1400 yr multiproxy record of climate variability from the northern Gulf of Mexico

The Medieval Climate Anomaly and Little Ice Age in Chesapeake Bay and the North Atlantic Ocean

“…The Laurentian Slope temperature record shows similarities to the CB record with a maximum near 800 CE (Fig. 10b), which is consistent with evidence for warm SSTs over the Laurentian Fan from 500 to 900 CE (Keigwin and Pickart, 1999) and in the Gulf of Mexico 600 to 1000 CE (Richey et al, 2007). In contrast, a second deep-water temperature maximum near 1200 CE coincides with cool CB temperature before the onset of a 2°C LIA cooling on the Laurentian slope.…”

Ecological controls on the shell geochemistry of pink and white Globigerinoides ruber in the northern Gulf of Mexico: Implications for paleoceanographic reconstruction

“…The age model for PBBC-1, as well as the oxygen isotope and Mg/Ca records from the white variety of G. ruber, were previously published by Richey et al (2007). Age control is based on seven accelerator mass spectrometer (AMS) radiocarbon dates.…”

“…For each of the box cores the sediment-water interface was recovered, and therefore the core-top samples incorporate the most recently deposited sediments. Radiocarbon dates from a mixed assemblage of planktonic foraminifera, for each of the core-top samples, reflect a modern age (b0 after reservoir correction; Richey et al, 2007Richey et al, , 2009. Size fractions were separated by sieving, and between 2 and 10 different aliquots of ≥60 foraminifera were analyzed for each size fraction of both pink and white G. ruber.…”

Support for global climate reorganization during the “Medieval Climate Anomaly”

“…Other records from the region show a similar pattern of sharp changes or trends near the beginning of the MCA (contemporaneous with the end of the Yucatan droughts) without clear indications at the termination. These include northern Gulf of Mexico SSTs (*1-2°C decline at the onset of the MCA; Richey et al 2007; not shown) and inferred Gulf Stream transport through the Florida Straits (*5-10% decline and increasingly salinity from the onset the MCA into the LIA; Lund et al 2006; not shown). It has been suggested that these changes reflect coupled salinity-transport-climate feedbacks modulating AMOC variability (e.g., Lund et al 2006;Seager et al 2007a, b;Sicre et al 2008a); however, at present the proxy evidence for such an association is quite limited and it is unclear how each of the various elements and processes involved may be linked to each other and to larger-scale MCA-LIA climate changes in general.…”

“…While these records are diverse with respect to interpretation, calibration, sensitivity and resolution, it is now possible to use the more complete proxy network presently in place to attempt qualitative interpretations of linked climate/circulation changes at larger spatial (hemispheric) scales. Some of these more recently available records show distinctive MCA-LIA changes in North Atlantic SSTs and sea ice (Sicre et al 2008a;Massé et al 2008), Meso-American/ Caribbean/Gulf of Mexico climate and oceanic conditions (Haug et al 2003;Lund et al 2006;Richey et al 2007), tropical African rainfall (Verschuren 2004;Verschuren et al 2000;Russel et al 2007;Shanahan et al 2009), and the Indian and East Asian monsoons (von Rad et al 1999;Sinha et al 2007;Zhang et al 2008).…”