Magnetics Business & Technology - November/December 2021 - 30

VISIONS
Antarctica's Magnetic Link to Ancient Neighbors
able data, we only had pieces of the puzzle. Only when we put
them together with satellite magnetic data, can we see the full
picture. "
The resulting combined datasets provide a new tool for the
international scientific community to study the cryptic sub-ice
geology of Antarctica, including its influence on the overlying
ice sheets.
For the first time, an international team of scientists has used
magnetic data from ESA's Swarm satellite mission together
with aeromagnetic data to help reveal the mysteries of the geology
hidden beneath Antarctica's kilometres-thick ice sheets,
and link Antarctica better to its former neighbours.
Not only is Antarctic sub-ice geology important to understand
global supercontinent cycles over billions of years that have
shaped Earth's evolution, it is also pivotal to comprehend how
the solid Earth itself influences the Antarctic ice sheet above it.
The research team from Germany's Kiel University, the British
Antarctic Survey and National Institute of Oceanography and
Applied Geophysics, and Witwatersrand University in South
Africa has today published their findings in the Nature journal
Scientific Reports.
Their new study shows that combining satellite and aeromagnetic
data provides a key missing link to connect Antarctica's
hidden geology with formerly adjacent continents, namely
Australia, India and South Africa - keystones of Gondwana.
The fact that Antarctica is about as remote as you can get
and the land below is covered by a massive ice sheet, makes
collecting geophysical information both challenging and expensive.
Fortunately, satellites orbiting above can see where
humans cannot.
Thanks to magnetic data from the Swarm mission along with
airborne measurements, scientists are paving the way towards
understanding Earth's least accessible continent. This new
research links Antarctica to its ancient neighbours with which
it has shared a long tectonic history - and that needs piecing
together like a jigsaw puzzle.
The team processed aeromagnetic data from aircraft from over
southern Africa, Australia and Antarctica in a consistent manner
with the help of Swarm satellite magnetic data.
Aeromagnetic data do not cover everywhere on Earth, so magnetic
models compiled from Swarm data help to fill the blanks,
especially over India were aeromagnetic data are still not
widely available. Furthermore, satellite data help to homogenise
the airborne data, which were acquired over a period of
more than 60 years with varying accuracy and resolution.
Jörg Ebbing, from Kiel University, explains, " With the availGondwana
was an amalgam of continents that incorporated
South America, Africa, Arabia, Madagascar, India, Australia,
New Zealand and Antarctica. As the tectonic plates collided
in the Precambrian and early Cambrian times some 600-500
million years ago, they built huge mountain ranges comparable
to the modern Himalayas and Alps. This supercontinent started
to breakup in the early Jurassic, about 180 million years ago,
ultimately leaving Antarctica stranded and isolated at the South
Pole, and covered in ice for around 34 million years.
" Using the new magnetic data, our animation illustrates how
the tectonic plates have moved over millions of years after the
breakup of Gondwana, " explains Peter Haas, PhD student at
Kiel University.
Fausto Ferraccioli, Director of Geophysics at the National
Institute of Oceanography and Applied Geophysics in Italy, and
also affiliated with the British Antarctic Survey, said, " We have
been trying to piece together the connections between Antarctica
and other continents for decades. We knew that magnetic
data play a pivotal role because one can peer beneath the
thick Antarctic ice sheet to help extrapolate the geology exposed
along the coast into the continent interior.
" But now we can do
much better, said
Ferraccioli. With
the satellite and
aeromagnetic data
combined, we can
look down deeper
into the crust. Together
with tectonic
plate reconstructions,
we can start
building tantalising
new magnetic
views of the crust
Swarm constellation
to help connect geological and geophysical studies in widely
separated continents. Ancient cratons and orogens in Africa,
India, Australia and East Antarctica are now better connected
magnetically than ever before. "
ESA's Roger Haagmans, said, " This research has been carried
out within ESA's Science for Society 3D Earth study where
we are using gravity data from the GOCE mission and magnetic
data from the Swam mission to understand the structure
and dynamic processes deep within Earth. In this instance,
Swarm's magnetic data have played a starring role. "
For more info: www.esa.int/Applications/ Observing_the_Earth
Swarm
30 Magnetics Business & Technology * November/December 2021
www.MagneticsMag.com
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