Geologists from St. Petersburg (SPbSU), as a member of an international team, has discovered the nature of a large-scale magnetic anomaly in East Antarctica, Naked Science reports. According to their research, the high-amplitude magnetic strip, more than 500 km long, is a “scar” caused by the collision of ancient lithospheric plates.
Antarctica remains the least explored continent, with 98% of its territory hidden under an average layer of ice 2.2 km thick. Until recently, data on the structure of the bedrock (the solid surface of the earth under the ice) was only theoretical, based on remote sensing. In January-February 2026, as part of the Russian-Chinese expedition, scientists were able to carry out targeted ice drilling for the first time and obtain rock samples in the area of the anomaly.
Experts went through 540 meters of ice to retrieve the dark crystalline rock core – mafic grains. Laboratory studies in St. Petersburg, including uranium-lead dating of zircon grains, showed that the rock was formed about 970 million years ago.
Scientists have concluded that it is a piece of an ancient volcanic island arc, “welded” to the mainland during tectonic compression.
As project manager on the Russian side, professor German Leichenkov of St. The anomaly arose during the period of collision between continents and the birth of the supercontinent Rodinia – a hypothetical giant land mass that united nearly all of Earth's continents about a billion years ago, Petersburg explains. Analysis showed that the rock was twice subjected to extreme changes (at temperatures up to 790 degrees and pressures corresponding to depths up to 18 km) – about 890 and 800 million years ago.
The resulting data helps to more accurately reconstruct Earth's appearance during the Precambrian period (the earliest part of the planet's geologic history) and understand modern processes in the ice sheet. The success of the mission confirmed the effectiveness of point drilling based on magnetic maps to study the hidden geology of the pole.
