* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download The Seafloor Lesson 4
Survey
Document related concepts
Geochemistry wikipedia , lookup
Deep sea community wikipedia , lookup
Hotspot Ecosystem Research and Man's Impact On European Seas wikipedia , lookup
Anoxic event wikipedia , lookup
Plate tectonics wikipedia , lookup
Oceanic trench wikipedia , lookup
Arctic Ocean wikipedia , lookup
Marine pollution wikipedia , lookup
Marine biology wikipedia , lookup
Ocean acidification wikipedia , lookup
Abyssal plain wikipedia , lookup
Transcript
The Seafloor •UNIT 8 •STANDARDS: NCES 2.1.1, 2.1.4, 2.3.1, 2.6.4 •LESSON 4 Lesson Objectives • In this lesson, you will learn about: – – – – The reason for continents and ocean basins The major features of continental margins The major features of ocean basins The different types of marine sediment and their origins Oceanic and Continental Crust • General Ocean • High mountains and deep topography • • • Continental Margins • • depressions (trenches) The deepest point is the Marianas Trench in the Pacific Ocean Continental and Oceanic are the two types of the crust The submerged parts of the continents. Shallowest part of oceans Continental Shelf • The continental margins are the areas where the edge of the continents meet the ocean. • The shallowest part is the continental shelf and extends to slope down to the continental rise and eventually the ocean floor. • The continental shelves are of great economic importance. First of all, about 90% of the world’s supply of seafood comes from here. Second, valuable oil deposits can be found in some shelf areas. Continental Slopes • Continental Slope • Turbidity Current • Continental Rise • Beyond the continental shelf, the seafloor drops off quickly. These regions are continental slopes. • Cut the underwater canyons. They are rapidly flowing water on the seafloor carrying heavy loads of sediments. • The deposited sediments by the turbidity currents and rest on the seafloor. They will build the continental rise. Ocean Basins • Abyssal Plains: Smooth parts of the ocean • Ocean Basin Features floor covered in hundreds of meters of mud. • Deep-Sea Trenches: cut by turbidity currents and are the deepest parts of the ocean. Often lie near subduction zones. Marianas Trench, deepest part on the globe. • Mid-Ocean Ridges: Underwater mountains formed by new oceanic crust . • Hydrothermal Vents: Holes on the seafloor where fluids heated by the hot magma erupts. Black smokers are the most common. Marine Sediments • Source • Sediments cover the ocean floor. Smoothest, flattest part of the earth is the abyssal plain where sediment is hundreds of meters thick and undisturbed. • Sediments originate on the continents and are washed into the oceans. • Deep Sea OOZE • Formation • Formed by the shells and body parts of marine organisms. When the organism dies, its remains rain down onto the ocean floor. VERY slow to dissolve. • Generally accumulate at a rate of millimeters per thousands of years. Manganese Nodules • What are they? • Nodules (packets similar in size to a potato) that contain manganese, iron, copper, and other valuable metals. • How do they form? • The metals are precipitated directly from the seawater and collect in these nodules. EXTREMELY SLOW growth, millimeters per millions of years. Marianas Trench • The deepest part of the ocean. • The deepest point below sea level on the planet. • Watch the video of the exploration of the trench. History Channel: Marianas Trench NatGeo Video Clips • • • • • Drain the Ocean (Part 1 of 5) Drain the Water Drain the Ocean (Part 2 of 5) Organisms Drain the Ocean (Part 3 of 5) Plate Movement Drain the Ocean (Part 4 of 5) Tallest Mountains Drain the Ocean (Part 5 of 5) Massive Structures Ocean Landscape Summary Section Review 8.4.1 • How are submarine canyons formed? • Which sediments do you think sink faster, pebbles or sand grains? • Arrange the following sediments from CLOSEST to land to DEPEST Ocean: Pebbles, silt, sand, clays, animal shells. • Why are companies investigating harvesting manganese nodules?