an underwater landslide into motion.LandslidesThe greatest damage to structures is from landslides and ground subsidence.The sinking of the ground can also be triggered by vibrations.
60 KNOWLEDGE CHECK What causes plates to move on the mantle’s surface? What force causes mountains to form?What type of boundaries are most common to find volcanoes?List 3 ways volcanoes change Earth.Where land moves and breaks is known as?Which type of Seismic Waves causes the most damage?
61 KNOWLEDGE CHECKWhat causes plates to move on the mantle’s surface? Convection currentsWhat force causes mountains to form? UpliftWhat type of boundaries are most common to find volcanoes? Convergent and DivergentList 3 ways volcanoes change Earth. Air pollution, acid rain, geysersWhere land moves and breaks is known as? FaultsWhich type of Seismic Waves causes the most damage? Surface Waves
63 ENVIRONMENTAL POLLUTION TYPES of POLLUTIONPollution is the harmful alteration of our environment by our own actions.People depend on biological diversity for the quality of their lives.Air PollutionCaused by the burning of fossil fuelsWater PollutionSewage, chemicals, etc.Land PollutionPesticides, herbicides, garbageGlobal WarmingOzone depletion
64 Threat to the Ecological Balance VEGETATIONSOILVegetation is a source of food, building material, fuel, and medicine.Destruction of vegetation:Fireclearance of vegetation, soil erosion, flooding, and wind erosionDeforestationEcosystems, nutrient cycles are affected as well as a loss of biodiversitySoil is unique in that it depends on plants and vegetation for its existence, yet plants depend on soil for their support, air, water, and nutrients.Destruction of soil:Soil compactionPrevents plant growth and encourages erosionErosion of soilIncreases flooding, landslides, and increases sediment loads leading to silting up of reservoirs
65 Threat to the Ecological Balance OCEANSLANDSCAPEThe ocean has the greatest biodiversity anywhere on the planet.Destruction of oceans and its contents:Over fishingThe depletion of fish in one area can cause the destruction of marine ecosystems.Water pollutionCaused by untreated sewage, oil, industrial chemicals, and radioactive wasteOver the past century, humans have radically altered the face of the Earth.Destruction of land:MiningPulling out natural resourcesDumping of wasteBuildingCauses loss of habitat by harvesting natural resources - Urbanization
66 Threat to the Ecological Balance AIRWATER QUALITYSources of air pollution are volcanoes, factories, and cars (both human and natural activities).Destruction of Air Quality:Greenhouse EffectWhen fossils fuels are burned, excess carbon dioxide is created resulting in the depletion of the ozone layer – Global WarmingSurface and groundwater contamination come greatly from factories, homes and farms.Destruction of Water Quality:Water ContaminationFertilizers, insecticides, and fluids from cars run off into ponds, rivers, and streams contaminating them.Some of this polluted water seeps into the ground contaminating our drinking water.
67 KNOWLEDGE CHECKWhy is it important to keep a balance between humans and their ecosystem?Identify the action with the location:Deforestation A. Water QualityFertilizers B. OceansUrbanization C. LandscapeAcid Rain D. AirIncreased Carbon Dioxide E. Vegetation
68 KNOWLEDGE CHECKWhy is it important to keep a balance between humans and their ecosystem? People depend on biological diversity for the quality of their lives.Identify the action with the location:Deforestation E A. Water QualityFertilizers A B. OceansUrbanization C C. LandscapeAcid Rain B D. AirIncreased Carbon Dioxide D E. Vegetation