Geology 120 Terms

Front 1

Accretion

Back 1

The accumulation or build-up of sand or other beach material due to the action of
waves, currents and wind.

Front 2

Aeolian

Back 2

From the Greek Aeolus, God of the Wind. Refers to processes or landforms formed
by action of the wind.

Front 3

Backshore

Back 3

The zone of beach lying landward of the normal high-tide line.

Front 4

Bathymetry

Back 4

The shape or topography of the seabed.

Front 5

Beach

Back 5

The seaward dipping portion of the beach over which the wave swash and backwash
operate. Two ingredients are necessary for beaches to form: waves and sediment.

Front 6

Beach cusp

Back 6

One of a series of short ridges on the foreshore separated by crescent- shaped
troughs spaced at more or less regular intervals. The cusps are spaced at somewhat
uniform distances along beaches. Cusps are typical or coarse grained reflective and
intermediate state beaches. They typically form after and not during storm events.

Front 7

Beach profile

Back 7

Topographic survey measured across the beach.

Front 8

Berm

Back 8

The nearly horizontal portion of the beach, deposited by wave action, lying
immediately landward of the beach face. The rear of the berm marks the limit of
spring high tide wave action.

Front 9

Berm crest

Back 9

The seaward limit of the berm beyond which is the steep berm face.

Front 10

Black sand

Back 10

Heavy-mineral concentrations that form by the winnowing away (by wind or water) of
the lighter sand grains. The black colour typically comes from magnetite and
ilmenite. Commonly mistaken for oil pollution.

Front 11

Coastline

Back 11

The line that is the boundary between the sea and the land. It is usually mapped as
the high water line.

Front 12

Cobbles

Back 12

Beach material of rounded rocks ranging in diameter from approximately 64 mm to
256 mm.

Front 13

Cross-shore profile

Back 13

side view of a beach extending from the top of the dune line down into the sea

Front 14

Current ripples

Back 14

Ripple marks that are short-crested and formed by water current flow such as in a
trough (runnel) on the beach.

Front 15

Cusp

Back 15

A regular undulation in the high tide swash zone (upper beach face), usually
occurring in series with spacing of 10 to 40m.

Front 16

Drag mark

Back 16

A line or pattern on the surface of the beach, produced when the wind or the swash
drags an object over the surface. Drag marks are produced by shell fragments,
clumps of seaweed, and other wrack.

Front 17

Drift line

Back 17

A mass of natural and artificial debris (e.g. seaweed, Spartina straw, fishing nets,
lumber, driftwood, plastics bottles) indicating the previous landward extent of the
high-tide line and/or wave swash.

Front 18

Dune

Back 18

A land feature formed from an accumulation of windblown sand, either bare or
covered with vegetation.

Front 19

Ebb tide

Back 19

The tidal current formed when the tide is “going out”.

Front 20

Ebb tidal delta

Back 20

The body of sand that protrudes seaward of an inlet formed by ebb tidal currents.