The Importance of Icelandic Ice Sheet Growth and Retreat on Mantle CO 2 Flux

John Armitage (1) , David Ferguson (2) , Kenni Petersen (3) , Timothy Creyts (4)

1 IPGP (UMR_7154) - Institut de Physique du Globe de Paris
2 SEE - School of Earth and Environment [Leeds]
3 Aarhus University [Aarhus]
4 LDEO - Lamont-Doherty Earth Observatory

Climate cycles may significantly affect the eruptive behavior of terrestrial volcanoes due to pressure changes caused by glacial loading, which raises the possibility that climate change may modulate CO2 degassing via volcanism. In Iceland, magmatism is likely to have been influenced by glacial activity. To explore if deglaciation therefore impacted CO2 flux, we coupled a model of glacial loading over the last similar to 120 ka to melt generation and transport. We find that a nuanced relationship exists between magmatism and glacial activity. Enhanced CO2 degassing happened prior to the main phase of late-Pleistocene deglaciation, and it is sensitive to the duration of the growth of the ice sheet entering into the Last Glacial Maximum (LGM), as well as the rate of ice loss. Ice sheet growth depresses melting in the upper mantle, creating a delayed pulse of CO2 out-gassing, as the magmatic system recovers from the effects of loading.

Mots clés: SEA-LEVEL; VOLCANISM; RIDGE; DEGLACIATION; SENSITIVITY; THOLEIITES; CALIFORNIA; INVERSION; EMISSIONS; VELOCITY

Domaines: Glaciologie; Climatologie

John Armitage, David Ferguson, Kenni Petersen, Timothy Creyts. The Importance of Icelandic Ice Sheet Growth and Retreat on Mantle CO 2 Flux. Geophysical Research Letters, 2019, 46 (12), pp.6451-6458. ⟨10.1029/2019GL081955⟩. ⟨insu-02919791⟩