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Transcript
Marine Science Unit 3 Earth Structure iceagenow.com Objectives • • • • • • • • • • • How do scientists classify the Earth’s internal layers? What is isostatic equilibrium? Explain the theory of continental drift. What are mid-ocean ridges, rift valleys, and trenches? What is the theory of sea floor spreading? What is the theory of plate tectonics Explain the difference between convergent, divergent, and transform boundaries What tools do scientists use to study ocean sediments? What are the different types of ocean sediments? Explain how sedimentation differs on the continental shelf versus the deep ocean basin. Explain marine deposition and erosion in passive vs. active coasts Layers of the Earth • • • • _________________ _________________ _________________ _________________ myschoolhouse.com The Core • Made up of __________ (90%) and nickel with some silicon, sulfur, and other heavy elements • Temperature of ____________oC (9032oF) • The total core (inner and outer together) have an estimated radius of 3470km • 31.5% of the Earth’s mass and 16% of the Earth’s volume Inner Core • Theorized to be ______ due to intense ________________ • New evidence suggests that the inner core may get as hot as 6,600oC at its center – hotter than the surface of the sun news.sciencemag.org Outer Core • Less pressure than inner core it is theorized to be a dense ______________ • Can have thermal plumes colorado.edu Mantle • Contains ________ and ____________ with some iron and magnesium • Estimated to be about 2,900km thick • Made up of the upper and lower mantle • 68% of the Earth’s mass and 83% of the Earth’s volume volcano.oregonstate.edu Mantle • Upper Mantle – Made up of _______ layers – 1. Asthenosphere (asthenes=____): The top hot layer that is partially melted slowly flowing below the lithosphere extending to a depth of 350-650km – 2. Lithosphere (lithos=______): Earth’s cool rigid outer layer that is 100-200km thick • Lower Mantle – Extends to the _________ – More ________ and _________ more slowly • Made up of the rigid solid upper portion of the mantel and the crust ksl.com Crust • Thin _______ outermost layer of the Earth • Relatively _______ temperature • 0.4% of Earth’s mass and 1% of Earth’s volume • Composed of oxygen, silicon, magnesium, and irosn • ______________ Crust – Thin and made up of mostly basalt (heavy dark colored rock) • ______________ Crust – Thicker and made up of mostly granite (light-colored rock) How does the crust float on the mantle? • _____________Equilibrium: Balance between the weight of the crust and the buoyancy provided by the mantle – As material adds to the oceanic crust or leaves the continental crust the balance becomes disrupted – Isostatic Rebound: The additional weight causes the crust to move down while the removal of material will cause the crust to move upwards – To restore ___________ landmasses rise or sink along a weak area called a fault – One theory of what causes earthquakes is when landmasses on either side of an involved fault to not move together cliffsnotes.com Buoyancy • Archimedes’ Principle of Buoyancy: An object immersed in a fluid (gas or liquid) is buoyed up by a force _________ to the weight of the fluid displaced – an object that weighs _________ than the fluid it displaces will float – If the weight of the crust changes, the landmass must ______ or ___________ to compensate Theory of Continental Drift • 1912 Alfred Wegener proposes that the continents were once a _________ landmass that drifted apart (and are still doing so) • Pangaea (pan=all; gaea=ocean) “super continent” • Pathalassa (thalassa=the sea) single large ________________ geo.tcu.edu Tectonic Jigsaw Activities 1 & 2 Compare the Pangaea you made in Activity 2 to the “real” Pangaea Evidence for Continental Drift • 1600’s - People notice the shape • Distribution of animal _____________ of continents fit together like a – Led scientists to conclude that 200 jigsaw ________________ mill yrs ago Pangaea split into to • Distribution of ______________ continents – Coal forms from remains of plants and animals in swampy climates… coal is present in antatica where there are currently no swamps • Distribution of plant __________ – 1855 Edward Suess found fossils of Glossopteris fern in South America, Africa, Australia, India, and Anartica – The seeds of this plant are too fragile to travel by sea and are too heavy to travel by wind… so, how did they get to so many different places? en.wikipedia.org • Lower - Gondwanaland • Upper-Laurasia Invention of Sonar • Detects objects under water by transmitting a __________ and receiving an __________ • SONAR is an acronym that stands for SOund _________ and Ranging • Invented around the same time that Wegener proposed the theory of continental drift and partly in response to the wreck of the _______________ • Scientists almost immediately began using sonar technology to _________ the ocean floor – German Meteor expedition mapped the contours and depths of the South Atlantic in 1925 oscilatii2011.wikispaces.com