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Chapter 19 Section 2 Review Page 478 #’s 1-6. 1. Describe the three main sections of the continental margins. The continental shelf is the submerged part of the continent. The continental slope is the steep, seaward edge of the shelf.
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1. Describe the three main sections of the continental margins. • The continental shelf is the submerged part of the continent. • The continental slope is the steep, seaward edge of the shelf. • The continental rise is a raise wedge of sediment at the bottom of the slope.
2. Describe where the boundary between the ocean crust and the continental crust is located. • The boundary is generally offshore at the base of the continental slope.
3. Explain how turbidity currents are related to submarine canyons. • Submarine canyons may form where large amounts of sediment tumble down a slope as part of a turbidity current.
4. List four main features of the deep-ocean basins, and describe one characteristic of each feature. • Trenches: very deep, formed by subduction • Abyssal plains: vast, flat areas more than 4 km. deep and covered with a fine sediment
4. (Continued) • Mid-ocean ridges: form where plates move apart and have a narrow rift • Seamounts: submerged volcanoes that may rise above the ocean to form volcanic islands
5. Compare seamounts, guyots, and atolls. • A seamount is an underwater volcanic mountain. • Guyots and atolls form from islands. When an island sinks and the top erodes flat you get a guyot. Before the island sinks completely an atoll may form around the sinking volcano in the shallow water.
6.Explain the difference between the meanings of the terms continental margin, continental shelf, continental slope, and continental rise. • The continental margin is the name for all parts combined; • the continental shelf, continental slope, and the continental rise.