Abstract
We used a 2.5-dimensional thermomechanical icesheet
model including the oxygen-isotope ratio 18O/16O as a
passive tracer to simulate the isotopic composition (d18O) of
the North American Ice Sheet (NAIS) during the last glacial
cycle. This model allowed us to estimate the NAIS
contribution to the change of seawater d18O (dw) between
the Last Glacial Maximum (LGM) and the Holocene and to
evaluate the effect of nonequilibrium isotopic composition
of the NAIS on the relationship between ice-volume
variations and the ocean isotopic enrichment. The
enrichment due to the NAIS at the LGM was 0.63%,
corresponding to 60% of the LGM sea-level lowstand and
to a mean d18O of the NAIS of approximately 31%. The
modeled NAIS volume variations and the induced dw
changes over the past 120,000 years indicated no significant
time lag. The inaccuracy associated with linearly inferring
ice-volume variations from dw changes was generally less
than 10%.
Original language | Undefined/Unknown |
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Pages (from-to) | L15706/1-L15706/5 |
Number of pages | 5 |
Journal | Geophysical Research Letters |
Volume | 33 |
Publication status | Published - 2006 |