The last interglacial as represented in the glaciochemical record from Mount Moulton Blue Ice Area, West Antarctica

Understanding climate during the last interglacial is critical for understanding how modern climate change differs from purely naturally forced climate change. Here we present the first high-resolution ice core record of the last interglacial and transition to the subsequent glacial period from Antarctica and the first glaciochemical record for this period from West Antarctica. Samples were collected from a horizontal ice trench in the Mt. Moulton Blue Ice Area (BIA) in West Antarctica and analyzed for their soluble major anions (Cl−, NO3−, SO42-), major and trace elements (Na, Mg, Ca, Sr, Cd, Cs, Ba, La, Ce, Pr, Pb, Bi, U, As, Al, S, Ti, V, Cr, Mn, Fe, Co, Cu, Zn) and water hydrogen isotopes (δD). The last interglacial is characterized by warmer temperatures (δD), weakened atmospheric circulation (dust elements, seasalts aerosols), decreased sea ice extent (Na, nssSO42-) and decreased oceanic productivity (nssSO42-). A combined examination of Mt. Moulton seasalts, dust, nssSO42- and δD records indicates that the last interglacial was extremely stable compared to glacial age climate events and it ended through a long period of gradual cooling unlike that projected for future Holocene climate.

► First glaciochemical record of the last interglacial from West Antarctica. ► Samples were collected from a horizontal ice trench. ► Water isotope, soluble major anions, major and trace elements analyses. ► The last interglacial was extremely stable compared to glacial age climate events. ► The last interglacial ended through a long period of gradual cooling.