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YAY only 2 Chapters Left this year! 11.1 Ocean Basins The surface of the ocean floor is as varied as the land. Basins: low points in the oceans See page 402 (c) McGraw Hill Ryerson 2007 11.1 Ocean Basins The five major oceans (from largest to smallest) the Pacific the Atlantic the Indian the Southern the Arctic See page 402 (c) McGraw Hill Ryerson 2007 11.1 Ocean Basins Oceans are vital to life: 1. they control temperature 2. create weather patterns 3. provide water for water cycles. See page 402 (c) McGraw Hill Ryerson 2007 The Origin of Ocean Water Oceans have filled over hundreds of millions of years. Scientists believe the oceans are more than 3 billion years old. See page 404 (c) McGraw Hill Ryerson 2007 The Origin of Ocean Water Water may have originally been released from volcanic eruptions, or arrived on Earth via icy comets. See page 404 (c) McGraw Hill Ryerson 2007 Features of the Ocean Floor Ocean Floors Have: Mountain ranges Valleys flat plains Canyons Volcanoes The ocean topography of the Caribbean See pages 404 - 405 (c) McGraw Hill Ryerson 2007 Features of the Ocean Floor Basin: is the large, flat middle part Continental Margins are the edges rising up to the land The ocean topography of the Caribbean See pages 404 - 405 (c) McGraw Hill Ryerson 2007 Ocean Basins Changes to the ocean basin occur: Through the movement of tectonic plates (MOST) Some erosion via storms, earthquakes and icebergs. See pages 406 - 407 (c) McGraw Hill Ryerson 2007 YOUR TURN You are going to complete the rest of your notes using your book This is good practice for grade 9!!! Ocean Basins Mid-ocean ridges occur where new rock is forced up, and ocean floor spreads outward. The Mid-Atlantic Ridge is the largest example on Earth The Juan de Fuca plate lies 200 km off Vancouver Island See pages 406 - 407 (c) McGraw Hill Ryerson 2007 Ocean Basins A trench forms when the dense oceanic plates run into, and slide under, the continental plates. See pages 406 - 407 (c) McGraw Hill Ryerson 2007 Ocean Basins (continued) Abyssal plains are the pieces of oceanic crust between a spreading mid-ocean ridge and the trench it disappears into. These make up 30% of the Atlantic sea floor, and 65% of the Pacific seafloor. Abyssal plains can be covered in 1 km of sediments See page 407 (c) McGraw Hill Ryerson 2007 Ocean Basins (continued) Seamounts are old volcanic mountains found on abyssal plains. The Hawaiian Islands are an example. See page 407 (c) McGraw Hill Ryerson 2007 Continental Margins Continental margins: are part of continental plates made up of a continental shelf (averaging 80 km wide) and a continental slope down to the oceanic plate. were above water during the last ice age. See pages 407 - 409 Take the Section 11.1 Quiz (c) McGraw Hill Ryerson 2007 Continental Margins Turbidity currents are slides on the slopes, and can create large submarine canyons in the shelf. See pages 407 - 409 Take the Section 11.1 Quiz (c) McGraw Hill Ryerson 2007 The Epipelagic Zone The upper most layer of the ocean. Enough light for photosynthesis. Base of the food chain. Majority of marine life found here. 1 to 200m. The Mesopelagic Zone Some light penetrates this layer. Insufficient for photosynthesis! Still plenty of life here. Many organisms are bioluminescent. 200 to 1000m. The Bathypelagic Zone The ocean is pitch black. No light! Some bioluminescent animals. Many animals have small eyes or no eyes at all! 1000m to 4000m. The Abyssopelagic Zone Extremely cold temperatures and high pressure. Many species in this zone are transparent and eyeless. 4000m down the ocean floor. The Hadopelagic Zone Water in the deep ocean trenches. The zone is mostly unknown. Very few species are known to live here, so a low biodiversity.