The influence of Antarctic subglacial volcanism on the global iron cycle during the Last Glacial Maximum

Silvia Frisia (1) , Laura S. Weyrich (2) , John Hellstrom (3) , Andrea Borsato (1) , Nicholas R. Golledge (4, 5) , Alexandre M. Anesio (6) , Petra Bajo (7) , Russell N. Drysdale (7, 8) , Paul C. Augustinus (9) , Camille Rivard (10) , Alan Cooper (2)

1 Univ Newcastle, Sch Environm & Life Sci, Callaghan, NSW 2308, Australia
2 University of Adelaide
3 Univ Melbourne, Sch Earth Sci, Parkville, Vic 3010, Australia
4 GNS Science
5 Victoria Univ Wellington, Antarctic Res Ctr, Wellington 6140, New Zealand
6 University of Bristol [Bristol]
7 Univ Melbourne, Sch Geog, Parkville, Vic 3010, Australia
8 EDYTEM - Environnements, Dynamiques et Territoires de Montagne
9 Univ Auckland, Sch Environm, Auckland 92019, New Zealand
10 ESRF - European Synchrotron Radiation Facility

Marine sediment records suggest that episodes of major atmospheric CO2 drawdown during the last glacial period were linked to iron (Fe) fertilization of subantarctic surface waters. The principal source of this Fe is thought to be dust transported from southern mid-latitude deserts. However, uncertainty exists over contributions to CO2 sequestration from complementary Fe sources, such as the Antarctic ice sheet, due to the difficulty of locating and interrogating suitable archives that have the potential to preserve such information. Here we present petrographic, geochemical and microbial DNA evidence preserved in precisely dated subglacial calcites from close to the East Antarctic Ice-Sheet margin, which together suggest that volcanically-induced drainage of Fe-rich waters during the Last Glacial Maximum could have reached the Southern Ocean. Our results support a significant contribution of Antarctic volcanism to subglacial transport and delivery of nutrients with implications on ocean productivity at peak glacial conditions

Domaines: Sciences de la Terre; Sciences de l'environnement

Silvia Frisia, Laura S. Weyrich, John Hellstrom, Andrea Borsato, Nicholas R. Golledge, et al.. The influence of Antarctic subglacial volcanism on the global iron cycle during the Last Glacial Maximum. Nature Communications, 2017, 8, 9 p. ⟨10.1038/ncomms15425⟩. ⟨hal-01692159⟩