Oceanography Chapter 12
Terms
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- Above-water bridge of sand connecting an offshore feature to the mainland
- Tombolo
- 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.
- Barrier Reef
- An accumulation of sand and gravel deposited down current from a headland. Sand spits often have a curl at the tips.
- Sand Split
- A long, narrow, wave-built island lying parallel to the mainland and separated from it by a lagoon or bay. Compare sea island.
- Barrier island
- The top of the berm; the highest point on most beaches. Corresponds to the shoreward limit of wave action during most high tides.
- Berm Crest
- An exposed sand bar attached to a headland adjacent to a bay and extending across the mouth of the bay
- Bay Mouth Bar
- A coast only rarely exposed to large waves.
- Low-energy Coast
- Water returning to the ocean from waves washing onto a beach.
- Backwash
- 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
- Lagoon
- A zone of unconsolidated (loose) particles extending from below water level to the edge of the coastal zone.
- Beach
- An estuary in which rapid river flow and small tidal range cause an inclined wedge of seawater to form at the mouth.
- Salt Wedge Estuary
- A ring-shaped island of coral reefs and coral debris enclosing, or almost enclosing shallow lagoon from which no land protrudes. Atolls often form over sinking, inactive volcanoes
- Atoll
- Coasts on which terrestrial influences dominate. See also secondary coast.
- Primary Coast
- Sand on the shoreward side of the berm crest, sloping away from the ocean
- Backshore
- An estuary along a coast in which salinity increases from the ocean to the estuary's upper reaches because of evaporation of seawater and a lack of freshwater input.
- Reverse Estuary
- An estuary in which an influx of seawater occurs beneath a surface layer of fresh water flowing seaward. Mixing occurs along the junction
- Partially mixed estuary
- A cave near sea level in a sea cliff cut by processes of marine erosion
- Sea Cave
- A nearly horizontal accumulation of sediment parallel to shore. Marks the normal limit of sand deposition by wave action.
- Berm
- Cliff marking the landward limit of marine erosion on an erosional coast.
- Sea Cliff
- The deposit of sediments found at a river mouth, sometimes triangular in shape (hence the name after the Greek letter).
- Delta
- A hill and/or ridge of sediment left from the ice ages when the glaciers retreated. Some examples include: New York, and Cape Cod, Massachusetts
- Moraine
- Submerged excavation parallel to shore adjacent to an exposed sandy beach. Caused by the turbulence of water returning to the ocean after each wave
- Longshore Trough
- A submerged or exposed line of sand lying parallel to shore and accumulated by wave action
- Longshore Bar
- Coasts dominated by marine processes. See also primary coast
- Secondary Coast
- The place where ocean meets land. On nautical charts, the limit of high tides.
- Shore
- 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
- Estuary
- Island whose central core was connected to the mainland when sea level was lower. Rising ocean separates these high points from land, and sedimentary processes surround them with beaches. Compare barrier island.
- Sea Island
- An estuary in which slow river flow and tidal turbulence mix fresh and salt water in a regular pattern through most of its length.
- Well-mixed Estuary
- 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
- Groin
- The dissolving by water of minerals in rocks
- Dissolution
- The smooth, level terrace sometimes found on erosional coasts that marks the submerged limit of rapid marine erosion
- Wave-cut Platform
- Vertical wall of variable height marking the landward limit of the most recent high tides. Corresponds with the berm at extreme high tides.
- Beach Scarp
- An artificial structure of durable material that interrupts the progress of waves to shore. Harbors are often shielded by a breakwater
- Breakwater
- A worldwide change in sea level, as distinct from local changes
- eustatic change
- Movement of sediments parallel to shore, driven by wave energy
- Longshore Drift
- Water from waves washing onto a beach.
- Swash
- A reef attached to the shore of a continent or island
- Fringing Reef
- A coast exposed to large waves
- High-energy Coast
- 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 longshore trough
- Rip Current
- Sand on the seaward side of the berm, sloping toward the ocean, to the low tide mark
- foreshore
- The natural sector of a coastline in which sand input and sand outflow are balanced.
- Coastal Cell
- The zone extending from the ocean inland as far as the environment is immediately affected by marine processes
- Coast
- A current running parallel to shore in the surf zone, caused by the incomplete refraction of waves approaching the beach at an angle
- Longshore Current
- A deep, narrow estuary in a valley originally cut by a glacier
- Fjord