Younger Dryas interval and outflow from the Laurentide ice sheet

A boxmodel of the Great Lakes is used to estimate meltwater flow into the N orth Atlantic between 8000 and 14,000 calendar years B.P. Controls on the m odel include the oxygen isotopic composition of meltwaters and lake waters as measured in the shells of ostracodes. Outflow rates are highest when oxy gen isotopic values of the lake waters are most negative, denoting a maximu m glacial meltwater component. Flow rates reach maximum values before the o nset of the Younger Dryas and after it ends. These maxima appear to be corr elative with the major meltwater pulses MWP 1A and 1B. Although the resumpt ion of North Atlantic Deep Water formation may be tied to the reduction in ice sheet melting, neither the onset nor the end of the Younger Dryas, as r ecorded in the Greenland Ice Sheet Project (GISP2) records, appear tied to maxima in meltwater outflow from the Laurentide ice sheet.