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| Titel |
A 6,700 years sea-level record based on French Polynesian coral reefs |
| VerfasserIn |
Nadine Hallmann, Gilbert Camoin, Anton Eisenhauer, Claude Vella, Elias Samankassou, Alberic Botella, Glenn Milne, Jan Fietzke, Philippe Dussouillez |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107631
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| Publikation (Nr.) |
 EGU/EGU2015-10356.pdf |
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| Zusammenfassung |
| Sea-level change during the Mid- to Late Holocene has a similar amplitude to the sea-level
rise that is likely to occur before the end of the 21st century providing a unique opportunity to
study the coastal response to sea-level change and to reveal an important baseline of natural
climate variability prior to the industrial revolution.
Mid- to Late Holocene relative sea-level change in French Polynesia was reconstructed
using coral reef records from ten islands, which represent ideal settings for accurate sea-level
studies because: 1) they can be regarded as tectonically stable during the relevant period
(slow subsidence), 2) they are located far from former ice sheets (far-field), 3) they are
characterized by a low tidal amplitude, and 4) they cover a wide range of latitudes which
produces significantly improved constraints on GIA (Glacial Isostatic Adjustment) model
parameters.
Absolute U/Th dating of in situ coral colonies and their accurate positioning via GPS
RTK (Real Time Kinematic) measurements is crucial for an accurate reconstruction of
sea-level change. We focus mainly on the analysis of coral microatolls, which are sensitive
low-tide recorders, as their vertical accretion is limited by the mean low water springs level.
Growth pattern analysis allows the reconstruction of low-amplitude, high-frequency sea-level
changes on centennial to sub-decadal time scales.
A sea-level rise of less than 1 m is recorded between 6 and 3–3.5 ka, and is followed by a
gradual fall in sea level that started around 2.5 ka and persisted until the past few centuries.
The reconstructed sea-level curve therefore extends the Tahiti sea-level curve [Deschamps
et al., 2012, Nature, 483, 559-564], and is in good agreement with a geophysical
model tuned to fit far-field deglacial records [Bassett et al., 2005, Science, 309,
925-928]. |
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