click below
click below
Normal Size Small Size show me how
Oceanography
Chap12
Question | Answer |
---|---|
Atoll | A ring shaped island of coral reefs and coral debris enclosing, or almost enclosing, a shallow lagoon from which no land protrudes. Atolls often form over sinking, inactive volcanoes. |
Back shore | Sand on the shoreward side of the berm crest, sloping away from the ocean. |
Backwash | Water returning to the ocean from waves washing onto a beach. |
Barrier island | A long, narrow, wave-built island lying parallel to the mainland and separated from it by a lagoon or bay. |
Barrier reef | A coral reef surrounding an island or lying parallel to the shore of a continent, separated from land by a deep lagoon. Coral debris islands may form along the reef. |
Bay mouth bar | An exposed sandbar attached to a headland adjacent to a bay and extending across the mouth of the bay. |
Beach | A zone of unconsolidated ( loose) particles extending from below the water leveln to the edge of the coastal zone. |
Beach scarp | A vertical wall of variable height marking the landward limit of the most recent high tides; corresponds with the berm at high tides. |
Berm | A nearly horizontal accumulation of sediment parallel to shore;marks the normal limit of sand deposition by wave action. |
Berm crest | The top of the berm; the highest point on most beaches; corresponds to the shoreward limit of wave action during most high tides. |
Break water | An artificial structure of durable material that interrupts the progress of waves to shore. Harbors often are shielded by a breakwater. |
Coast | The zone extending from the ocean inland as far as the environment is immediately affected by marine processes. |
Coastal cell | The natural sector of a coastline in which sand input and sand outflow are balanced. |
Coral reef | A linear mass of calcium carbonate (aragonite and calcite) assembled from coral organisms, algae, mollusks, worms and so on. Coral may contribute less than half of the reef material. |
Delta | The deposit of sediments found at a river mouth, sometimes triangular in shape. |
Depositional coast | A coast in which processes that deposit sediment exceed erosive processes. |
Drumlin | A streamlined hill formed by a glacier. |
Erosion | A process of gradually being worn away. |
Erosional coast | A coast in which erosive processes exceed depositional ones. |
Estuary | A body of water partially surrounded by land where fresh water from a river mixes with ocean water, creating an area of remarkable biological productivity. |
Eustatic change | A world wide change in sea level, as distinct from local changes. |
Fjord estuary | An estuary in a fjord, a steep, submerged, U-shaped valley. |
Fjord | A deep, narrow estuary in a valley originally cut by a glacier. |
Foreshore | Sand on the seward side of the berm, sloping toward the ocean, to the low tide mark. |
Fringing reef | A reef attached to the shore of a continent or island. |
Groin | A short, artificial projection of durable material placed at a right angle to shore in an attempt to slow longshore transport of sand from a beach; usually deployed in repeating units. |
High energy coast | A coast exposed to large waves. |
Inlet | A passage giving the ocean access to enclosed lagoon, harbor, or bay. |
Lagoon | A shallow body of seawater generally isolated from the ocean by a barrier island. Also, the body of water enclosed within an atoll, or the water within a reverse estuary. |
Longshore bar | A submerged or exposed line of sand lying parallel to shore and accumulated by wave action. |
Longshore current | A current running parallel to shore in the surf zone, caused by the incomplete refraction of waves approaching the beach at an angle. |
Longshore drift | Movement of sediments parallel to shore driven by wave energy. |
Longshore trough | Submerged excavation parallel to shore adjacent to an exposed sandy exposed sandy beach; caused by the turbulence of water returning to the ocean after each wave. |
Low-energy coast | A coast only rarely exposed to large waves. |
Moraine | Hills or ridges of sediment deposited by glaciers. |
Partially mixed estuary | An estuary in which an influx of seawater occurs beneath the surface layer of fresh water flowing seaward. Mixing occurs along the junction. |
Rip current | A strong, narrow surface current that flows seaward through the surf zone and is caused by the escape of excess water that has piled up in a longshre trough. |
Salt wedge estuary | An estuary in which rapid river flow and small tidal range cause an inclined wedge of seawater to form at the mouth. |
Sand Spit | An accumulation of sand and gravel deposited down current from a headland. Sand spits often curl at their tips. |
Sea cave | A cave near sea level in a sea cliff cut by processes of marine erosion. |
Sea cliff | A cliff marking the landward limit of marine erosion on an erosional coast. |
Sea island | An island whose central core was connected to the mainland when sea level was lower. Rising ocean separates these high points from land, and sedimentary process surround them with beaches. |
Shore | The place where ocean meets land. On nautical charts, the limit of high tides. |
Swash | Water from waves washing onto a beach. |
Tombolo | Above-water bridge of sand connecting an offshore feature to the mainland. |
Wave-cut platform | The smooth, level terrace sometimes found on erosional coasts that marks the submerged limit of rapid marine erosion. |
Well-mixed estuary | An estuary in which sloe river flow and tidal turbulence mix fresh and salt water in a regular pattern through most of its length. |