facies in the rock record. Delineation of individual
backbarrier facies is often difficult due to bioturbation,
reactivation, and reworking.
Bibliography
Bartholdy, A. T., Bartholdy, J., and Kroon, A., 2010. Salt marsh stability and patterns of sedimentation across a backbarrier platform. Marine Geology, 278, 31–42.
Carrasco, A. R., Ferreira, O., Davidson, M., Matias, A., and Dias, J.,
2008. An evolutionary categorisation model for backbarrier
environments. Marine Geology, 251, 156–166.
Carter, R. W. G., 1988. Coastal Environments: An Introduction to
the Physical, Ecological and Cultural Systems of Coastlines.
New York: Academic Press.
Cooper, J. A. G., 1994. Lagoons and microtidal coasts. In Carter, R.,
and Woodroffe, C. (eds.), Coastal Evolution: Late Quaternary
Shoreline Morphodynamics. Cambridge: Cambridge University
Press, pp. 121–186.
Davis, R. A., and Fitzgerald, D. M., 2004. Beaches and Coasts.
Malden, MA: Blackwell.
Fisher, S. J., Leatherman, S. P., and Perry, F. C., 1974. Overwash
processes on Assateague Island. In Proceedings of 14th Conference on Coastal Engineering, New York, American Society of
Civil Engineers, pp. 1194–1211.
French, J., and Spencer, T., 1993. Dynamics of sedimentation in
a tide-dominated backbarrier salt marsh, Norfolk, UK. Marine
Geology, 110, 315–331.
Friedman, G. M., Sanders, J. E., and Kopaska-Merkel, D. C., 1992.
Principles of Sedimentary Deposits. New York: Macmillan.
Godfrey, P. J., and Godfrey, M. M., 1974. The role of overwash and
inlet dynamics in the formation of salt marshes on North Carolina Barrier Islands. In Reimold, R. J., and Queen, W. H. (eds.),
Ecology of Halophytes. New York: Academic Press,
pp. 409–427.
Howard, J. D., and Frey, R. W., 1985. Physical and biogenic aspects
of backbarrier sediment systems, Georgia coast, USA. Marine
Geology, 63, 77–127.
Kraft, J. C., Allen, E. A., Belknap, D. F., John, C. J., and Maurmeyers,
E. M., 1979. Processes and morphologic evolution of an estuarine
and coastal barrier system. In Leatherman, S. P. (ed.), Barrier
Islands from the Gulf of St. Lawrence to the Gulf of Mexico.
New York: Academic Press, pp. 149–184.
McCubbin, D. G., 1982. Barrier island and strand plain facies. In
Scholle, P. A., and Spearing, D. (eds.), Sandstone Depositional
Environments. Tulsa, OK: American Association of Petroleum
Geologists, pp. 247–280.
Morton, R. A., and Sallenger, A. H., 2003. Morphological impacts
of extreme storms on sandy beaches and barriers. Journal of
Coastal Research, 19, 560–573.
Moslow, T. F., and Tye, R. S., 1985. Recognition and characterization of Holocene tidal inlet sequences. Marine Geology, 63,
129–151.
Oertel, G. F., 1985. The barrier island system. Marine Geology, 63,
1–18.
Reineck, H. E., and Wunderlich, F., 1968. Classification and origin
of flaser and lenticular bedding. Sedimentology, 11, 99–104.
Ritchie, W., and Penland, S., 1988. Rapid dune changes associated
with overwash processes on the deltaic coast of South Louisiana.
Marine Geology, 81, 97–122.
Schwartz, R. K., 1981. Nature and genesis of some storm washover
deposits. In Leatherman, S. (ed.), Overwash Processes.
Stroudsburg, PA: Hutchinson Ross Publications, pp. 229–257.
Sedgwick, P. E., and Davis, R. A., 2003. Stratigraphy of washover
deposits in Florida; implications for recognition in the stratigraphic record. Marine Geology, 200, 31–48.
Cross-references
Back Dune
Barrier Island
Barrier Spits
Beach Processes
Coastal Barriers
Coastal Lagoons
Coastal Landforms
Estuarine Beaches
Estuarine Geomorphology
Intertidal Zonation
Overwash
Saltmarshes
Washover Fans
Washovers
BAR
J. Javier Diez
1 and Efren M. Veiga
2
1
Research Group on Marine, Coastal and Port
Environment and Other Sensitive Areas, Department of
Land and Urban Planning and Environment,
Universidad Politécnica de Madrid, Madrid, Spain
2
Civil Engineering: Land & Urban Management and
Environment, Universidad Politécnica de Madrid, Escuela
de Caminos, Canales y Puertos, Madrid, Spain
Synonyms
Sand bank; Sand bar
Definition
The term bar refers to a step or projection in the cross profile of a beach. While a bar may have slightly different
meanings when used by different authors (King, 1972;
Finkl, 2004), in all cases the term can be linked to the
transformative action of waves when they approach the
coastline over a sea bottom that consists of non-cohesive
granular sediment.
The concept of a bar is relevant for interpreting data and
gaining knowledge of almost all sedimentary coastal formations such as cordons, barrier (sedimentary) islands,
hooks, spits, cuspate forelands, and tombolos. For detailed
analyses of such formations (Williams, 1982), the Genetic
Classification of Simple Coastal Forms (Bores, 1978) is
a valuable resource.
Genesis
Water depth gradually decreases as a wave approaches the
coast, and mass transport is accentuated because of the
asymmetry of the open wave orbital motion. Thus, sea
bottom sediments are dragged up toward the breaker line,
which generates an increasingly stepped slope toward the
shore and carves out a concave profile. Wave motion stops
at the breaker line in a tide-free sea, and the cross profile
exhibits a geometric discontinuity in that location. This
discontinuity is the bar.
46
BAR
backbarrier facies is often difficult due to bioturbation,
reactivation, and reworking.
Bibliography
Bartholdy, A. T., Bartholdy, J., and Kroon, A., 2010. Salt marsh stability and patterns of sedimentation across a backbarrier platform. Marine Geology, 278, 31–42.
Carrasco, A. R., Ferreira, O., Davidson, M., Matias, A., and Dias, J.,
2008. An evolutionary categorisation model for backbarrier
environments. Marine Geology, 251, 156–166.
Carter, R. W. G., 1988. Coastal Environments: An Introduction to
the Physical, Ecological and Cultural Systems of Coastlines.
New York: Academic Press.
Cooper, J. A. G., 1994. Lagoons and microtidal coasts. In Carter, R.,
and Woodroffe, C. (eds.), Coastal Evolution: Late Quaternary
Shoreline Morphodynamics. Cambridge: Cambridge University
Press, pp. 121–186.
Davis, R. A., and Fitzgerald, D. M., 2004. Beaches and Coasts.
Malden, MA: Blackwell.
Fisher, S. J., Leatherman, S. P., and Perry, F. C., 1974. Overwash
processes on Assateague Island. In Proceedings of 14th Conference on Coastal Engineering, New York, American Society of
Civil Engineers, pp. 1194–1211.
French, J., and Spencer, T., 1993. Dynamics of sedimentation in
a tide-dominated backbarrier salt marsh, Norfolk, UK. Marine
Geology, 110, 315–331.
Friedman, G. M., Sanders, J. E., and Kopaska-Merkel, D. C., 1992.
Principles of Sedimentary Deposits. New York: Macmillan.
Godfrey, P. J., and Godfrey, M. M., 1974. The role of overwash and
inlet dynamics in the formation of salt marshes on North Carolina Barrier Islands. In Reimold, R. J., and Queen, W. H. (eds.),
Ecology of Halophytes. New York: Academic Press,
pp. 409–427.
Howard, J. D., and Frey, R. W., 1985. Physical and biogenic aspects
of backbarrier sediment systems, Georgia coast, USA. Marine
Geology, 63, 77–127.
Kraft, J. C., Allen, E. A., Belknap, D. F., John, C. J., and Maurmeyers,
E. M., 1979. Processes and morphologic evolution of an estuarine
and coastal barrier system. In Leatherman, S. P. (ed.), Barrier
Islands from the Gulf of St. Lawrence to the Gulf of Mexico.
New York: Academic Press, pp. 149–184.
McCubbin, D. G., 1982. Barrier island and strand plain facies. In
Scholle, P. A., and Spearing, D. (eds.), Sandstone Depositional
Environments. Tulsa, OK: American Association of Petroleum
Geologists, pp. 247–280.
Morton, R. A., and Sallenger, A. H., 2003. Morphological impacts
of extreme storms on sandy beaches and barriers. Journal of
Coastal Research, 19, 560–573.
Moslow, T. F., and Tye, R. S., 1985. Recognition and characterization of Holocene tidal inlet sequences. Marine Geology, 63,
129–151.
Oertel, G. F., 1985. The barrier island system. Marine Geology, 63,
1–18.
Reineck, H. E., and Wunderlich, F., 1968. Classification and origin
of flaser and lenticular bedding. Sedimentology, 11, 99–104.
Ritchie, W., and Penland, S., 1988. Rapid dune changes associated
with overwash processes on the deltaic coast of South Louisiana.
Marine Geology, 81, 97–122.
Schwartz, R. K., 1981. Nature and genesis of some storm washover
deposits. In Leatherman, S. (ed.), Overwash Processes.
Stroudsburg, PA: Hutchinson Ross Publications, pp. 229–257.
Sedgwick, P. E., and Davis, R. A., 2003. Stratigraphy of washover
deposits in Florida; implications for recognition in the stratigraphic record. Marine Geology, 200, 31–48.
Cross-references
Back Dune
Barrier Island
Barrier Spits
Beach Processes
Coastal Barriers
Coastal Lagoons
Coastal Landforms
Estuarine Beaches
Estuarine Geomorphology
Intertidal Zonation
Overwash
Saltmarshes
Washover Fans
Washovers
BAR
J. Javier Diez
1 and Efren M. Veiga
2
1
Research Group on Marine, Coastal and Port
Environment and Other Sensitive Areas, Department of
Land and Urban Planning and Environment,
Universidad Politécnica de Madrid, Madrid, Spain
2
Civil Engineering: Land & Urban Management and
Environment, Universidad Politécnica de Madrid, Escuela
de Caminos, Canales y Puertos, Madrid, Spain
Synonyms
Sand bank; Sand bar
Definition
The term bar refers to a step or projection in the cross profile of a beach. While a bar may have slightly different
meanings when used by different authors (King, 1972;
Finkl, 2004), in all cases the term can be linked to the
transformative action of waves when they approach the
coastline over a sea bottom that consists of non-cohesive
granular sediment.
The concept of a bar is relevant for interpreting data and
gaining knowledge of almost all sedimentary coastal formations such as cordons, barrier (sedimentary) islands,
hooks, spits, cuspate forelands, and tombolos. For detailed
analyses of such formations (Williams, 1982), the Genetic
Classification of Simple Coastal Forms (Bores, 1978) is
a valuable resource.
Genesis
Water depth gradually decreases as a wave approaches the
coast, and mass transport is accentuated because of the
asymmetry of the open wave orbital motion. Thus, sea
bottom sediments are dragged up toward the breaker line,
which generates an increasingly stepped slope toward the
shore and carves out a concave profile. Wave motion stops
at the breaker line in a tide-free sea, and the cross profile
exhibits a geometric discontinuity in that location. This
discontinuity is the bar.
46
BAR