classifies the land along a coast, especially when thinking
of its shape or appearance, as, for example, in British
Columbia’s rugged coastline around Puget Sound. Classification of coast in terms of materials such as sand to
a layman refers to a large area of sand on a beach.
Although these concepts of coast are useful to laypersons,
more rigorous definitions are required for technical applications where scientists and engineers need more detailed
information about materials making up the coast (types of
rocks and sediments), shape and configuration of landforms along the coast, natural processes operating around
the coast (climate, waves, currents), tectonics, sea-level
change, coastal-marine ecology, etc.
Organization of different types of coasts into
a classification system thus seems simple enough, but as
it turns out, the pigeon holing of variants has been elusive
(Finkl, 2004). Although it is a natural tendency to try and
classify coasts, no universal classification of coasts has yet
been put forth. Problems thwarting attempts to classify
coasts are legion, but they mostly arise from scalar considerations, the multidimensionality of coasts, and polymorphism that is associated with the concurrence of paleoand neomorphs along the same coastal segment. The compound nature of coasts often makes it difficult to classify
coast according to one type or another, as, for example,
when beaches occur seaward of cliffs or as pocket beaches
along rocky coasts. Percentage frequencies of occurrence
of a particular coastal type may thus overlap if more than
one type occurs along a coastal segment, as indicated previously where beaches may occur in front (seaward) of
rocky cliffs. Estimates of worldwide coastal types thus differ, and percentage frequency of occurrence overlaps due
to the compound nature of many coastal segments. Different types of coasts result from a wide range of processes
(e.g., Zenkovich, 1967; Bird, 1985; Fairbridge, 1989;
Short, 1999; Woodroffe, 2002) and exhibit distinctive spatial distribution patterns of landforms (e.g., Davies, 1964,
1980) that give character to coastal segments to identify
them as sandy, muddy, cliffy, rocky coast, etc.
Previous investigations propose that several salient factors should be taken into account when devising a coastal
classification (cf. King, 1966; Davies, 1964, 1980; Bird,
1976; Fairbridge, 1989, 1992; Finkl, 2004): (1) the shape
or form (morphology) of the land surface (above and
below sea-level), (2) the movement of sea-level relative
to the land and vice versa (e.g., change in relative sealevel, RSL), (3) modifying effects of marine processes,
(4) climatic influences on process and form, and (5) age
and durability of coastal materials. The following examples illustrate the point of proposed terminologies, viz.,
Atlantic and Pacific type coasts (Suess, 1888); subduction,
taphrogenic (rifted), and sediment-loading (alluvial)
coasts (Fairbridge, 1992); coastlines of submergence and
emergence (Johnson, 1919); primary and secondary
coasts (Shepard, 1973); advancing and retreating coasts
(Valentin, 1952); soil and unconsolidated coast forms
(e.g., cliff, platform, reef); solid and unconsolidated coast
materials (e.g., beach, delta, channel, flats, scree/talus)
(Owens, 1994); coasts of plate boundary islands and intraplate islands (Nunn, 1994); coasts of shelf coral reefs
(patch reefs, crescentic reefs, lagoonal reefs, planar reefs)
(Hopley, 1988); coast of unvegetated solitary island, vegetated solitary island, multiple islands, and complex low
wooded islands (Stoddart and Steers, 1978); reef coasts
(fringing reefs, bank reefs, barrier reefs, atolls, ridge reefs,
Bahamian reefs) (Guilcher, 1988); beach coast (dissipative, intermediate, reflective beaches) (Short, 1999); Type
A coast platforms (e.g., benches (Zenkovitch, 1967), platforms (Trenhaile, 1987), wave-cut terraces (Leet and
Judson, 1958), wave-cut platforms (King, 1963)) and
Type B coast platforms (e.g., coastal platforms (Guilcher,
1958), marine benches (Cotton, 1963), wave-cut platforms (Short, 1982)); sea cliffs (plunging, composite)
(Davis, 1898; Orme, 1962); etc.
All of a sudden the concept of coast becomes very complicated and far-removed from the realm of laypersons as
geoscientific terminologies make headway into the literature. The jargon surrounding the term coast is necessary
because the term, which at first sight seems simple
enough, is actually complex. This is because the perception of coast is not only scale dependent but time dependent as well where old and new landforms are
juxtaposed along many coasts. An additional classificatory complication is that coasts are dynamic and constantly changing to the point that the study of coastal
(coastline) change takes on a wide purview among
researchers, especially in regard to identification and evaluation of evident and potential change associated with variations in sea-level (e.g., Bird, 1985; Fairbridge, 1989;
Woodroffe, 2002). New technologies associated with
remote sensing capabilities now facilitate the recognition
and classification of coasts in terms of natural landform
features, ecosystems, and processes (e.g., Shaw et al.
2008; Wang et al., 2010; and Klemas, 2011).
Coastal landforms
Landforms and ecosystems often provide specificity to
different types of coasts, and it is perhaps useful to indicate some notable examples. The modifier before the noun
coast (e.g., cliffy coast, sandy coast, mangrove coast,
skerry coast) or as a noun by itself to signify a specific
kind of coast (e.g., estuary, rocky headland, spit, tombolo)
helps project an image of what is being described. There
is, however, great variation in scale within a single coast
designation as in the example of estuarine coasts where
the St. Lawrence Estuary (Canada) is the longest
(1,197 km) in the world followed by Chesapeake Bay
(United States) (322 km) to very small estuaries along
many coasts of the world.
Rocky coasts
Whereas rocky coasts in general make up about 80 % of
the world coast length (Emery and Kuhn, 1980), sea cliffs
(Figure 1) are distinctive and dramatic forms of rocky
coasts that make up about half of the world’s coasts, but
106
COASTS
of its shape or appearance, as, for example, in British
Columbia’s rugged coastline around Puget Sound. Classification of coast in terms of materials such as sand to
a layman refers to a large area of sand on a beach.
Although these concepts of coast are useful to laypersons,
more rigorous definitions are required for technical applications where scientists and engineers need more detailed
information about materials making up the coast (types of
rocks and sediments), shape and configuration of landforms along the coast, natural processes operating around
the coast (climate, waves, currents), tectonics, sea-level
change, coastal-marine ecology, etc.
Organization of different types of coasts into
a classification system thus seems simple enough, but as
it turns out, the pigeon holing of variants has been elusive
(Finkl, 2004). Although it is a natural tendency to try and
classify coasts, no universal classification of coasts has yet
been put forth. Problems thwarting attempts to classify
coasts are legion, but they mostly arise from scalar considerations, the multidimensionality of coasts, and polymorphism that is associated with the concurrence of paleoand neomorphs along the same coastal segment. The compound nature of coasts often makes it difficult to classify
coast according to one type or another, as, for example,
when beaches occur seaward of cliffs or as pocket beaches
along rocky coasts. Percentage frequencies of occurrence
of a particular coastal type may thus overlap if more than
one type occurs along a coastal segment, as indicated previously where beaches may occur in front (seaward) of
rocky cliffs. Estimates of worldwide coastal types thus differ, and percentage frequency of occurrence overlaps due
to the compound nature of many coastal segments. Different types of coasts result from a wide range of processes
(e.g., Zenkovich, 1967; Bird, 1985; Fairbridge, 1989;
Short, 1999; Woodroffe, 2002) and exhibit distinctive spatial distribution patterns of landforms (e.g., Davies, 1964,
1980) that give character to coastal segments to identify
them as sandy, muddy, cliffy, rocky coast, etc.
Previous investigations propose that several salient factors should be taken into account when devising a coastal
classification (cf. King, 1966; Davies, 1964, 1980; Bird,
1976; Fairbridge, 1989, 1992; Finkl, 2004): (1) the shape
or form (morphology) of the land surface (above and
below sea-level), (2) the movement of sea-level relative
to the land and vice versa (e.g., change in relative sealevel, RSL), (3) modifying effects of marine processes,
(4) climatic influences on process and form, and (5) age
and durability of coastal materials. The following examples illustrate the point of proposed terminologies, viz.,
Atlantic and Pacific type coasts (Suess, 1888); subduction,
taphrogenic (rifted), and sediment-loading (alluvial)
coasts (Fairbridge, 1992); coastlines of submergence and
emergence (Johnson, 1919); primary and secondary
coasts (Shepard, 1973); advancing and retreating coasts
(Valentin, 1952); soil and unconsolidated coast forms
(e.g., cliff, platform, reef); solid and unconsolidated coast
materials (e.g., beach, delta, channel, flats, scree/talus)
(Owens, 1994); coasts of plate boundary islands and intraplate islands (Nunn, 1994); coasts of shelf coral reefs
(patch reefs, crescentic reefs, lagoonal reefs, planar reefs)
(Hopley, 1988); coast of unvegetated solitary island, vegetated solitary island, multiple islands, and complex low
wooded islands (Stoddart and Steers, 1978); reef coasts
(fringing reefs, bank reefs, barrier reefs, atolls, ridge reefs,
Bahamian reefs) (Guilcher, 1988); beach coast (dissipative, intermediate, reflective beaches) (Short, 1999); Type
A coast platforms (e.g., benches (Zenkovitch, 1967), platforms (Trenhaile, 1987), wave-cut terraces (Leet and
Judson, 1958), wave-cut platforms (King, 1963)) and
Type B coast platforms (e.g., coastal platforms (Guilcher,
1958), marine benches (Cotton, 1963), wave-cut platforms (Short, 1982)); sea cliffs (plunging, composite)
(Davis, 1898; Orme, 1962); etc.
All of a sudden the concept of coast becomes very complicated and far-removed from the realm of laypersons as
geoscientific terminologies make headway into the literature. The jargon surrounding the term coast is necessary
because the term, which at first sight seems simple
enough, is actually complex. This is because the perception of coast is not only scale dependent but time dependent as well where old and new landforms are
juxtaposed along many coasts. An additional classificatory complication is that coasts are dynamic and constantly changing to the point that the study of coastal
(coastline) change takes on a wide purview among
researchers, especially in regard to identification and evaluation of evident and potential change associated with variations in sea-level (e.g., Bird, 1985; Fairbridge, 1989;
Woodroffe, 2002). New technologies associated with
remote sensing capabilities now facilitate the recognition
and classification of coasts in terms of natural landform
features, ecosystems, and processes (e.g., Shaw et al.
2008; Wang et al., 2010; and Klemas, 2011).
Coastal landforms
Landforms and ecosystems often provide specificity to
different types of coasts, and it is perhaps useful to indicate some notable examples. The modifier before the noun
coast (e.g., cliffy coast, sandy coast, mangrove coast,
skerry coast) or as a noun by itself to signify a specific
kind of coast (e.g., estuary, rocky headland, spit, tombolo)
helps project an image of what is being described. There
is, however, great variation in scale within a single coast
designation as in the example of estuarine coasts where
the St. Lawrence Estuary (Canada) is the longest
(1,197 km) in the world followed by Chesapeake Bay
(United States) (322 km) to very small estuaries along
many coasts of the world.
Rocky coasts
Whereas rocky coasts in general make up about 80 % of
the world coast length (Emery and Kuhn, 1980), sea cliffs
(Figure 1) are distinctive and dramatic forms of rocky
coasts that make up about half of the world’s coasts, but
106
COASTS