A Mysterious Anomaly in Antarctica Turned Out to Be the Trace of an Ancient Catastrophe, SPbGU Scientists Found

SPbGU geologists analyzed rock samples from East Antarctica and determined the nature of a mysterious magnetic anomaly that had puzzled scientists for decades. It turned out to be linked to an ancient continental collision and the birth of the supercontinent Rodinia about a billion years ago.

SPbGU expedition in East Antarctica
Image source SPbGU

Antarctica is one of the most inaccessible regions on the planet: almost all of it is hidden beneath an ice sheet averaging 2.2 km in thickness. There is extremely little direct data on the structure of the bedrock below. However, in January-February 2026, Russian and Chinese scientists for the first time drilled the ice to a depth of more than 540 meters and reached the rocky formations beneath it. The core was studied in St. Petersburg using modern methods: petrography, chemical and isotopic analysis, as well as uranium-lead dating of zircons.

As a result of the drilling, we obtained a sample of a dark crystalline rock - the so-called mafic granulite. The study showed that this very material is the source of the intense magnetic anomaly that we observe at the surface. The data obtained allow us to draw an important conclusion: this anomaly is a fragment of an ancient island volcanic arc that in the distant past \"joined\" the Antarctic continent. This process was part of a large-scale collision of continents and the formation of the supercontinent Rodinia about a billion years ago.

German Leychenkov, Professor of the Department of Geophysics, SPbGU

Core taken from beneath the ice during the expedition
Image source SPbGU

The scientists established that the primary igneous rock formed about 970 million years ago. It was then twice subjected to major changes under the influence of high temperatures (up to 790 degrees) and pressure corresponding to a depth of 15-18 km - this happened approximately 890 and 800 million years ago.