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Alfred Wegener ( Alfred Wegener (VAYG-uh-nur) Continental drift –the claim that all of the continents were once together, forming one large continent called.

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Presentation on theme: "Alfred Wegener ( Alfred Wegener (VAYG-uh-nur) Continental drift –the claim that all of the continents were once together, forming one large continent called."— Presentation transcript:

1 Alfred Wegener ( Alfred Wegener (VAYG-uh-nur) Continental drift –the claim that all of the continents were once together, forming one large continent called Pangaea. (All land) Alfred Wegener German scientist (weather man) came up with the idea

2 Continental drift-Fact or fiction? Support/ Evidence Continents seem to fit together Fossil record seems to match Rock structures match –Rock ages match Changes in climates –Glacier debris Opposition/ problems What Continental drift couldn’t answer! How can the continents move? –No mechanism to make them move –Ocean crust is to hard for the continents to move through

3 Continental Drift Possible mechanism?

4 Clicker question The term given by Alfred Wegener, which means “ all land”. a)Eurasia b)Panthalassa c)Pangaea d)Continentolossal

5 Modern Evidence Plate Tectonic theory Mid-Ocean ridges & Sea floor spreading Mid-Ocean ridge –Large under water mountain range, with a deep valley down the center –Ocean floor was moving, Why not continents? Sea floor spreading –new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge

6 Modern Evidence Plate Tectonic theory Paleomagnetism Study of Earth’s magnetic field through rocks and minerals Shown by different magnetic properties preserved in the rock record Magnetic poles reverse N  S, S  N Cause/ Mechanism Convection –Hot magma rises cool magma sinks –Causes movement within the mantle

7 What scientists discovered that there is a cycle in which the continents move. –Supercontinent cycle: continents come together and break apart –Wegener’s Pangaea

8 Breaking up “it’s not you it’s me” During the mesozoic era Pangaea began to split up. Sniff sniff so sad  –When it did it formed two separate continents named Laurasia and Gondwanaland.

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14 Clicker question How much does the Earth weigh (mass) in pounds? 13, 227,735, 700, 000, 000, 000, 000, 000 lbs.(13 octillion, 227septillion,735 sextillion 700 quintillion pounds)

15 Plate tectonics theory There are 52 tectonic plates. –14 major plates –38 minor plates So what is going on at all these plates? The theory that the earth’s lithosphere is divided into plates that move on the Asthenosphere. ASK THIS How many plates are there Mr. Hernandez?

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17 The Crust (Lithosphere) Oceanic: more dense and younger –5  10 km thick Continental: Older less dense material made from recycling of Oceanic crust –15  80km thick

18 Earth’s layers Mantle: Thickest layer; made of two parts  Lower mantle  Solid  Upper mantle/ Asthenosphere  “Putty like” and flows even though it is solid rock (very hot and under a lot of pressure) Moho- –(Mohorovic discontinuity) –Boundary that separates the mantle from the crust.  Earth quakes waves speed up.

19 Earth’s layers Lithosphere- –Crust: Oceanic Continental –Thinnest layer (5- 70km) –Even thinner when underneath the ocean. 1. 1.The wrapper –Crust 2. 2.Moho -Waxy part of wrapper 3. 3.Mantle- Shell –Upper and lower 4. 4.Core- tootsie roll –Outer liquid –Inner solid

20 How do we know? Seismic waves caused by earth quakes –Waves travel at different speeds through different mediums. (a medium is the material a wave travels through) – Primary (P) waves: Travels fast through liquid, solid, gas –Secondary (S) waves: Solids only and slower

21 Earth’s layers Moho- –(Mohorovic discontinuity) –Boundary that separates the mantle from the crust.  Earth quakes waves speed up.  Moho must be more dense

22 Lithosphere vs Asthenosphere

23 Types of plate boundaries 1.Divergent –Pulling apart –Ex. Mid-Atlantic ridge Great rift Valley Africa

24 Types of plate boundaries 3.Transform Boundary –One plate slides past another Ex. San Andreas fault –Causes earthquakes in California

25 Types of plate boundaries 2.Convergent (push) –Two plates crashing into each other Three types of plate collisions –Ocean-Continent –Ocean-Ocean –Continent--Continent

26 When will California fall off of the United States? NEVER !!!

27 Types of plate boundaries Ocean to Continental –Ocean plate is more dense subducts under continental plate. Ex. Alaska island arc

28 Types of plate boundaries –Ocean-Ocean Two oceanic plates collide Ex. –Marianas trench 1,600 miles long,43 miles wide, 36,200ft deep –Island arcs (volcanoes)

29 Types of plate boundaries 2.Continent-Continent –Two continental plates crashing into each other –Himalayan mountains. Formed by this grow an inch a year

30 Clicker question What will most likely form at a oceanic and continental plate convergence? a)Non-geologically active volcanoes b)Craters c)Hot spots d)Composite volcanoes

31 Tectonic plates Major: Pacific North American South American Eurasian African Indo-Australian Antarctican Minor: Juan de Fuca Coco's plate Nazca Caribbean

32 I.Igneous rocks are rocks that from molten material (magma/lava). A. Extrusive igneous rocks are formed when molten rock (lava) cools above ground. Usually they are formed after the material has been erupted by a volcano. 1.This molten material cools quickly. 2.No crystals are visible to the eye.

33 B.Intrusive igneous rocks are formed when molten rock cools below ground. 1.These rocks cool very slowly. 2.There is lots of time for visible crystals to grow

34 Clicker question The parent material for all rocks is: a)Quartz b)Magma c)Silica d)Granite

35 Igneous rock textures Coarse mineral grains easily visible (grains several mm in size or larger) Granite 

36 Igneous rock textures Fine mineral grains smaller than 1mm (need hand lens or microscope to see minerals)

37 Igneous rock textures Vesicular (Open spaces, bubbles)

38 Igneous rock textures Glassy Shiny no visible crystals (looks like glass)

39 Felsic VS Mafic Mineral CompositionOver all color of the rock Felsic: light in color –pink, grey, white… Mafic: Dark in color –black, brown, red… Felsic: rich in light minerals feldspar and quartz Mafic: Rich in dark minerals Magnesium and Iron (Ferric)

40 Clicker question The size and arrangement of crystalline grains in igneous rock is called a)Luster b)Hardness c)Density d)Texture

41 Intrusive rock features a) a)Batholith: Largest intrusions of rock “deep rock” b) b)Laccolith: Intrusion of rock that is parallel to the rock layers “lake of rock” c) c)Dikes: Vertical cross cutting layer of rock d) d)Sills: Parallel sheet of rock

42 Volcanoes

43 TYPES OF VOLCANOES 1.SHIELD VOLCANOES Mostly made up of lava flows Highly Mafic Ex. Hawaiian islands Hawaii

44 Shield Volcanoes Shape: Very large but gentle slopes Composition: Low silica Low gases Eruptive Style: ?

45 Types of Volcanoes 2.Cinder cone Volcano – Mostly made of cinders and other fragments Ex. Paricutin in Mexico

46 Paricutin volcano in Angahuan, Mexico was born on March 4th 1943. How do we know this? Dionisio Pulido, was plowing his field when he noticed steam coming up from the footprints of the oxen, pulling his plow. Soon, the earth shook and cracks began to form in his field. Dionisio panicked and tried to fill the steaming holes, while his wife called all the villagers to help. As you might have guessed, the volcano was born in spite of their efforts. Luckily, no one was killed. However, the village was eventually covered by lava, sparing only the front and back walls of the cathedral.

47 Cinder Cone Volcanoes Shape: Very small but steep slopes Composition: Medium silica High gases Eruptive Style: ?

48 Types of Volcanoes 3.Composite Volcanoes (stratovolcano) – Alternating layers of ash and Lava flows Steep sides – Ex. Mt. St Helens Cascade mountain range Mt. Rainier Mt. Pinatubo Mt. Fuji

49 May 17,1980

50 MAY 18, 1980

51 TODAY

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53 Clicker question Most Hawaiian island volcanoes are gently sloping and experience quieter eruptions of lava that produce basalt. Based on this description, most Hawaiian volcanoes are: A. shield cones B. cinder cones C. composite cones D. fissure eruptions

54 Composite Volcanoes Shape: Very large and steep slopes Composition: high silica high gases Eruptive Style: ?

55 Volcanoes Fissure eruption –Shape: –Flat; crack in the ground or on the ocean floor –Composition: –Low silica –Low gases –Eruptive Style: ?

56 Hot spot Volcanoes -volcanic regions They may be on, near to, or far from tectonic plate boundaries. Ex. Hawaii

57 Which Direction is the PACIFIC plate moving towards?

58 Hazards

59 Clicker question Felsic lava is usually identified by its color and its: a)silica content. b)ropy texture. c)rounded shapes. d)sulfur content.

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61 Earthquake- Sudden release of energy in the Earth’s crust, occurring at a Fault

62 Faults are breaks in the Earth’s crust –Multiple Faults are called Fault Zones

63 Three types of Faults 1.Strike slip fault –S–San Andreas 2.Normal Fault 3.Reverse Fault

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65 Earthquakes are a result of elastic rebound. –fault is locked; stress builds; rocks “bend” –When stress is too high, rocks break –Rocks rebound back to original shapes We call this THE ELASTIC REBOUND THEORY

66 Earthquakes The point at which the movement occurs or the center of an Earthquake is called its Focus. The point directly above the Focus at the Surface is known as an Earthquakes EPICENTER

67 Energy that is being released from the movement of the tectonic plates, is released IN THE FORM OF vibrations, in other words WAVES. WAVES are measured by an instrument called a seismograph –Measure vibrations of Seismic waves

68 Earthquakes have 3 types of waves –B–Body Waves --S waves –S–Surface waves

69 Body Waves –P–P-waves: Primary Waves Fastest waves, travels through both solids and liquids First to reach the seismograph Moves rock back and forth in same direction as the wave travels- compression

70 P-waves

71 Body Waves S-waves –S–Secondary Waves –C–C–C–Can only travel through solids –M–M–M–Moves rock particles side to side, at right angles

72 S-waves

73 Surface Waves Slowest moving waves –C–Cause the most damage –2–2 types of surface waves Love waves Rayleigh waves

74 Love waves –Move side to side –And perpendicular to the wave motion

75 Surface Waves Rayleigh waves –Elliptical waves –Similar to water waves

76 Locating an epicenter Difference between arrival times of P and S waves –T–T–T–This tells you the distance to the epicenter –N–N–N–Need 3 different stations to find the epicenter –T–T–T–This is called triangulation

77 Time-travel graph

78 Earthquakes Station P-Wave Arrival (hrs:min:sec) S-Wave Arrival (hrs:min:sec) S-P Lag Time (min:sec) Distance (km) Flagstaff 04:14:1504:18:45 Tucson 04:22:3004:30:00 Reno 04:18:4504:21:15

79 Earthquakes Which station A or B is closer to the epicenter of the Earthquake?

80 Earthquake Magnitude Seismic Station Epicenter Distance (km) Maximum amplitude of S-wave (mm) St. Louis, MO28050 Springfield, IL6002 Memphis, TN60500

81 Earthquake scales –R–R–R–Richter Scale – measures magnitude or energy of earthquake –1–1–1–1-10 Earthquakes are measured by two different scales.

82 Earthquake scales Mercalli Scale – – m– m– m– measures intensity of earthquake –I–I–I–Intensity = Damage caused –M–M–M–Measured with Roman Numerals –I–I–I–I – XII (1-12)

83 Earthquakes Earthquakes are measured by two different scales. –Richter Scale – measures magnitude or energy of earthquake 1-101-10


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