Cyles we combine mgca measurements a proxy for the

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cyles, we combine Mg/Ca measurements (a proxy for the temperature of calcification) with d18O analyses of shells from the surface-dwelling foraminifera Globigerinoides ruber from ODP site 1060 located beneath the Gulf Stream on the Blake Outer Ridge (36.77&Mac251;N, 74.47&Mac251;W; 3480 m; 20-53 cm/kyr sed. rate) to produce a high- resolution record of δ 18 O SEAWATER ( δ 18 O SW ) during MIS 3 (49.5 – 59.2 kyr). The Mg/Ca-temperature (SST) record from 1060 shows minimal variability (±3&Mac251;C) between stadials and interstadials. Average interstadial Mg/Ca-SSTs (25.2&Mac251;C) agree with faunal August SST reconstructions(Vautravers and Shackleton, 2004), but stadial Mg/Ca-SST reconstructions are several degrees warmer than faunal estimates. The calculated δ 18 O SW record covaries with Greenland ice core δ 18 O values (Johnsen et al., 2001), and indicate high salinities similar to coeval Caribbean salinity reconstructions(Schmidt et al., 2004) during stadials followed by abrupt decreases up to 0.9‰ occurring in less than 250 years on the transition to interstadials. We hypothesize that the input of isotopically light melt water from the southeast coast of North America due to continental ice sheet retreat during interstadials accounts for the rapid and large decrease in Gulf Stream salinity. Covariation between our δ 18 O SW record and the Greenland ice core δ 18 O record suggests that glacial Gulf Stream salinity is sensitive to D-O cycles, increasing during stadials and rapidly decreasing in response to Northern Hemisphere warming.
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