Geology 101 Oceans Study Guide
Chapter 15 – Restless Realm: Oceans and Coasts
Key Point • Why does ocean water circulate? • How does the topography of the ocean floor change from a continental margin to the mid-ocean ridge? How are the oceans mapped? • How do ocean waves and breakers form? • How sediments are moved along a shore line and what coastal features are formed? • Be able to recognize both depositional and erosional coastal landforms
Why should we study the oceans? • 70% of Earth’s surface • Source for food, energy • Used for transportation • Drives Hydrologic Cycle • In 1990, 50% of the U.S. population lived within 75 km of a coast; and by 2010, 75% will.
Ocean Water
Composition
• Salinity is the concentration of salt in seawater (approximately 3.5%) • The dissolved salt content is not constant and changes with location and depth, the more evaportation the higher the concentration
Temperature is stratified - varies with depth
Ocean Currents
Ocean currents move large amounts of water and heat by: - wind-driven surface ocean circulation - density-driven deep-ocean circulation Cold salty water tends to sink Warm, less salty water rises
Both redistribute heat from warmer regions to cooler regions
Landscapes Beneath the Sea
Mapping the seafloor by: • Satellite measurements • Echo sounding profiles • Side-scan sonar • Manned and unmanned submersibles
[pic]
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Major Physiographic Features in the Atlantic Ocean • continental margin – continental shelf – A broad, flat platform extending from the shoreline to the beginning of the continental slope. – continental slope - A steeper (~4º) , typically mud-draped slope marking the edge of the continental shelf. Dissected by submarine canyons and modified by turbidity currents – continental rise - A gently sloping apron of sediment formed by
Key Point • Why does ocean water circulate? • How does the topography of the ocean floor change from a continental margin to the mid-ocean ridge? How are the oceans mapped? • How do ocean waves and breakers form? • How sediments are moved along a shore line and what coastal features are formed? • Be able to recognize both depositional and erosional coastal landforms
Why should we study the oceans? • 70% of Earth’s surface • Source for food, energy • Used for transportation • Drives Hydrologic Cycle • In 1990, 50% of the U.S. population lived within 75 km of a coast; and by 2010, 75% will.
Ocean Water
Composition
• Salinity is the concentration of salt in seawater (approximately 3.5%) • The dissolved salt content is not constant and changes with location and depth, the more evaportation the higher the concentration
Temperature is stratified - varies with depth
Ocean Currents
Ocean currents move large amounts of water and heat by: - wind-driven surface ocean circulation - density-driven deep-ocean circulation Cold salty water tends to sink Warm, less salty water rises
Both redistribute heat from warmer regions to cooler regions
Landscapes Beneath the Sea
Mapping the seafloor by: • Satellite measurements • Echo sounding profiles • Side-scan sonar • Manned and unmanned submersibles
[pic]
[pic]
Major Physiographic Features in the Atlantic Ocean • continental margin – continental shelf – A broad, flat platform extending from the shoreline to the beginning of the continental slope. – continental slope - A steeper (~4º) , typically mud-draped slope marking the edge of the continental shelf. Dissected by submarine canyons and modified by turbidity currents – continental rise - A gently sloping apron of sediment formed by