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Transcript
Warm Up 2/4 1. What is the biggest difference between an ROV and an AUV? 2. Name the ROV that explored the Titanic. 3. Name the HOV that explored hydrothermal vents. 4. Name the bathyscaphe that traveled to the Mariana Trench 5. What is one piece of information a scientist could gather from an ocean corer? 1 James Cameron Challenger Deep 43” diameter of internal cabin!!! 70 minute ascent! 2 Ocean Geography Earth is 71% water Is that water evenly distributed over the earth? Northern Hemisphere Southern Hemisphere Nope! 61% ocean 80% ocean 4 Water, water, every where, Nor any drop to drink. 5 6 Ocean Geography There are ____________ large ocean basins. 1. 2. 3. 4. Are these oceans separate? “World Ocean” = term used by oceanographers 7 SIZE (in millions of km2) DEPTH (feet … average) TEMPS PACIFIC 166.2 13,741 Depends on location ATLANTIC 86.5 12,258 Depends on location INDIAN 73.4 3,872 Hottest ARCTIC 9.5 1,330 Coldest 8 9 10 Ocean Diagrams in Notes Label, color code, cut and paste into notes 11 Ocean Geography 12 Ocean Geography What’s the difference between an ocean and a sea? 13 Structure of the Earth Big Bang explosion 4.5 billion years ago Cosmic dust particles collide Condensed to a molten earth Denser particles flowed to center D = mass volume Formation of Earth 14 Figure 2.03 Layers of the earth cake 15 Earth’s Layers Model Materials: Earth’s Layers handout Scissors Colored pencils Glue sticks textbook Procedure: Fill in blocks of 4 main layers of earth on lower right side Cut and paste blocks next to corresponding wedge Cut and label portions of earth’s interior (terms on left side) Use textbook as guides 16 Earth’s Layers Model 17 Layers of the Earth 18 Layers of the Earth Core Inner Core – solid Outer Core – liquid Mantle Thought to be solid, but so hot that it flows like lava Swirls and mixes like boiling soup = convection currents 19 Layers of the Earth Mantle (continued) Asthenosphere Portion of upper mantle Location of convection Lithosphere Upper mantle into the crust Where plates located 20 mantle convection 21 Layers of the Earth Crust Thin in comparison to core and mantle Ex) Gravy skin Rigid skin on top of mantle Two kinds Banana pudding Continental Oceanic Crust and Mantle - Wiz 22 Structure of the Earth OCEANIC CRUST Basalt 5km “thin” “young” Dark in color Iron, magnesium =DENSE CONTINENTAL CRUST Granite 20-50km thick “old” Light in color Sodium, potassium, calcium, aluminum 23 Continental Drift Theory Alfred Wegener 1912 Supercontinent Pangaea What is up with these drifting continents, y’all? 24 Continental Drift Theory Similarities in: 1. types of fossils (Mesosaurus) 2. shape and fit of continents and rock formations; 3. age and structure 25 Evidence of continental drift 26 Wegener’s proposed ‘Pangaea Puzzle’ 27 I know the plates are moving. I just don’t know how to prove it… 28 Plate Tectonics Theory 1950s Entire surface of earth moves, not just continents Lithosphere crust and uppermost mantle Plates- broken up pieces that move over the more “plastic” (fluid) asthenosphere REVIEW: What’s the asthenosphere famous for??? CONVECTION CURRENTS!! 29 What crazy awesome technology developed during WW2 helped to validate the Theory of Plate Tectonics?????? 30 SONAR 31 Mid-Ocean Ridge discovered by sonar after WWII chain of submarine volcanic mountains Largest geological feature on the earth. Displaced from side to side by transform faults (cracks) Mid-Atlantic Ridge East Pacific Rise 32 Mid-ocean ridges, trenches, and transform faults 33 Portion of the midAtlantic ridge in Iceland 34 Sea Floor Spreading (cont’d) Sonar also found trenches, mostly in the Pacific Tons of geological activity along mid ocean ridges. Earthquakes- near ridges Volcanic activity- near trenches 35 http://www.geosociety.org/educate/LessonPlans/SeaFl oorSpreading.pdf 37 Distribution of earthquakes and volcanoes associated with plate boundaries 38 Significance of Mid-ocean ridges Geologic ages- rocks near the ridge are “young” compared to rocks far from the ridge Very little sediment near the ridge- and an increase in sediment further from the ridge Magnetic anomaly bands Bands of rock on seafloor parallel to mid-ocean ridges Alternate between normal and reversed magnetization Mirror images on opposite sides of ridge 39 40 41 42 Warm up 9/10 Answer the following in complete sentences: In what state of matter does the inner core exist? What ocean has the greatest average depth? What hemisphere contains the greatest percentage of ocean water? What term from yesterday’s earth picture does this diagram represent? 43 Warm up 9/11 1. Identify and describe two differences in characteristics of rock near a mid-ocean ridge as opposed to further from the ridge. 2. Describe two of the three pieces of evidence that supported Wegener’s Continental Drift Theory. 3. What do the black and white stripes on the diagram below represent? 44 Agenda 9/11 Finish seafloor spreading lab Resume notes Tsunami videos, article, questions 45 46 47 Magnetic anomaly bands prove seafloor not created all at once but cooled from molten material at different times in geologic history 48 Creation of the Sea Floor Pieces of oceanic crust separating at mid-ocean ridges create cracks called rifts Rifts release pressure (remove cap from soda bottle) Allow molten material (bottled up) to reach earth’s surface, cool, solidify and form new crust 49 Creation of the Sea Floor Seafloor spreading = process by which the sea floor moves away from the mid-ocean ridge to create new sea floor Occurs at a divergent boundary (moving away) Bill Nye Seafloor 50 MID-OCEAN RIDGE Seafloor spreading Divergent (plates separate, magma bubbles up) TRENCH Subduction Convergent (plates move together, form trench) Earthquakes = tsunamis 51 Seafloor Spreading and Plate Tectonics… REVIEW: Plates (in lithosphere) float on swirling convection of asthenosphere New oceanic lithosphere (plates) formed at mid-ocean ridges If that plate also includes a slab of continental plate, then continents move too As new is created, old is destroyed. WHY? 52 Seafloor Spreading and Plate Tectonics… Lithosphere destroyed at trenches Formed when 2 plates collide and 1 dips below the other and sinks into mantle https://www.youtube.com/watch?v=ryrXAGY1dmE 53 Seafloor Spreading and Plate Tectonics… Subduction = downward movement of plates Trenches are AKA “subduction zones” because this is where subduction occurs! Convergent boundaries (moving together) Island arcs = volcanic island chains associated with trenches 54 55 Subduction of oceanic and continental plates Subduction of two continental plates Why will the oceanic plate sink under the continental plate every time????? 56 Earth’s major lithospheric plates 57 Tsunamis series of great sea waves caused by an underwater earthquake, landslide, or volcanic eruption. 58 Tsunamis Indonesian - History Channel Japanese Tsunami 2011 Banda Aceh Tsunami 59 60 Warm up 9/12 Ridges and Trenches!! 1. In a complete sentence, compare and contrast ridges and trenches by the plate boundary at which they occur 2. Name the 2 major ridges of the Pacific and Atlantic Oceans 3. At which geologic feature is seafloor created? 4. At which trench is seafloor destroyed? 61 Agenda 9/12 Finish tsunami work worth a test grade now Finish notes 12 slides (only 8 with words) Sketch, label, submit designs with group members (3-4 in each) After school tutoring FRIDAY = models, lab questions 62 Tohoku Tsunami Tsunami crashing 1:30 in 63 Fukushima 64 65 Geologic Records in Ocean Sediments Studying sediments gives clues to the history of the earth Two major types: 1. Lithogenous- derived from terrestrial rock that has been eroded- most common is red clay 66 Geologic Records in Ocean Sediments 2. Biogenous- made of skeletons and shells of marine organisms Calcareous ooze- primarily CaCO3, calcium carbonate Siliceous ooze- primarily SiO2, or silica. These microfossils can give clues to ancient ocean temperatures 67 Geological Provinces of the Ocean Seafloor divided into 2 main regions 1. Continental margins = submerged edges of continents 2. Deep-sea floor Continental margin 68 Continental Margin Boundaries between continental and oceanic crusts Where thick sediment deposits Up to 6 miles of sediment deep! Made of 3 parts: 1. Continental shelf- biologically rich, part of continent that is underwater. Ends at a ‘shelf break’ where shelf abruptly gets steeper 69 Continental margin (cont’d) 2. Continental slope- begins at shelf break and descends to deep-sea floor 3. Continental rise- made of thick layers of sediments building up on sea floor at the base of the slope. 70 The Continental Margin 71 72 Deep Ocean Basins Abyssal Plain Great plain on ocean floor - very flat Covers 50% of earth’s surface Can be interrupted by seamounts (underwater mountains), or guyots (flat topped seamounts) Habitat of unusual marine organisms 73 74 75 76 Warm up 9/13 The tsunamis in Indonesia and Japan in 2004 and 2011 were a result of earthquakes at what type of plate boundary? 2. What geological feature occurs at this type of boundary? 3. Describe the components that make up biogenous sediment. How are these different than components of lithogenous sediment? 4. Which part of the continental margin is the steepest and occurs after the shelf break? 1. 77 Warm Up 9/16 In a complete sentence, describe the differences between passive and active margins. Would point A fall on a passive margin? Why or why not? 78 Warm Up 9/16 Label the features represented at points A,B,C, and D A D Which of the four features represented at A,B,C, and D accounts for the majority of the sea floor (and thus, earth’s surface)? What is the difference between a guyot and a seamount? 79 Agenda 9/16 Finish models Finish lab questions Get your grade from me Vocabulary homework Notes/Pictures/Video on Hydrothermal vents Possibly start new material 80 After school Review Today 2:20pm Meet here, possibly move rooms Going through the test by concept 81 How big is the blob fish?? 82 83 84 Continental Margins Two Types 1. Active margins- occur at plate boundaries Geologically very active- earthquakes and volcanoes trenches found offshore, no rise shelf is nearly non-existent, slope is very steep often have steep rocky shorelines Ex- West coast of South America 85 Two types of Continental Margins (cont’d) 2. Passive margin- edge of continental crust is within a plate- no plate boundary nearby Geologically ‘inactive’ flat coastal plains wide continental shelves, more gradual slopes, thick rises Ex- North Carolina! 86 87 Oceanic and continental crust meet at plate boundary = ACTIVE Oceanic and continental crust meet within a plate = PASSIVE 88 Multibeam sonar image of the continental shelf off the coast of Atlantic City, NJ 89 Multibeam sonar image of the coast of California 90 91 Degrees West Longitude 70.0 70.2 70.4 70.6 70.8 71.0 71.2 71.4 71.6 71.8 72.0 72.2 72.4 72.6 72.8 73.0 Elevation (m) 1945 2327 1193 -800 -1661 -3463 -4888 -7132 -5430 -4526 -3985 -4117 -4105 -4293 -3582 -4022 92 Figure 2.20 93 Mid-ocean ridges and hydrothermal vents Separation at mid-ocean ridges creates cracks called rifts Seawater seeps in the cracks and is heated by rising magma Hot water rises through the crust as hydrothermal vents (deep sea hot springs) Nat Geo hydrothermal vents Up to 600 degrees!! 94 Figure 2.23 95 Hydrothermal Vents Lava bursting forth, bringing with it hydrogen sulfide, or H2S, which is poisonous to living things on earth!!! These living species not only survive in it, but they thrive. And they do it in total darkness!!!! H2S skin rash (mild contact) 96 Hydrothermal vents Mineral rich water cools in the ocean and the minerals are deposited, making tall chimneys called black or white smokers Rich in unusual marine life!!!!! Hydrothermal vent creatures 97 Hydrothermal vents So why are scientists so surprised to find life so deep in the ocean? What did they previously think organisms needed to survive? 98 Figure 2.24 99 Figure 2.25 100 Organisms of Hydrothermal Vent Communities Tube worms have no mouth, eyes or stomachs- they have bacteria inside them that produce their food. 101 Yeti Crab!!!!!!!!!!!! 102 Vent crabs are predators in hydrothermal vent communities… 103 But the top dog is the Vent Octopus Many animals at this depth lack color or pattern. Why???? In the dark, there’s no need to camouflage for hunting or hiding! 104 Seafloor geology and life. What is the connection between the geological features of the seafloor and living things in the ocean?? 105 35 multiple choice 10 fill-in blank (6 diagram) 2 short answers Test Information Four layers of earth Plate boundaries Four major ocean basins Oceanic vs. continental crusts Wegner, Continental Drift Theory, Plate Tectonics Review from first two quizzes [4 questions] Mid-ocean ridges [MidAtlantic, East Pacific Rise, rifts] [Convergent vs. divergent] Processes [seafloor spreading vs. subduction] Geological features [midocean ridge vs. trench] Tsunamis and cause Sediments Continental margin, abyssal plain Hydrothermal vents 106 Diagram on Test 107