Late-Holocene summer sea-surface temperatures based on a diatom record from the north Icelandic shelf

Diatom assemblages from a high-resolution core on the north Icelandic shelf reveal a general late-Holocene cooling trend, which is interrupted by three relatively warm periods. Diatom data from surface sediments with known modem environmental variables from around Iceland were used as a modem data set for the quantitative reconstruction of summer sea-surface temperatures (SST). The reconstruction is based on a procedure of weighted averaging partial least squares using two components. The reconstructed SST and the water-mass distribution in the area appear to have undergone recurring shifts during at least the last 4600 cal. years. However, the magnitude of changes in the reconstructed SST is relatively small, usually between I and 2degreesC. The general cur-rent pattern has remained the same, although variations in the strength of the cold and warm currents in the area occurred. A comparison with glacier advances in northern Iceland indicates that there is a high degree of correlation between changes in the reconstructed SST on the north Icelandic shelf and the atmospheric circulation above the region.