Timing and duration of the Melt-Water Pulse 1A

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Author(s): Deschamps, P.; Durand, N.; Bard, E. G.; Hamelin, B.; Camoin, G.; Thomas, Alex L.; Henderson, Gideon M.; Okuno, J.; Yokoyama, Y.
Author Affiliation(s): Primary:
CEREGE, Aix-En-Provence, France
Oxford University, United Kingdom
University of Tokyo, Japan
Volume Title: AGU 2011 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2011; American Geophysical Union 2011 fall meeting, San Francisco, CA, Dec. 5-9, 2011. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Studying past sea levels provides invaluable information to further our understanding of ice-sheets' response to climate forcing. So far, the most complete and accurate sea-level record that encompassed the period between the Last Glacial Maximum and the present day is based on cores drilled offshore the Barbados coral reef. This record suggests a non-monotonous sea-level rise punctuated by dramatic accelerations, the so-called Melt Water Pulse events, that correspond to massive inputs of continental ice. The most extreme of these events, the MWP1-A, initially identified in the coral-based sea level record from the Barbados island, suggests a sea-level rise of ∼20 meters between 14.1 and 13.6 ka. However, this event remains enigmatic and controversial. The temporal relationship between the MWP1-A and the abrupt climatic events that punctuated the last deglaciation is a subject of controversial debates. Several records are consistent with its occurrence, but no broad agreement emerges about its timing. Finally, large uncertainties surrounding the amplitude and timing of this Melt-Water Pulse 1A have raised doubts about the ice source responsible for such a step in sea-level rise and have questioned its temporal and causal relationships with the Bolling-Older Dryas-Allerod alternance, a major climatic oscillation during the last deglaciation. Consequently, it remains a key issue to fully confirm the existence, timing and amplitude of the MWP-1A by a precise coral reef record. The recent IODP Expedition 310 Tahiti Sea Level offers a unique opportunity to fully confirm the existence, timing and amplitude of the MWP-1A by a precise coral reef record. U-Th ages obtained on shallow to deeper corals collected during the IODP Expedition 310 offshore Tahiti Island extend the previous Tahiti sea-level and allow to document the sea-level rise during the key period of the MWP-1A. Our results confirm the occurrence of an acceleration of the sea-level rise during that period with a 14 to 18 meters amplitude at Tahiti. However, the timing and duration of this event differ significantly from observations from Barbados. These new results indicate that MWP-1A event likely started after 14,650 yr BP and ended before 14,300 yr BP, making it coeval with the Bolling warming. These tight bounds provide conservative constraints on the MWP 1A chronozone. Detailed investigations of the Tahiti record suggest that the MWP 1A event could be even shorter. This could indicate that the rate of the sea-level rise could have largely exceeded 40 mm/yr during this dramatic event.
Year of Publication: 2011
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Allerod; Anthozoa; Antilles; Barbados; Caribbean region; Cenozoic; Climate change; Cnidaria; East Pacific; Expedition 310; Glacial geology; Ice; Ice sheets; Integrated Ocean Drilling Program; Invertebrata; Last glacial maximum; Lesser Antilles; MWP-1A; Melt-Water Pulse 1A; Melting; Pacific Ocean; Pleistocene; Quaternary; Sea ice; Sea-level changes; South Pacific; Southeast Pacific; Tahiti Sea Level Expedition; Transgression; Upper Pleistocene; Upper Weichselian; Weichselian; West Indies
Coordinates: S174600 S172900 W1492400 W1493600
Record ID: 2017050515
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