Geologists from Saint Petersburg State University, as part of an international scientific team, analyzed rock data from East Antarctica and determined that the magnetic anomaly in this region resulted from continental collision and the creation of the supercontinent Rodinia approximately one billion years ago.
Antarctica, largely concealed beneath an ice sheet averaging 2.2 kilometers thick, remains one of the least geologically explored areas on our planet. Understanding the structure of its continental crust is vital for reconstructing the history of the formation and breakup of supercontinents—landmasses that united nearly all of Earth’s surface hundreds of millions of years ago. This knowledge may also aid in studying the dynamics and mass balance of the Antarctic ice cover. However, direct data on the geological makeup of Antarctica’s basement rock are virtually nonexistent due to the difficulty in obtaining them and the extreme Antarctic climate.
In January-February 2026, the first-ever ice core drilling project for Antarctic geological research, a joint Russian-Chinese endeavor, successfully retrieved bedrock samples. The drilling targeted the geological origin of a high-amplitude linear magnetic anomaly extending over 500 kilometers parallel to the Antarctic coast. The nature of this anomaly was unknown, though it was hypothesized to be linked to a suture zone between ancient lithospheric blocks. The study’s findings are documented in the scientific journal Polar Science.
During the fieldwork, utilizing previously conducted detailed magnetic and radar surveys, scientists drilled through more than 540 meters of ice to obtain a core sample of the bedrock. These represent the first geological specimens recovered from beneath the East Antarctic ice for solving specific geological questions.
Following the transportation of the retrieved samples from Antarctica to St. Petersburg, they underwent laboratory analysis using state-of-the-art research methods. Specialists conducted petrographic, chemical, and isotopic analyses, along with uranium-lead dating, on the zircon grains found within the rock. This comprehensive approach allowed for precise determination of not only the rock’s composition but also the age boundaries of its formation and subsequent metamorphic alterations, ultimately clarifying the nature of the magnetic anomaly.
“Through the drilling, we obtained a sample of a dark crystalline rock—a mafic granulite. The investigation confirmed that this specific rock is the source of the intense magnetic anomaly observed at the surface. The data suggest an important conclusion: this anomaly is a remnant of an ancient island volcanic arc that was incorporated into the Antarctic continent in the distant past. This incorporation was part of the massive continental collision event that led to the formation of the supercontinent Rodinia about a billion years ago,” explained Professor German Leichenkov of the SPbU Department of Geophysics, who headed the project on the Russian side.
The authors determined that the rock’s initial magmatic precursor crystallized around 970 million years ago. Subsequently, the rock underwent two significant transformations due to high temperatures and pressure: around 890 million and 800 million years ago, occurring under conditions ranging from 790 to 650 degrees Celsius and pressures equivalent to depths of 18–15 kilometers within the Earth.
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