NOAA/WDS Paleoclimatology - Schmidt et al. 2006 W. Caribbean Mg/Ca, d18O Data and SST Reconstruction

Mg/Ca ratios in the planktonic foraminifera Globigerinoides ruber from
Colombian Basin core ODP 999A suggest that Caribbean sea surface temperatures
(SSTs) were from 2.1 to 2.7°C colder than the present during the last three
glacial maximums. In comparison, faunal derived SSTs (SIMMAX method) show that
August SSTs in the Caribbean varied <2°C over the past 360 kyr, whereas
February SSTs varied between 21.0°C and 26.5°C. Changes in the Mg/Ca-SST record
contain a strong 23 kyr periodicity, suggesting the Mg/Ca-SST record reflects
a warm season weighted SST average rather than an annual mean SST. Combining
several dissolution indices, we identify brief periods of decreased carbonate
preservation in our record and show that MIS 11 stands out as the most intensive
dissolution cycle in the Caribbean over the last 460 kyr. Comparison of Caribbean
SST change with a similar estimate of tropical SST variability in the western
Pacific over the past 360 kyr reveals shifts in the east-west tropical SST gradient
that are coeval with glacial-interglacial climate change and consistent both with
a southward migration of the glacial ITCZ and with a glacial El Niño-like mode of
tropical circulation.