Coach Williams Room 310B
Marine Environment
Objectives: ◦ Explain how shoreline features are formed and modified by marine processes. ◦ Describe the major erosional and depositional shoreline features.
Headlands: land that sticks out into ocean Wave refraction: shallow water causes waves to bend Beaches: eroded headland materials Erosion causes: ◦ Cliffs, sea-stacks/arches, platforms, sea caves
Sloping band of sand, pebbles, gravel, mud at the edge of the sea Erosion & sediments ◦ Rocky coast = pebbles ◦ Volcanic rock (Hawaii) = black sand ◦ Corals/seashells = white sand
Where freshwater river/stream enters ocean Freshwater & saltwater mix
Longshore bar: sand bar Longshore current: current parallel to shore Moves sediments Rip currents: current out to sea through gap in sand bar
Erosion/sediments causes change Spits: narrow sand that sticks out in water Barrier Island: long ridges of sand apart from the mainland Lagoon: body of water behind barrier islands Tombolo: strip of sand that connects mainland and island
Artificial structures ◦ Seawalls, groins, jetties, break-waters Protect properties, beaches, etc… Causes loss of sediments on beaches
Global warming: rise ◦ Melts ice ◦ Water expands Plate tectonics ◦ Uplifts/sinking ◦ Emergent coasts: uplift of coasts
Objectives: ◦ Explain the reason for the existence of continents and ocean basins. ◦ Compare the major geologic features of continental margins and ocean basins. ◦ Describe the different types of marine sediments and their origin.
Sonar/satellite imaging Topography
Continental margin: submerged part of continent ◦ Cont. Shelf ◦ Cont. Slope ◦ Cont. Rise
Shallowest part of continental margin Average depth: 130m Was covered by water after ice age Fishing Oil, natural gas
Sloping region beyond shelf True edge of continent Turbidity currents: currents along bottom of sea. ◦ Fast moving; lots of sediment ◦ Cut canyons along slope Cont. rise: slope of deposits at base of slope
Deeper parts of ocean floor 60% of Earth’s surface Abyssal plains: smooth parts of basin Deep-Sea trenches: long depressions on basin Mid-Ocean ridges: chains of underwater mountains on ocean basin (volcanoes) Hydrothermal vents: hole in the seafloor where heated fluids erupt (magma)
Most of mountains on seafloor: extinct volcanoes Seamounts: submerged volcanoes higher than 1km Guyots: submerged volcanoes with flat tops
Most are from land Mud/sand by rivers Dust/volcanic ash by wind Ocean currents Ooze: sediments from once-living organisms Manganese nodules: sediment from valuable metals (looks like potatoes)