Some Coastal Landform Definitions

Definitions of some terms used in the landform study sites of
Matthew FLINDERS & the Coastal LANDFORMS of SE Australia

An area of tidal mud flats (Port Augusta, SA)

(P) = see  PHOTO SITE  for photo that illustrates definition

bar = a buildup of beach materials lying offshore, submerged most or all of the time  (P)

barrier = a buildup of beach materials lying offshore, above sea level most or all of the time

bay = a body of water forming a coastal indentation (its mouth is wider than the magnitude of the indentation)  (P)

beach = area of buildup of coastal sediments (in Australia a beach is most commonly regarded as being composed of sand)  (P)

blowhole = aperture in the roof of a sea cave through which waves force compressed air and spray  (P)

clay = very fine-grained soil or sediment

coastal plain = low-lying zone or strip that is parallel to coastline, lying between sea and higher land  (P)

cove = a body of water forming a coastal indentation (it is smaller than a bay)  (P)

current = continuous flow of water in a particular direction

delta = an area of sediment deposition at a river's mouth

deposition = the settling of eroded, transported materials onto land surface or sea floor

drowned valley = a valley invaded by the sea through rising sea level (after the Pleistocene)  (P)

erosion = the breakdown and transportation of rock fragments from the earth's surface

estuary = the open mouth of a river, where fresh water and sea water mix  (P)

gulf = a body of water forming a coastal indentation (its mouth is narrower than the magnitude of the indentation)

headland = cliffed or steep land projecting into the sea  (P)

lagoon = a shallow coastal water body, divided from the sea by a barrier of sand  (P)

longshore drift = lateral movement of sediment in the nearshore zone as a result of wave-induced currents  (P)

mud = fine-grained to very fine-grained, usually dark-coloured coastal or river sediment

mud flats = wide area of fine sediment on seaward side of coast in sheltered waters, exposed at low tide  (P)

ocean = one of the large bodies of water surrounding the continents

peninsula = a projection of land that is almost completely surrounded by sea

platform = a flat or almost flat shelf of rock cut by waves and found at the base of some coastal cliffs  (P)

Pleistocene epoch = geological time period extending from 2 million years to 10,000 years before present

plunging coast = steep coastline which continues below sea level (and not bordered by shore platforms)  (P)

reef = rock found above or below sea level in shallow coastal waters  (P)

salt marsh = coastal zone between mangrove belt and 'dry land', subject to innundation at high tide  (P)

sand = visible fragments of rock, most commonly quartz along the coast of SE Australian  (P)

sea = a geographical division of an ocean

sea arch = eroded remnant of coastal cliff, made up of two stacks joined at the top

sea stack = usually steep-sided, eroded remnant of coastal cliff  

sediment = particles that settle on the land surface or the sea floor, from rock fragments and living things  (P)

silt = a mixture of fine-grained coastal (or river) sediments

spit = a projection of beach materials from land into the sea  (P)

surf = the turbulent parts of breaking waves at or near the coast  (P)

swell = rises in the ocean surface that are formed by wind action, and can travel large distances

tide = twice daily rise and fall of ocean waters largely caused by the moon's gravitational action

tied island = an island that has been connected to the mainland by a tombolo  (P)

tombolo = a spit that connects the mainland and an island (it has a beach on each of its sides)  (P)

undercutting = an indentation eroded by waves at the base of a cliff which may hasten cliff collapse  (P)

wave = travelling disturbance in the surface of the ocean (or other water body) usually caused by wind action  (P)

wave refraction = the bending of wave crests to parallel the sea floor's contours  (P)

A tombolo (left) and a tied island (right) (Barrenjoey Head, NSW)

C.Grant (c) 2003