Two new studies published in the Journal of Geophysical Research recently provide the newest update on the state of Greenland’s melting ice sheet. The research points toward the discovery of a mantle plume beneath the landmass that is effectively melting much of the ice sheet from beneath the land.
"Knowledge about the Greenland plume will bolster our understanding of volcanic activities in these regions and the problematic issue of global sea-level rising caused by the melting of the Greenland ice sheet," said Dr. Genti Toyokuni, who co-authored the studies.
While the North Atlantic is known for its robust geothermal activity, there is still much unknown about the region’s seismology. To better understand what was going on beneath the surface, Dr. Toyokuni and colleagues used seismic topography methods to gather measurements of the 3-D seismic velocity structure of the crust and mantle.
The team relied on the data collected from seismographs from the 2009 Greenland Ice Sheet Monitoring Network, an international project devised to observe Greenland’s ice sheet. Now with over a decade of data from the seismographs, Dr. Toyokuni was able to convert the information of observed seismic waves to produce 3-D images of the underground structure. The scientists explain that the process is similar to that of how a CT scan takes images.
These images showed that the Greenland plume reaches from the core-mantle boundary to the mantle zone below Greenland. The hot, molten rock of the plume extends in two branches to reach the lower mantle where it connects with other plumes, creating a network that carries geothermal heat to the region as far as Iceland, Jan Mayen, and Svalbard.
Dr. Toyokuni plans to continue this investigation in order to quantify how the geothermal heat from the plume is affecting the melting of the ice sheet. "This study revealed the larger picture, so examining the plumes at a more localized level will reveal more information," concludes Toyokuni.