Cryospheric and Polar Processes Seminar
The Potential For Positive Feedback Between West Antarctic Ice Sheet (WAIS) Deglaciation, Decompression-melt-induced Volcanism, And Resultant Sea-level Rise
by Dr. John Behrendt
The West Antarctic Ice Sheet (WAIS) flows through the volcanically active West Antarctic Rift System (WARS); subglacial heat flow is high beneath the WAIS. Aeromagnetic surveys over WAIS have revealed >1000 high-amplitude, shallow source magnetic anomalies indicative of the late Cenozoic – recent age volcanic rocks in the WARS. Satellite altimetry shows rapid retreat of ice shelves bordering WAIS. GRACE satellite data indicate accelerating mass loss from WAIS, reducing basal pressure. Increased volcanic activity resulting from decompression mantle melting beneath a thinning WAIS may serve as a heretofore unexplored positive feedback mechanism that could further destabilize WAIS. In both Iceland, and on midoceanic ridges, dated volcanism suggests that decompression melting of mantle associated with reductions in either ice or water loads can drive significant volcanism. Acceleration of volcanic activity could enhance the rate of loss of WAIS ice, with concomitant rates of rise of global sea level.