State of Equilibrium of the West Antarctic Inland Ice Sheet

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Science  02 Nov 1973:
Vol. 182, Issue 4111, pp. 476-479
DOI: 10.1126/science.182.4111.476


Data from a traverse connecting Byrd Station, Antarctica, with the local ice divide allow calculation of the mean volume flux at points along the traverse. This is compared with current rates of surface accretion upstream from each point. Near the ice divide the ice sheet seems to be in equilibrium, but near Byrd Station the volume flux is in excess of that needed for ice sheet equilibrium by at least 15 percent. The discrepancy may exist because the traverse does not follow the ice flow exactly or because ice flow at depth is very complex. Although neither of the foregoing possibilities can be disproved, it seems most likely that the discrepancy is due to ice sheet thinning, as has previously been suggested by work on oxygen isotope ratios and temperature in the boreholes at Byrd Station. This thinning probably started at the end of the Wisconsin/Würm glaciation. Causes for the thinning are discussed.