ROCKS The Mixture of Minerals

Rock VocabularyGravitational Potential EnergyUplift Composition Texture Mantle Convection Convection Currents Ridge PushSlab Pull Continental DriftPangaea Panthalassa

Rock Rock Cycle Weathering Physical Weathering Chemical Weathering Erosion Deposition Foliation Bedding

ROCKS The Mixture of MineralsChapter 3 p. 67 picture

The Rock CycleRock a naturally occurring solid mixture of crystals of one or more minerals.Rock Cycle the continual process by which new rock forms from old rock material.Rocks are always changing.

Weathering, Erosion, and DepositionWeathering the process in which water, wind, ice, and heat break down rock.Weathering is very important:Breaks down rock into fragments called sediment.The fragments are the materials that are used to make sedimentary rocks.Types of weatheringPhysical Weathering Any process in which rocks are broken down by contact with the Earths atmosphere and water.Chemical Weathering Occurs when chemical reactions break down the bonds holding the rocks together.Most common in areas that contain large amount of water.

Weathering, Erosion, and DepositionErosion the process by which sediment is removed from its source.Different types of erosion:WindIceWaterGravity

Weathering, Erosion, and DepositionDeposition the process in which sediment moved by erosion is dropped and comes to rest.Once deposited, sediments may be compressed and cemented to form a sedimentary rock.Heat and PressureHeat and pressure may cause a rock to chemical change into a metamorphic rock.If the rock gets too hot it will melt which eventually cools to form igneous rocks.

FoliationFoliation The set of layers visible in many metamorphic rocks as a result of flattening and stretching of mineral grains during metamorphism.

BeddingBedding layers of sedimentary rock.This can also be referred to as strata.Heat and PressureThe relationship of heat and pressure:^Pressure ^ Heat^ Heat ^ PressureMechanical energyGravitational Potential Energy is the potential energy associated with gravitational forces, as work is required to elevate objects against Earths gravity.How the Cycle ContinuesRock is exposed at the Earths surface by a combination of uplift and erosion.Uplift is the movement within the Earth that causes rocks inside the Earth to be moved to the Earths surface.After uplift, the rock reaches the surface, and the cycle continues.Round and Round It Goes

A Trip around the rock cycleYou are going to need your notebook for this activity.In the output section record 10 rolls of the dice. (Write down what the dice said.)You may never move from a station but continue to roll the dice at that station and write down what the dice said.Once you have finished return to your seat.Rock ClassificationThree main classes of rock:IgneousSedimentary MetamorphicIn order to identify rocks scientist break the rocks up into two categories:Composition and TextureCompositionComposition the chemical makeup of a rock; describes either the minerals or other materials in the rock.Determined by the minerals contained in the rock.Ex. A rock made of mostly the mineral quartz will have a composition very similar to that of quartz.

TextureTexture is the quality of a rock that is based on the sizes, shapes, and positions of the rocks grains.There are three different grains of texture:Fine-grainedMedium-grainedCoarse-grainedTextureThe amount of time that a igneous rock is allowed to cool determines the texture of the rock.If the rock cools quickly then it will be fine grained.If the rock cools slowly then it would be coarse grained.The texture of a rock can reveal the processes that formed it.Fine Grained Silkstone

Medium Grained Granite

Coarse Grained - conglomerate

INDIVIDUAL PRACTICE

ROGER THE ROCKYour assignment: Create a childrens story, comic strip, or some other creative story about Roger the Rock. Roger is a rock that has been a part of the rock cycle for millions of years. Your job is to tell Rogers story. You must describe how Roger was born and at least three transitions that occurred during Rogers life. (For example, changing from igneous to sedimentary, sedimentary to metamorphic, and metamorphic to igneous.) Your grade will be based on in-class work, the accuracy of your information, creativity, and neatness/effort. This should be a story appropriate for a childrens story (think back to 2nd grade here!), including pictures. To earn an A, you need to include many details-the names of specific rock types, descriptions about what causes the changes to occur, etc. This project will be due on the day of Chapter 4 Test. These projects will be presented by you and your partner.

End of Section 4.1

Mechanisms that drive lithospheric platesMantle Convection the slow creeping motion of Earths rocky mantle caused by convection currents carrying heat from the interior of the Earth to the surface.Convection Currents the uneven heating of rock in the Earths asthenosphere that causes rock to rise and sink.

Mantle Convection

Mechanisms that drive lithospheric platesRidge Push Gravitational force that causes a plate to move away from the crest of an ocean ridge, and into a subduction zone.

Gravity PullGravity Pull/Slab Pull another force where the weight of a sub-ducting slab pulls the plate at the surface down.Colder ocean plates are denser.

Wegeners Continental Drift HypothesisContinental drift the hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations.Alfred Wegener proposed the theory in the early 1900s.

Wegeners Continental Drift HypothesisSupporting EvidencePlates Fit together like a puzzle.Fossil Evidence across continents.Rocks matched across seas.Glacial striations on rocks matched on Africa and South America proving a once super continent.Coal on Antarctica proves that it was once warm.

Wegeners Continental Drift Hypothesis

Wegeners Continental Drift Hypothesis

Wegeners Continental Drift HypothesisInconclusive EvidenceNo credible evidence that explained why the continents moved.Wegner thought that the continents just plowed through the rocks.Many scientist concluded that the continents would have broken into several different pieces if this were to true.The Drifting Continents245 million years agoPangaea (Means entire Earth) existed when some of the earliest dinosaurs were roaming the Earth.Panthalassa (all sea) The ocean that once covered the Earth.

Pangaea

The Drifting Continents180 Million Years ago Pangaea gradually breaks up into two pieces.LaurasiaGondwana

The Drifting Continents65 million years ago.Dinosaurs became extinct and Laurasia and Gondwana split into two smaller pieces.

Mid-Ocean Ridges and Sea-Floor SpreadingSea-floor spreading the process in which new oceanic lithosphere forms as magma rises toward the surface and solidifies.A chain of submerged mountains runs through the center of the Atlantic Ocean.Also known as Mid-ocean Ridges

Mid-ocean ridges and Sea-Floor SpreadingAs tectonic plates move away from each other, the sea floor spreads apart and magma fills in the gap.New crust forms, older crust gets pushed away from the mid-ocean ridge.Mid-ocean Ridges and Sea-Floor Spreading

Evidence for Sea-Floor Spreading: Magnetic ReversalsBiggest evidence comes from magnetic reversals recorded in the ocean floor.North and South poles have changed places many times.Magnetic Reversal the process in which magnetic poles change places.How magnetic reversal works.Tiny grains of magnetic minerals are found at the mid-ocean ridges.Mineral grains contain iron and are like compasses.They align with the magnetic field of the Earth.When the rock cools, the record of theses tiny compasses remains in the rock.Magnetic Reversals and Sea-Floor SpreadingRock is slowly taken away from the spreading center of the ridge as sea-floor spreading occurs.

Evidence for Sea-Floor Spreading: Magnetic reversals

Seafloor SpreadingActivity on seafloor spreading.The Theory of Plate TectonicsPlate Tectonics the theory that explains how large pieces of the Earths outermost layer called tectonic plates, move and change shape.

Tectonic Plate BoundariesBoundary a place where tectonic plates touch.There are three different types of boundaries:ConvergentDivergent Transform

Convergent BoundariesConvergent Boundary the boundary formed by the collision of two lithospheric plates. There are three different types of convergent boundaries:Oceanic OceanicOceanic ContinentalContinental - ContinentalOceanic Oceanic Plate Boundarieshttp://geology.com/nsta/convergent-boundary-oceanic-oceanic.gif

Oceanic Oceanic Convergent BoundaryNormally one of the oceanic plates will subduct below the other.The older plate is usually the one that gets pushed down because it has a greater density.Eventually magma is formed because of the increased pressure causing volcanoes to form over the top of the layer.Eventually the volcanoes will peak out of the water and if they continue to grow the will form island chains.Ex. Japan

Oceanic Oceanic Plate Boundary

Continental Oceanic Plate Boundaries Mt. Adamshttp://geology.com/nsta/convergent-boundary-oceanic-continental.gif

Continental Oceanic Plate BoundariesWhen the two plates collide the less dense continental plate will rise up on top of the more dense oceanic plate.The subducted plate will become molten due to the increase in temperatures.The magma will then rise because it is less dense than the mantle that is surrounding it. As the magma rise it will cause volcanic and earthquake activity. Continental Oceanic Plate Boundaries

Continental Continental Plate Boundarieshttp://geology.com/nsta/convergent-boundary.gif

Continental Continental Convergence

Continental Continental Plate BoundariesThe process in which two land masses collide together. Normally the landmass that is the least dense will subduct only slightly below the other.Mountains will form because the two colliding plates are very light in comparison to the mantle.

Divergent Plate BoundariesDivergent Boundary the boundary between two tectonic plates that are moving away from each other.New Sea floor forms at divergent boundaries. Mid-ocean ridges is the most common type of divergent boundary.Divergent Plate Boundaries

Transform BoundariesTransform Boundary The Boundary between tectonic plates that are sliding past each other.Ex. San Andreas Fault in California. One of the few faults that can be visibly seen.One of the major causes of Earthquakes.

Output: Pushing and Pulling MountainsDraw an example of the five different plate boundaries.Label and describe what happens at each different plate boundary.Transform Plate Boundaries

Plate Summary

Possible Causes of Tectonic Plate MotionAsthenosphere flows very slowly.This movement occurs because of the change in density within the asthenosphere.Density changes because of the outward flow of energy within the Earth.Hot rock expands and rises.(Less Dense)Cool rock contracts and sinks. (More Dense)Possible Causes of Tectonic Plate Motion

Tracking Tectonic Plate MotionTectonic plates move roughly 5cm per year.The rate is so slow that it cannot be seen nor felt except during an Earthquake.Plate movement is tracked by GPS.

Fall ZoneThe fall zone marks the geologic boundary of hard metamorphosed terrain and the sandy, relatively flat outwash plain of the upper continental shelf.The transition from the harder metamorphosed rock to the softer sediment creates water falls.Formed from the erosion of the mountain regions of NC to help form the Sandy coastal plain regions.

lithospheric platestectonic platedivergentconvergenttransformseafloor spreadingmantleconvectionridge pushslab pullmid-ocean ridgerift valleytrenchsubduction zonetheory of plate tectonicsmagnitudelaharpyroclastic flowP-waveS-wavemagnitudeepicenterfocal pointRing of fire

Volcanic EruptionsVolcanoes are areas of Earths surface through which magma and volcanic gases pass.Explosion of a volcanic eruption can turn an entire mountain into a billowing cloud of ash and rock in a matter of seconds causing global climate temperatures to drop.Help form fertile land.Create some of the largest mountains on earth.Volcanic EruptionsMagma melted rock below the Earths surface.Lava Melted rock above the Earths surface.Mt. Cleveland- Aleutian Islands, Alaska

Stromboli Volcano - Sicily

Mount Redoubt - Alaska

Types of Lava FlowsPahoehoe lava flows sheet like lava flows that result in continuous surfaces.Flow smoothly Move forwards in tongues or lobes and are characterized by a glassy, plastic skin.Pahoehoe Lava Flow

Types of Lava FlowsAa lava pours out quickly and forms a brittle crust.The crust is torn into jagged pieces as molten lava continues to flow underneath.Got its name because of the painful experience of walking barefoot across the jagged surfaces.Associated with lava fountaining. Aa Lava Flow

Lava FountainingLava Fountaining spraying of lava into the air pulsing with the pressure of escaping gases.

Types of Lava FlowsPillow lava forms when lava erupts underwater.Lava forms rounded lumps that are the shape of pillows.

What erupts from a Volcano?Lava liquid magma that flows from a volcanic vent.Pyroclastic material - forms when magma is blasted into the air and hardens.Nonexplosive eruptions produce mostly lava.Explosive eruptions produce mostly pyroclastic material.Volcanos eruptions may alternate between lava and pyroclastic eruptions.Pyroclastic MaterialVolcanic BombsVolcanic Bombs large blobs of magma that harden in the air. The shape of the bomb was caused by the magma spinning through the air as it cooled.

LapilliLapilli pebblelike bits of magma that hardened before they hit the ground.Means little stones

Volcanic AshVolcanic Ash forms when the gases in stiff magma expand rapidly and the walls of the gas bubbles explode into tiny, glasslike slivers.Makes up most of the pyroclastic material in an eruption.Volcanic Ash

Pyroclastic FlowsPyroclastic Flow produced when enormous amounts of hot ash, dust, and gases are ejected from a volcano.Can move downhill at 200km/h.Center of the flow can exceed 700 C.

End of Section 9.1

88Effects of Volcanic EruptionsJune 10, 1816 ConnecticutDear Diary, The clothes my wife had laid out to dry the day before had frozen during the night.Volcanic Eruptions and Climate Change1815, Mount Tambora blanketed most of Indonesia in darkness for more than 3 days.12,000 people died directly from the explosion.80,000 people died from the resulting hunger and disease.

Volcano TypesWatch the video and write down the types of volcanoes and characteristics associated with them.Mauna Kea - Shield Volcano

Cinder Cone Volcanoes

Mt. St. Helens

Mt. St Helens 1980 Deadly

Mt. Fuji

CratersCrater funnel-shaped pit found around the central vent at the top of many volcanoes.When eruption stops, lava drains back underground making a larger collapsed crater.Next eruption may blast it away creating a larger and deeper crater.Kamchatka, Russia

CalderasCaldera a large, semicircular depression that forms when the magma chamber below a volcano partially empties and causes the ground above to sink.Much larger than a crater.

Crater Lake, Washington

Lava PlateausLava Plateau a wide, flat landform that results from repeated nonexplosive eruptions of lava that spread over a larger area.Formed from seepage of magma from long cracks or rifts.Lava can pour out for millions of years and spread over huge areas.

Lahar (mud) FlowsA type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris, and water.Typically occurs along a river.Has the density and consistancy of concrete.Possible Causes of a LaharMelted glaciersMixture with wet soil to create a viscous material.Water from a crater lake.

Columbia River Plateau

End of Section 9.2

Where Volcanoes FormMost volcanoes are found directly on tectonic plate boundaries.80% of active volcanoes on land form where plates collide.15% form where plates separate.Other rare and few volcanoes form far away from plate boundaries known as hotspots.Ring of FireThe location of the worlds most active volcanoes. The ring is entirely located along plate boundaries in which many earthquakes occur as well.

HotspotsHotspot is a location on the Earths surface that has experienced active volcanism for a long period of time. Often located in the middle of oceanic plates.Hawaii is an example of an active hotspot.When Tectonic Plates SeparateRift zone an area of deep cracks that forms between tectonic plates that are pulling away from each other.Mantle rock lifts up to fill the gap.As mantle rises the pressure decreases allowing the rock to melt and form magma.

EarthquakesSafety Game

What Are Earthquakes?Seismology the study of earthquakes.Seismologist scientist who study Earthquakes.Earthquake the shaking of the Earths surface due to the movement of tectonic plates.

Where Do Earthquakes Occur?Most if not close to all Earthquakes occur near the edges of tectonic plates.Due to the movement of tectonic plates, numerous features called faults exist in the Earths crust.Fault is a break in the Earths crust along which blocks of the crust slide relative to one another.Where Do Earthquakes Occur?

What Causes Earthquakes?Deformation the bending, tilting, and breaking of the Earths crust; the change in the shape of rock in response to stress.This process occurs in two ways:Plastic deformation.Elastic deformation.P.220Stress p.3094 FaultsNormalReverseThrust FaultStrike SlipP. 315 Draw and LabelPlastic DeformationPlastic Deformation a rock that deforms in a stretching gentle manner.Example: Pulling apart a piece of molded clay.

Elastic DeformationElastic Deformation rock is stretched until it can no longer stand the force in which the rock springs back to its original location.Rock can stretch farther than steel without breaking.Example: Stretched rubber band.

Elastic ReboundElastic Rebound the sudden return of elastically deformed rock to its undeformed shape.Occurs when more stress is applied to the rock than the rock can stand.Energy is released during the rebound.Energy is released as seismic waves.Visualizing Elastic Reboundhttp://projects.crustal.ucsb.edu/understanding/elastic/rebound.html

How Do Earthquake Waves Travel?Seismic Wave a wave of energy that travels through the Earth, away from an earthquake in all directions.Body Waves seismic waves that travel through the Earths interior.Surface waves seismic waves that travel along the Earths surface. Types of Waves (Not earthquake waves but pretty cool)P-waves or Primary Waves Types of seismic waves that move in a compression manner.Ex. A slinky moving back and forth from end to end.Has the ability to move through all materials.Fastest moving wave.Types of WavesP-waves are always the first waves of an earthquake to be detected.

Types of WavesS-Waves or Secondary waves are waves that move up and down.Ex. Stretching a slinky outward and then pulling down on the center so that it would bounce up and down. Cannot move through a liquid.Waves are very damaging to surface objects.Types of WavesS-waves are also known as shear waves because of the damage they cause to the Earths rocks at the surface.S-waves cannot travel through parts of the Earth that are completely liquid. S-waves are slower than P-waves and always arrive later than P-waves.Surface WavesSurface Waves are waves that move along the Earths surface and produce motion mostly in the upper few kilometers of Earths crust.Two types:Rayleigh Wave - Produces up, down, and around motion.Love Waves - Back and forth motion much like S-waves.These waves are more destructive than body waves and move more slowlySurface Waves

Locating EarthquakesSeismographs instruments located at or near the surface of the Earth that record seismic waves.

Seismogram tracing of earthquake motion recorded by a seismograph.

Determining Time and Location of EarthquakesSeismologists find an earthquakes start time by comparing the differences in arrival times of P waves and S waves.

Determining Time and Location of EarthquakesEpicenter the point on the Earths surface directly above an earthquakes starting pointFocus the point inside the Earth where an earthquake begins.

The S-P Time MethodS-P time method the way in which seismologists find an earthquakes epicenter.Collect several seismograms of the same earthquake from different locations.Seismograms are placed on a time-distance graph.By reading the horizontal axis the distance from the earthquake can be determined.The S-P Time Method

The Richter Magnitude ScaleRichter scale a scale used to measure the strength of an earthquake.

Earthquake Ground MotionMagnitude the strength of an earthquake.Every time that the Richter scale increases by one it will produce 10x as much ground motion.Ex. 5 on the scale will be 10x stronger than an earthquake that is a 4.

Modified Mercalli Intensity ScaleIntensity a measure of how much damage caused by the earthquake.The Scale uses roman numerals I-XIIShows the type of damage caused by an earthquake.

Strength and FrequencyEarthquakes vary in strength.Earthquakes dont occur on a set schedule.But, the strength of an earthquake is related to how often they occur.Strength and Frequency

The Gap HypothesisGap hypothesis a hypothesis that states that sections of active faults that have had relatively few earthquakes are likely to be the sites of strong earthquakes in the future.Seismic Gap areas along a fault where relatively few earthquakes have occurred.Volcano Earthquakehttp://www.iknowthat.com/mhscience/Earthquakes/Fixed.htmMega disasterJapanese SimulatorSome Notable Earthquakes

143Seismic VibrationsDestruction The damage to buildings and other structures from earthquake waves depends on several factors. These factors include the intensity and duration of the vibrations, the nature of the material on which the structure is built, and the design of the structure.Earthquake Damage

145Seismic VibrationsDestruction Building Design- The design of the structure- Unreinforced stone or brick buildings are the most serious safety threats- Nature of the material upon which the structure rests Factors that determine structural damage- Intensity of the earthquake

Seismic VibrationsDestruction Liquefaction Saturated material turns fluid Underground objects may float to surface Effects of Subsidence Due to Liquefaction

149TsunamisDestruction Cause of Tsunamis A tsunami triggered by an earthquake occurs where a slab of the ocean floor is displaced vertically along a fault. A tsunami also can occur when the vibration of a quake sets an underwater landslide into motion. Tsunami is the Japanese word for seismic sea wave.Movement of a Tsunami

151TsunamisDestruction Large earthquakes are reported to Hawaii from Pacific seismic stations. Tsunami Warning System Although tsunamis travel quickly, there is sufficient time to evacuate all but the area closest to the epicenter.Other DangersDestruction With many earthquakes, the greatest damage to structures is from landslides and ground subsidence, or the sinking of the ground triggered by vibrations. Landslides In the San Francisco earthquake of 1906, most of the destruction was caused by fires that started when gas and electrical lines were cut. FireLandslide Damage

154Predicting EarthquakesDestruction So far, methods for short-range predictions of earthquakes have not been successful. Short-Range Predictions Scientists dont yet understand enough about how and where earthquakes will occur to make accurate long-term predictions. Long-Range Forecasts A seismic gap is an area along a fault where there has not been any earthquake activity for a long period of time.Seismic Waves Paths Through the Earth

156Earths Layered Structure

157Discovering Earths Layers8.4 Earths Layered Structure Velocity of seismic waves increases abruptly below 50 km of depth Separates crust from underlying mantle Shadow Zone Absence of P waves from about 105 degrees to 140 degrees around the globe from an earthquake Can be explained if Earth contains a core composed of materials unlike the overlying mantle MohoEarths Interior Showing P and S Wave Paths

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