Scientists from Germany’s Kiel University and British Antarctic Survey (BAS) reveal how the European Space Agency (ESA) Gravity field and Ocean Circulation Explorer (GOCE) mission is helping to unveil deep geological features of the Earth’s lithosphere and tectonic plates in a relatively simple way.
Publishing this week in the journal Scientific Reports the researchers say that the study is also a step forward in their quest to understand how the continental structure beneath Antarctica influences the behaviour of ice sheets - research that is important for assessing the frozen continent’s contribution to future sea-level rise.
The team analysed satellite-derived gravity datasets from the GOCE mission to provide a new tool to study the structure of all Earth’s continents, including Antarctica. Different gravity gradient fields were combined into simpler ‘curvature images’ that can now be interpreted to reveal a large-scale tectonic map of the Earth.
Lead author, Prof. Jörg Ebbing from the Kiel University said: “Our new satellite gravity gradient images improve our knowledge of Earth’s deep structure. The satellite gravity data can be combined with seismological data to produce more consistent images of the crust and upper mantle in 3D, which is crucial to understand how plate tectonics and deep mantle dynamics interact.”
Fausto Ferraccioli, Science Leader of Geology and Geophysics at the British Antarctic Survey and co-author of the study, said: “Satellite gravity data are revolutionizing our ability to study the least understood continent on Earth, Antarctica. These gravity images provide tantalising insights, and allow us to probe deep into the Earth’s interior. We can now glimpse ancient parts of the Earth’s continental crust. In East Antarctica, we see an exciting mosaic of geological features that reveal fundamental similarities and differences between the crust beneath Antarctica and other continents that it was joined to until 160 million years ago.”
The new study presents a view of the Earth’s continental crust and its uppermost mantle not previously achievable using global seismic models alone. The authors noted that, despite their similar seismic characteristics, there were contrasts in the gravity signatures for ancient parts of the crust (known as cratons), indicating differences in their deep structure and composition. These features are important. Because they form the oldest cores of the continental lithosphere, they hold key records of Earth’s enigmatic early history.
Shape index for Antarctica in a Gondwana supercontinent plate reconstruction since ca 200 Ma ago. The new satellite gravity data help study the Antarctic lithosphere and its former links with Africa, India, Australia, Zealandia and South America.
Ebbing, J., Haas, P., Ferraccioli, F., Pappa, F., Szwillus W., and Bouman J. Earth tectonics as seen by GOCE - Enhanced satellite gravity gradient imaging. Scientific Reports, DOI: 10.1038/s41598-018-34733-9. www.nature.com/articles/s41598-018-34733-9
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