Tuesday, April 18, 2017

Similar Meltwater Contributions to Glacial Sea Level Changes from Antarctic and Northern Ice Sheets

FIGURE 1. Comparison of the Red Sea sea level record with Antarctic and Greenland ice-core records and with the timing of both North Atlantic (Heinrich; H) and Southern Ocean (SA) IRD events.

Eelco J. Rohling, Robert Marsh, Neil C. Wells, Mark Siddall & Neil R. Edwards
Nature 430, 1016-1021(26 August 2004)

Explanation for the above figure:

a. Sea level reconstruction from the Red Sea method (black dots and line) compared with Antarctic ice-core 18O temperature proxy data (grey) from the BYRD-station ice core (80.0° S, 119.5° W). Error bars indicate 1 standard deviation.

b. As a, but for Greenland Ice Sheet Project 2 (GISP2, 72.6° N, 38.5° W) ice-core 18O (grey). Ice-core data as synchronized to the GISP2 timescale using variations in atmospheric methane concentrations10. Red lines represent three-point (about 500-yr) moving averages of the sea level record, which smoothes inter-sample variability within bounds of the 1 interval ( 5.5 m) that applies to the sea level reconstruction13. Red numbers in a indicate magnitudes of increases in sea level according to the smoothed record, whereas black numbers relate to the unsmoothed data. Inverted triangles in b indicate the occurrence of North Atlantic Heinrich Events H4, H5 and tentatively H6, relative to the GISP2 record8. Italic numbers identify main Dansgaard–Oeschger interstadials 8, 12 and 14. Double-headed arrows illustrate dating differences13 between the original correlation of the Red Sea sea level record to BYRD (as in a) and after tuning to a benthic 18O record12.

c. Schematic representation of intervals of IRD, marked by triangles and SA numbers, as well as intervals with negative 18O shifts in planktonic foraminiferal calcite at 41° and 53° S in the South Atlantic sector. These events were placed within our time frame by graphically transferring the positions of the events relative to the GISP2 18O record as originally reported15. Dashed lines indicate possible correlations to the sea level record. A maximum disagreement is suggested of roughly 1,000 yr, which seems reasonable given the inherent uncertainties in both the sea level chronology (b, and ref. 13) and Southern Ocean records. VSMOW, Vienna Standard Mean Ocean Water.

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