IMAGE: A SEISMIC STATION ON THE AUTOR INSTALLED GRASSLAND ICE SHEET. The snow accumulation in one year is ~ 1.5 m, and the solar panels are buried in the snow. SNOW DISTANCE… show more CREDIT: GENTI TOYOKUNI
A team of researchers understands more about the melting of the Greenland ice sheet. They discovered a current of hot stones known as the mantle cloud that rises from the core-mantle boundary below central Greenland and melts the ice from below.
The results of their two-part study were published in the Journal of Geophysical Research.
“Knowledge of the Greenland cloud will improve our understanding of volcanic activity in these regions and the problematic problem of global sea level rise caused by the melting of the Greenland ice sheet,” said Dr. Genti Toyokuni, co-author of the studies.
The North Atlantic region is full of geothermal activity. Iceland and Jan Mayen contain active volcanoes with their own mantle clouds, while Svalbard – a Norwegian archipelago in the Arctic Ocean – is a geothermal area. However, the origin of these activities and their interlinking are largely unexplored.
The research team discovered that the Greenlandic cloud rose from the core-mantle boundary to the mantle transition zone below Greenland. The cloud also has two branches in the lower mantle that flow into other springs in the region and provide heat to the active regions in Iceland and Jan Mayen and the geothermal area in Svalbard.
Their results were based on measurements of the 3D seismic velocity structure of the crust and the entire mantle under these regions. To get the measurements, they used seismic topography. Numerous seismic wave arrival times have been inverted to obtain 3D images of the underground structure. The method works in a similar way to a CT scan of the human body.
Toyokuni was able to use seismographs that he had installed on the Greenland ice sheet as part of the Greenland Ice Sheet Monitoring Network. The project, launched in 2009, envisages collaboration between researchers from 11 countries. The joint team between the USA and Japan is mainly responsible for the construction and maintenance of the three seismic stations on the ice sheet.
Looking ahead, Toyokuni hopes to study the thermal process more closely. “This study gave the bigger picture, so if you examine the feathers at a more local level, you will get more information.”