controlled by sea-level change. Sedimentology, doi10.1111/
J.1365.2009.01133.x.
Guilcher, A., 1988. Coral Reef Geomorphology. New York: Wiley,
228 p.
Hopley, D., 1982. Geomorphology of the Great Barrier Reef: Quaternary Development of Coral Reefs. New York: Wiley
Interscience.
Hopley, D., Smithers, S. G., and Parnell, K. E., 2007. The Geomorphology of the Great Barrier Reef: Development, Diversity, and
Change. Cambridge: Cambridge University Press, 532 p.
Mazzullo, S. J., 2006. Late Pliocene to Holocene platform evolution
in northern Belize, and comparison with coeval deposits in southern Belize and the Bahamas. Sedimentology, 53, 1015–1047.
Montaggioni, L., 2005. History of Indo-Pacific coral reef systems
since the last glaciation: development patterns and controlling
factors. Earth-Science Reviews, 1–75.
Montaggioni, L. F., Cabioch, G., Camoinau, G. F., Bard, E., RibaudLaurenti, A., Faure, G., Dejardin, P., and Recy, J., 1997. Continuous record of reef growth over the past 14 ky on the mid-Pacific
island of Tahiti. Geology, 25, 555–558.
Purdy, E., Gischler, E., and Lomando, A., 2003. The Belize margin
revisited. 2. Origin of Holocene antecedent topography. International Journal Earth Science, 92, 552–572.
Purdy, E., and Winterer, E., 2006. Contradicting barrier reef relationships for Darwin’s evolution of reef types. International
Journal Earth Science, 95, 143–167.
Purkis, S. J., Rowlands, G. P., Riegl, B. M., and Renaud, P. G., 2010.
The paradox of tropical karst morphology in the coral reefs of the
arid Middle East. Geology, 38, 227–230.
Tomascik, T., Mah, A. J., Montji, A., and Moosa, M. K., 1997. The
Ecology of the Indonesian Seas. Periplus Editions, Dalhousie 2
volumes, 1388 p.
Webster, J. M., and Davies, P. J., 2003. Coral variation in two deep
drill cores: significance for the Pleistocene development of the
Great Barrier Reef. Sedimentary Geology, 159, 61–80.
Cross-references
Belize Barrier and Atoll Reefs
Darwin, Charles (1809–1882)
Double and Triple Reef Fronts
Forereef/Reef Front
Great Barrier Reef Committee
Mururoa Atoll
New Caledonia
Reef Typology
Remote Sensing
Sea Level Change and Its Effect on Reef Growth
Subsidence Hypothesis of Reef Development
BASSETT EDGES
Roger McLean
University of New South Wales, Canberra, ACT, Australia
Synonyms
Bassett edges; Exposed edge of strata inclined upward;
Outcrop; Strike ridges.
Definition
Bassett edges are outcrops of inclined beds, forming
a jagged surface of low irregular projections resulting
from differential erosion of often steeply dipping layers
of lithified coral shingle, with a bed thickness of a few centimeters and relative relief of 2–3 dm.
A bassett is an old term used by miners in the 18th and
19th centuries to describe the emergence of subsurface geological strata at the ground surface. “Basset edges” was
introduced into the modern reef literature by J. Alfred Steers
(Steers, James Alfred (1899–1987)) to describe the lower
cemented vestiges of coral shingle ramparts on Australia’s
Great Barrier Reef, where “the separate beds are often truncated and the basset edges rise up” (Steers, 1929).
What Steers found particularly interesting was the dip
of the beds, which was “very often landward,” implying
“that the rest of the spit or ridge of shingle formerly existed
to the windward of the present outcrop.” Thus, the presence of low strike ridges that dip away from the reef front
preserve the remains of old shingle rampart systems that
have subsequently been eroded.
A more formal description and explanation of basset
edges on reefs of the northern Great Barrier Reef was
given by Scoffin and McLean (1978). They found that
(1) the inclined bedding of bassett edges represent the
cemented foreset layers of the leading edge of shingle
ramparts; (2) the irregular projections result from differential erosion related to subtle differences in the degree of
cementation and constituent texture; (3) cements are typically a chalky micrite of high magnesium calcite; (4) bedding occurs as steeply dipping foresets (40–70
) on
tongue shapes, like anticlines plunging to leeward, and as
shallowly dipping (20–40
) arcuate bands between; (5)
the inner buried portions of ramparts have to remain stationary for some time to allow lithification; and that is why
(6) bassett edges are commonly found on the central and
inner parts of a reef flat rather than toward the outer edge
where wave action continually mobilizes rampart rubble.
Though the cemented foreset beds of shingle ramparts
are not restricted to the Great Barrier Reef, the term bassett
edges is not in common use in other reef areas.
Bibliography
Scoffin, T. P., and McLean, R. F., 1978. Exposed limestones of the
northern province of the Great Barrier Reef. Philosophical
Transactions of the Royal Society, Series A, 291, 119.
Steers, J. A., 1929. The Queensland coast and the Great Barrier
Reefs. Geographical Journal, 74, 232.
Cross-references
Boulder Zone/Ramparts
Platforms (Cemented)
BEACH ROCK
Roger McLean
University of New South Wales, Canberra, ACT, Australia
Synonyms
Beach rock; Beach sandstone
BEACH ROCK
107
J.1365.2009.01133.x.
Guilcher, A., 1988. Coral Reef Geomorphology. New York: Wiley,
228 p.
Hopley, D., 1982. Geomorphology of the Great Barrier Reef: Quaternary Development of Coral Reefs. New York: Wiley
Interscience.
Hopley, D., Smithers, S. G., and Parnell, K. E., 2007. The Geomorphology of the Great Barrier Reef: Development, Diversity, and
Change. Cambridge: Cambridge University Press, 532 p.
Mazzullo, S. J., 2006. Late Pliocene to Holocene platform evolution
in northern Belize, and comparison with coeval deposits in southern Belize and the Bahamas. Sedimentology, 53, 1015–1047.
Montaggioni, L., 2005. History of Indo-Pacific coral reef systems
since the last glaciation: development patterns and controlling
factors. Earth-Science Reviews, 1–75.
Montaggioni, L. F., Cabioch, G., Camoinau, G. F., Bard, E., RibaudLaurenti, A., Faure, G., Dejardin, P., and Recy, J., 1997. Continuous record of reef growth over the past 14 ky on the mid-Pacific
island of Tahiti. Geology, 25, 555–558.
Purdy, E., Gischler, E., and Lomando, A., 2003. The Belize margin
revisited. 2. Origin of Holocene antecedent topography. International Journal Earth Science, 92, 552–572.
Purdy, E., and Winterer, E., 2006. Contradicting barrier reef relationships for Darwin’s evolution of reef types. International
Journal Earth Science, 95, 143–167.
Purkis, S. J., Rowlands, G. P., Riegl, B. M., and Renaud, P. G., 2010.
The paradox of tropical karst morphology in the coral reefs of the
arid Middle East. Geology, 38, 227–230.
Tomascik, T., Mah, A. J., Montji, A., and Moosa, M. K., 1997. The
Ecology of the Indonesian Seas. Periplus Editions, Dalhousie 2
volumes, 1388 p.
Webster, J. M., and Davies, P. J., 2003. Coral variation in two deep
drill cores: significance for the Pleistocene development of the
Great Barrier Reef. Sedimentary Geology, 159, 61–80.
Cross-references
Belize Barrier and Atoll Reefs
Darwin, Charles (1809–1882)
Double and Triple Reef Fronts
Forereef/Reef Front
Great Barrier Reef Committee
Mururoa Atoll
New Caledonia
Reef Typology
Remote Sensing
Sea Level Change and Its Effect on Reef Growth
Subsidence Hypothesis of Reef Development
BASSETT EDGES
Roger McLean
University of New South Wales, Canberra, ACT, Australia
Synonyms
Bassett edges; Exposed edge of strata inclined upward;
Outcrop; Strike ridges.
Definition
Bassett edges are outcrops of inclined beds, forming
a jagged surface of low irregular projections resulting
from differential erosion of often steeply dipping layers
of lithified coral shingle, with a bed thickness of a few centimeters and relative relief of 2–3 dm.
A bassett is an old term used by miners in the 18th and
19th centuries to describe the emergence of subsurface geological strata at the ground surface. “Basset edges” was
introduced into the modern reef literature by J. Alfred Steers
(Steers, James Alfred (1899–1987)) to describe the lower
cemented vestiges of coral shingle ramparts on Australia’s
Great Barrier Reef, where “the separate beds are often truncated and the basset edges rise up” (Steers, 1929).
What Steers found particularly interesting was the dip
of the beds, which was “very often landward,” implying
“that the rest of the spit or ridge of shingle formerly existed
to the windward of the present outcrop.” Thus, the presence of low strike ridges that dip away from the reef front
preserve the remains of old shingle rampart systems that
have subsequently been eroded.
A more formal description and explanation of basset
edges on reefs of the northern Great Barrier Reef was
given by Scoffin and McLean (1978). They found that
(1) the inclined bedding of bassett edges represent the
cemented foreset layers of the leading edge of shingle
ramparts; (2) the irregular projections result from differential erosion related to subtle differences in the degree of
cementation and constituent texture; (3) cements are typically a chalky micrite of high magnesium calcite; (4) bedding occurs as steeply dipping foresets (40–70
) on
tongue shapes, like anticlines plunging to leeward, and as
shallowly dipping (20–40
) arcuate bands between; (5)
the inner buried portions of ramparts have to remain stationary for some time to allow lithification; and that is why
(6) bassett edges are commonly found on the central and
inner parts of a reef flat rather than toward the outer edge
where wave action continually mobilizes rampart rubble.
Though the cemented foreset beds of shingle ramparts
are not restricted to the Great Barrier Reef, the term bassett
edges is not in common use in other reef areas.
Bibliography
Scoffin, T. P., and McLean, R. F., 1978. Exposed limestones of the
northern province of the Great Barrier Reef. Philosophical
Transactions of the Royal Society, Series A, 291, 119.
Steers, J. A., 1929. The Queensland coast and the Great Barrier
Reefs. Geographical Journal, 74, 232.
Cross-references
Boulder Zone/Ramparts
Platforms (Cemented)
BEACH ROCK
Roger McLean
University of New South Wales, Canberra, ACT, Australia
Synonyms
Beach rock; Beach sandstone
BEACH ROCK
107