Description
Working with seabed sediment sub-cores taken from a giant gravity core (59GGC) and a multicore (MC22) separated from each other by 22 km along the Carolina Slope of the western North Atlantic Ocean near the southern flank of the Gulf Stream at 32.977°N, 76.316°W and 32.784°N, 76.276°W, respectively, Saenger et al. developed two sets of 2000-year sea surface temperature (SST) histories based on Mg/Ca ratios of the shells of the planktic foraminifera Globigerinoides ruber, using two different Mg/Ca-SST calibrations: that of Anand et al. (2003) for both cores and that of Arbuszewski et al. (2010) for the 59GGC core only.

Using the calibration of Anand et al., the peak warmth of the MWP is seen to have been about 0.1°C less than that of the CWP based on both the 59GGC and MC22 core data; while using the calibration of Arbuszewski et al. (2010), the peak warmth of the MWP is seen to have been about 0.7°C greater than that of the CWP based on the data from the 59GGC core, which was the only one for which the authors presented Arbuszewski et al. calibration results. Thus, for both sites (two independent results for two locations), Saenger et al.'s study suggests that the peak warmth of the MWP was 0.1°C less than that of the CWP, while it also suggests that the peak warmth of the MWP was 0.7°C greater than that of the CWP at the 59GGC site, with the MWP of both sites falling in the range of about AD 700-1300.

Arbuszewski, J., deMenocal, P., Kaplan, A. and Farmer, E.C. 2010. On the fidelity of shell-derived δ¹⁸O_seawater estimates. Earth and Planetary Science Letters 300: 185-196.