Antarctica has a 'gravity hole' where sea levels are 420ft lower

"The vast gravity hole, known as the Antarctic Geoid Low (AGL), is the product of incredibly slow rock movements, according to the experts. Starting 70 million years ago - a time while dinosaurs still roamed the Earth - less-dense rock built up beneath the frozen continent and weakened the pull of gravity. The gravity hole started small before rapidly growing in strength between 50 and 30 million years ago - creating the strange ocean dip that we see today."

"When astronauts on the International Space Station look down on Earth, it might look like a smooth blue marble. However, in reality, our planet is shaped a bit more like a 'bumpy potato'. This lumpy surface is due to areas of non-uniform gravity, caused by the uneven distribution of material beneath the surface. In regions where hot rock from within the Earth's mantle rises towards the surface, the lower density of rock means that gravity is weaker."

"Since the 1940s, scientists have known that these gravitational anomalies cause deep depressions across large areas of the ocean. However, figuring out how and why these gravitational anomalies form hundreds of miles beneath the surface is much harder. To map how the Antarctic gravity hole formed, the researchers combined earthquake recordings from around the world with a computer model of the planet."

Gravity varies across Earth's surface, producing regions of weaker pull that cause ocean surfaces to dip toward stronger-gravity areas. The Antarctic Geoid Low (AGL) in the Ross Sea produces a sea-level depression about 420 feet (130 m) below surrounding water. The AGL developed as less-dense mantle rock accumulated beneath Antarctica beginning around 70 million years ago, weakening gravity locally. The anomaly expanded rapidly between about 50 and 30 million years ago, deepening the ocean dip. Mantle upwellings and uneven subsurface material distributions produce the planet's irregular geoid. Seismic data combined with computer models can map the deep mantle processes that formed the gravity hole.

Read at Mail Online