generation. Pure and Applied Geophysics, 160, 2087–2118,
doi:10.1007/s00024–003–2421–1.
Scheffers, A., and Kelletat, K., 2003. Sedimentologic and
geomorphologic tsunami imprints worldwide – A review.
Earth-Science Reviews, 63, 83–92, doi:10.1016/S0012–8252
(03)00018–7.
Simkin, T., and Fiske, R. S., 1983. Kratatau 1883: The Volcanic
Eruption and its Effects. Washington, DC: Smithsonian Institution Press.
Spiske, M., Böröcz, Z., and Bahlburg, H., 2008. The role of porosity
in discriminating between hurricane and tsunami emplacement
of boulders – A case study from the Lesser Antilles, southern
Caribbean. Earth and Planetary Science Letters, 268,
384–396, doi:10.1016/j.epsl.2008.01.030.
Suzuki, A., Yokoyama, Y., Kan, H, Minoshima, K., Matsuzaki, H.,
Hamanaka, N., and Kawahata, H., 2008. Identification of 1771
Meiwa tsunami deposits using a combination of radiocarbon dating and isotope microprofiling of emerged massive Porites boulders. Quaternary Geochronology, 3, 226–234, doi:10.1016/
j.quageo.2007.12.002.
Ward, S. N., and Day, S., 2001. Cumbre Vieja volcano - Potential
collapse and tsunami at La Palma, Canary Islands. Geophysical
Research Letters, 28, 3397–3400, doi:10.1029/2001GL013110.
Zhao, J.-X., Nell, D. T., Feng, Y.-X., and Pandolfi, J. M., 2009.
High-precision U-series dating of very young cyclonetransported coral reef blocks from Heron and Wistari reefs,
southern Great Barrier Reef, Australia. Quaternary International,
195, 122–127, doi:10.1016/j.quaint.2008.06.004.
Cross-references
Boulder Beaches
Earthquakes and Emergence or Submergence of Coral Reefs
Last Interglacial and Reef Development
Recent Sea Level Trends
Tsunami
MELTWATER PULSES
Paul Blanchon
National Autonomous University of Mexico, Cancun,
Mexico
Synonyms
Catastrophic [sea-level] rise event; Sea-level jump
Definition
A meltwater pulse is an acceleration in sea-level rise
which results from outbursts of pro- or subglacial meltwater and/or surging of ice-streams into the ocean during icesheet disintegration. Radiometric ages of coral-reef
drowning and back-stepping indicate that rates of sealevel rise during these meltwater pulses were at least
35 mm/yr and may have been as much as 60 mm/yr, and
that these rises persisted for 300–500 years.
Introduction
Measuring the age and elevation of late Quaternary reefcrest corals has enabled geoscientists to reconstruct the
rate and magnitude of relative sea-level rise at several sites
and identify global episodes of rapid sea-level rise that
resulted from pulses of meltwater or iceburg discharge
during the disintegration of ice sheets (Fairbanks, 1989;
Blanchon and Shaw, 1995). These reconstructions show
that the rate and magnitude of sea-level jumps were truly
astonishing. Coastal and shallow marine ecosystems were
inundated by rises of as much as 15 m at rates of up to
60 mm/yr. It is no surprise that understanding their causes
and consequences has subsequently become the focus of
a large multi-disciplinary research effort with particular
emphasis on how they may relate to possible future rapid
climate and sea-level change.
Glacial Termination I (MIS-2)
Pulses in melt-water discharge during the last deglaciation
were first reported by Fairbanks (1989) from an analysis
of drowned reef-crest sequences cored off the south coast
of Barbados. By plotting age/depth data from the reefcrest coral Acropora palmata in these cores and correcting
them for tectonic uplift (0.34 mm/yr), he reconstructed
sea-level rise during the last deglaciation between
17,100 and 7,800 radiocarbon years ago. From this curve,
he identified two “exceedingly rapid” rise events separated by a period of reduced melting, and estimated that
the first event, melt-water pulse 1a (Mwp-1a), was a rise
of 24 m in less than 1,000 years centered at 12,000 radiocarbon years BP, and the second event, melt-water pulse
1b (Mwp-1b), was a rise of 28 m centered at 9,500 radiocarbon years BP. Fairbanks suggested that these rapid-rise
events corresponded to the most intense phases of seasonal melt-water discharge during the disintegration of
Northern Hemisphere ice-sheets, and estimated discharge
rates of 14,000 km
3
/yr and 9500 km
3
/yr, respectively. In
later studies, he and co-workers re-dated all samples using
more precise
230 Th ages (Bard et al., 1990; Fairbanks
et al., 2005) and produced a curve showing that Mwp-1a
was centered at 14,000 years, with a period of reduced
melting between 13kyrs and 11 kyrs, and Mwp-1b was
centered at 11,000 years BP (Figure 1).
However, these meltwater pulses coincided with gaps
between cores which led some to argue that they were artifacts resulting from non-uniform uplift, or from the postgrowth collapse of reef deposits themselves (see
discussion in Broecker, 1990; Bard et al., 1996; Radtke
and Schellmann, 2006). To rule out this possibility, evidence of reef-drowning from other areas was required.
That evidence was reported by Blanchon and Shaw
(1995) who determined that elevations of drowned
A. palmata reefs in the Caribbean-Atlantic reef province
were consistent with the stepped pattern of sea-level rise
identified from Barbados. By combining the previously
reported coral ages with stratigraphic data, including the
positions of A. palmata framework, intervening gaps,
and the transitional thickness between units, they further
constrained the timing, rate, and magnitude of these
melt-water pulses and calculated that Mwp-1a was
a 13.5 m rise in 290 years centered at 14,200 years, there
MELTWATER PULSES
683
doi:10.1007/s00024–003–2421–1.
Scheffers, A., and Kelletat, K., 2003. Sedimentologic and
geomorphologic tsunami imprints worldwide – A review.
Earth-Science Reviews, 63, 83–92, doi:10.1016/S0012–8252
(03)00018–7.
Simkin, T., and Fiske, R. S., 1983. Kratatau 1883: The Volcanic
Eruption and its Effects. Washington, DC: Smithsonian Institution Press.
Spiske, M., Böröcz, Z., and Bahlburg, H., 2008. The role of porosity
in discriminating between hurricane and tsunami emplacement
of boulders – A case study from the Lesser Antilles, southern
Caribbean. Earth and Planetary Science Letters, 268,
384–396, doi:10.1016/j.epsl.2008.01.030.
Suzuki, A., Yokoyama, Y., Kan, H, Minoshima, K., Matsuzaki, H.,
Hamanaka, N., and Kawahata, H., 2008. Identification of 1771
Meiwa tsunami deposits using a combination of radiocarbon dating and isotope microprofiling of emerged massive Porites boulders. Quaternary Geochronology, 3, 226–234, doi:10.1016/
j.quageo.2007.12.002.
Ward, S. N., and Day, S., 2001. Cumbre Vieja volcano - Potential
collapse and tsunami at La Palma, Canary Islands. Geophysical
Research Letters, 28, 3397–3400, doi:10.1029/2001GL013110.
Zhao, J.-X., Nell, D. T., Feng, Y.-X., and Pandolfi, J. M., 2009.
High-precision U-series dating of very young cyclonetransported coral reef blocks from Heron and Wistari reefs,
southern Great Barrier Reef, Australia. Quaternary International,
195, 122–127, doi:10.1016/j.quaint.2008.06.004.
Cross-references
Boulder Beaches
Earthquakes and Emergence or Submergence of Coral Reefs
Last Interglacial and Reef Development
Recent Sea Level Trends
Tsunami
MELTWATER PULSES
Paul Blanchon
National Autonomous University of Mexico, Cancun,
Mexico
Synonyms
Catastrophic [sea-level] rise event; Sea-level jump
Definition
A meltwater pulse is an acceleration in sea-level rise
which results from outbursts of pro- or subglacial meltwater and/or surging of ice-streams into the ocean during icesheet disintegration. Radiometric ages of coral-reef
drowning and back-stepping indicate that rates of sealevel rise during these meltwater pulses were at least
35 mm/yr and may have been as much as 60 mm/yr, and
that these rises persisted for 300–500 years.
Introduction
Measuring the age and elevation of late Quaternary reefcrest corals has enabled geoscientists to reconstruct the
rate and magnitude of relative sea-level rise at several sites
and identify global episodes of rapid sea-level rise that
resulted from pulses of meltwater or iceburg discharge
during the disintegration of ice sheets (Fairbanks, 1989;
Blanchon and Shaw, 1995). These reconstructions show
that the rate and magnitude of sea-level jumps were truly
astonishing. Coastal and shallow marine ecosystems were
inundated by rises of as much as 15 m at rates of up to
60 mm/yr. It is no surprise that understanding their causes
and consequences has subsequently become the focus of
a large multi-disciplinary research effort with particular
emphasis on how they may relate to possible future rapid
climate and sea-level change.
Glacial Termination I (MIS-2)
Pulses in melt-water discharge during the last deglaciation
were first reported by Fairbanks (1989) from an analysis
of drowned reef-crest sequences cored off the south coast
of Barbados. By plotting age/depth data from the reefcrest coral Acropora palmata in these cores and correcting
them for tectonic uplift (0.34 mm/yr), he reconstructed
sea-level rise during the last deglaciation between
17,100 and 7,800 radiocarbon years ago. From this curve,
he identified two “exceedingly rapid” rise events separated by a period of reduced melting, and estimated that
the first event, melt-water pulse 1a (Mwp-1a), was a rise
of 24 m in less than 1,000 years centered at 12,000 radiocarbon years BP, and the second event, melt-water pulse
1b (Mwp-1b), was a rise of 28 m centered at 9,500 radiocarbon years BP. Fairbanks suggested that these rapid-rise
events corresponded to the most intense phases of seasonal melt-water discharge during the disintegration of
Northern Hemisphere ice-sheets, and estimated discharge
rates of 14,000 km
3
/yr and 9500 km
3
/yr, respectively. In
later studies, he and co-workers re-dated all samples using
more precise
230 Th ages (Bard et al., 1990; Fairbanks
et al., 2005) and produced a curve showing that Mwp-1a
was centered at 14,000 years, with a period of reduced
melting between 13kyrs and 11 kyrs, and Mwp-1b was
centered at 11,000 years BP (Figure 1).
However, these meltwater pulses coincided with gaps
between cores which led some to argue that they were artifacts resulting from non-uniform uplift, or from the postgrowth collapse of reef deposits themselves (see
discussion in Broecker, 1990; Bard et al., 1996; Radtke
and Schellmann, 2006). To rule out this possibility, evidence of reef-drowning from other areas was required.
That evidence was reported by Blanchon and Shaw
(1995) who determined that elevations of drowned
A. palmata reefs in the Caribbean-Atlantic reef province
were consistent with the stepped pattern of sea-level rise
identified from Barbados. By combining the previously
reported coral ages with stratigraphic data, including the
positions of A. palmata framework, intervening gaps,
and the transitional thickness between units, they further
constrained the timing, rate, and magnitude of these
melt-water pulses and calculated that Mwp-1a was
a 13.5 m rise in 290 years centered at 14,200 years, there
MELTWATER PULSES
683