Evidence of an active volcanic heat source beneath the Pine Island Glacier

• Published in: Nature communications Vol. 9; no. 1; pp. 2431 - 9
• Main Authors: Loose, Brice, Naveira Garabato, Alberto C., Schlosser, Peter, Jenkins, William J., Vaughan, David, Heywood, Karen J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 22-06-2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/58; 704/106/125; 704/2151/598; 704/4111; 704/829/827; Geochemistry; Glaciers; Heat; Helium; Humanities and Social Sciences; Hydrology; Isotope ratios; Land ice; Landforms; Localization; Mantle; Melting; Meltwater; multidisciplinary; Science; Science (multidisciplinary); Sea level; Seawater; Volcanic activity; Volcanoes
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-04421-3

Tectonic landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shelf cavity. The localization of mantle helium to glacial meltwater reveals that volcanic heat induces melt beneath the grounded glacier and feeds the subglacial hydrological network crossing the grounding line. The observed transport of mantle helium out of the Ice Shelf cavity indicates that volcanic heat is supplied to the grounded glacier at a rate of ~ 2500 ± 1700 MW, which is ca. half as large as the active Grimsvötn volcano on Iceland. Our finding of a substantial volcanic heat source beneath a major WAIS glacier highlights the need to understand subglacial volcanism, its hydrologic interaction with the marine margins, and its potential role in the future stability of the WAIS.
The West Antarctic Ice Sheet sits atop an extensional rift system with volcano-like features, yet we do not know if any of these volcanoes are active, because identifying subglacial volcanism remains a challenge. Here, the authors find evidence in helium isotopes that a large volcanic heat source is emanating from beneath the fast-melting Pine Island Ice Glacier.