(ORDO NEWS) — Japanese scientists have found that a stream of hot rocks beneath central Greenland, known as a mantle plume, rising from the core-mantle boundary, contributes to thermal activity in the region and warming in the Arctic in general. The research results were published in two articles in the Journal of Geophysical Research – Solid Earth.
Geophysicists from Tohoku University analyzed the velocities of seismic waves through the structures of the earth’s crust and mantle in the Greenland region using observation stations located there.
For the measurements, they used the regional seismic tomography method, which works in the Earth in a similar way to computed tomography of the human body. The scientists processed the results and obtained a three-dimensional image of the structure of the subsoil.
The authors discovered a mantle plume beneath Greenland, rising from the core-mantle boundary to the transition zone. The plume has two branches in the lower mantle that separate at a depth of approximately 1,500 kilometers. Closer to the Earth’s surface, they merge with other plumes that provide heat to the active regions of Iceland, Jan Mayen Island and Svalbard.
According to scientists, the North Atlantic region is filled with geothermal activity – Iceland and Jan Mayen have active volcanoes with their mantle magma chambers, and in the west of Spitsbergen there is a “hot” geothermal zone.
Researchers believe that the main Greenland plume channel operates independently of the Icelandic plume, over which Greenland passed 80-20 million years ago, and is associated with the Jan Mayen and Svalbard plumes in the upper mantle, which supply magma to the Jan Mayen hotspot and the Svalbard geothermal zone.
“Knowledge of the Greenland Plume strengthens our understanding of volcanic activity in these regions and the global sea level rise caused by the melting of the Greenland ice sheet,” study leader Dr. Genti Toyokuni of the Department of Geophysics at Tohoku University said in a press release.
Japanese scientists have installed seismographs as part of the Greenland Ice Sheet Monitoring Project, which started in 2009 and involves researchers from 11 countries working at 34 seismic stations. The joint US-Japan group is responsible for the construction and maintenance of three ice sheet stations.
Toyokuni notes that the data from these stations gave a broad picture of the deep structure, which made it possible not only to understand the mechanisms of melting of the Greenland ice sheet, but also to study the reasons for the active geothermal process throughout the Arctic region.
For the first time, scientists have proven that the areas of geothermal activity in the North Atlantic coincide with the zones of low seismic wave propagation velocities that cover the entire lithosphere.
It is known that the melting of the Greenland glaciers is the main reason for the current rise in the level of the World Ocean, which is traditionally associated with global warming.
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