Rapid sea-level rise and reef back-stepping at the close of the last interglacial highstand
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Material Information

Title:
Rapid sea-level rise and reef back-stepping at the close of the last interglacial highstand
Series Title:
Nature Magazine Volume 458
Creator:
Blanchon, Paul
Eisenhauer, Anton
Fietzke, Jan
Liebetrau, Volker
Publisher:
Macmillan Publishers Limited
Publication Date:
Language:
English

Subjects

Subjects / Keywords:
Sea level rise ( lcsh )
Reefs ( lcsh )
Ice sheets ( lcsh )

Notes

Abstract:
Widespread evidence of a 14–6-m sea-level highstand during the last interglacial period (Marine Isotope Stage 5e) has led towarnings that modern ice sheets will deteriorate owing to global warming and initiate a rise of similarmagnitude by AD 2100 (ref. 1).The rate of this projected rise is based on ice-sheet melting simulations and downplays discoveries ofmore rapid ice loss2,3. Knowing the rate atwhich sea level reached its highstand during the last interglacial period is fundamental in assessing if such rapid ice-loss processes could lead to future catastrophic sea-level rise.The bestdirect recordof sea level during this highstand comes from well-dated fossil reefs in stable areas4–6. However, this record lacks both reef-crest development up to the full highstand elevation, as inferred7 from widespread intertidal indicators at 16m, and a detailed chronology, owing to the difficulty of replicating U-series ages on submillennial timescales8. Here we present a complete reef-crest sequence for the last interglacial highstand and its U-series chronology fromthe stable northeast Yucata´n peninsula, Mexico. We find that reef development during the highstand was punctuated by reef-crest demise at 13m and back-stepping to 16m. The abrupt demise of the lower-reef crest, but continuous accretion between the lower-lagoonal unit and the upper-reef crest, allows us to infer that this back-stepping occurred on an ecological timescale and was triggered by a 2–3-mjump in sea level. Using strictly reliable 230Th ages of corals fromthe upper-reef crest, and improved stratigraphic screening of coral ages fromother stable sites, we constrain this jump to have occurred 121 kyr ago and conclude that it supports an episode of ice-sheet instability during the terminal phase of the last interglacial period. ( English )

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Source Institution:
Florida International University
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