Submergent Coastline

-a coastline that is flooding and receding (retrogradational)

Caused either by the water level actually rising (transgression)

or by the land getting lower (Subsidence)

- may display some some emergent features

Emergent Coastline

- a coastline that is being elevated above sealevel and building out into the water (progradational)

Sea level fall is caused either by the water level actually falling (regression)

or by rising of the land ( uplift)

- may display some submergent features

Factors that Determine the characteristic landforms of Shorelines

1.  Shape of the shoreline

2.  The materials that comprise the shoreline (rock, plastic mud, loose sediment, concrete)

3.  The source and supply of sediments

4.  The direction that currents move along the shoreline

5.  The effects of major storms (a single storm can completely change the form of a coastline)

Sediment Supply

- the importance of sediment supply-

- is a major factor in determining whether a coastline is progradational or retrogradational, regardless of vertical changes of land level or water level

Features of Emergent Shorelines

              Emergence causes:

-tidal flats and coastal wetlands to expand

-wave-cut terrances are exposed to view

-deltas prograde at faster rates

-wide stable beaches develop

Features of Submergent Shorelines

As the land is flooded:

- the waves cut cliffs

- valleys are flooded to form estuaries

- wetlands are submerged

- deep bays develop

- narrow beaches form

- islands are created

Barrier Island

- a long narrow island that parrallels the mainland coastline and is seperated from the mainland by a lagoon, tidal flat, or salt marsh

-A feature of a submergent coastline

Beach

- a gently sloping deposit of sand or gravel along the edge of a shoreline

Wide stable beaches - Emergent Shorelines

Narrow beaches - Submergent shorelines

Berm Crest

- the highest part of a beach; it seperates the foreshore from the backshore

Foreshore - Seaward part of the shoreline

Backshore - landward part of the shoreline

Washover Fan

- a fan-shaped deposit of sand or gravel transported and deposited landward of the beach during a storm or very high tide

Estuary

- a river valley flooded by a rise in the level of an ocean or lake

-a feature of submergent shorelines

Fjord - a flooded glacial valley

Longshore Current

- a water current in the surf zone. It flows slowly parrallel to shoreline, driven by waves that were caused by wind

Surf Zone - Zone where waves break

Delta

- A sediment deposit at the mouth of a river where it enters an ocean or lake

Headland

- projection of land that extends into an ocean or lake and generally has cliffs along its water boundary

a feature of submergent shoreline

Spit

- a sandbar extending from the end of a beach into the mouth of an adjacent bay

Feature of both Submergent and Emeregent

Tidal Flat

- muddy or sandy area that is covered with water at high tide and exposed at low tide

Saltmarsh

- a marsh that is flooded by ocean water at high tide

Wave-cut Cliffs

- seaward facing cliff along a steep shoreline, produced by wave erosion

AKA= sea cliff

Wave-Cut Platform

- a bench or shelf at sea level (or lake level) along a steep shore, and formed by wave erosion

Marine Terrace

- an elevated platform that is bounded on its seaward side by a cliff or steep slope (and formed when a wave-cut platform is elevated by uplift or regression)

Stack

- an isolated rocky island near a headland cliff

Tombolo

- a sand bar that connects an island with the mainland or another island

Tied Island

- an island connected to the mainland or another island by a tombolo

Reasons humans build coastal structures

1.  Protect Harbors

2.  Build up sandy Beaches

3. Extend the shoreline

Sea wall

- an embankment of boulders, reinforced concrete, or other materials constructed against a shoreline to prevent erosion by waves and currents

Breakwater

- an offshore wall constructed parrallel to a shoreline to break waves

the longshore current is halted behind such walls, so the sand accumulates there and the beach widens.

Wherethe breakwater is used to protect a harbor from currents and waves, sand often collects behind the breakwater and may have to be dredged

Groin ( or Groyne)

- a short wall constructed perpendicular to shoreline in order to trap sand and make or build up a beach. Sand accumulates on the up-current side of the groin in relation to the long current

Jetties

- long walls extending from the shore at the mouths of harbors and used to protect the harbor entrance from filling with sand or being eroded by waves and currents. Jetties are usually constructed of boulders and in pairs( one on each side of the harbor or inlet)

Relict Saltmarsh Mud

- mud remaining from an ancient saltmarsh

- all of the living, surficial saltmarsh plants and animals have been stripped from this area

Reality of Sea level Fluctuation

- sea level fluctuates both above and below mean sea level during daily tidal cycles and storm surges.

daily tides cause the sea level to fluctuate 2-3 ft

The sea level could rise about 1 meter in the next century

Storm Surges

-  a bulge of water pushed landward by abnormally high winds and/or low atmospheric pressure associated with storms

- storm surges can cause the ocean to rise by about 2-24 ft depending on the magnitude of the storm

with the exception of hurricanes, most storm surges are 2-3 ft