On the Ice Continent, the polar team of Empress Catherine II Saint Petersburg Mining University is summarizing the first results of its completed fieldwork. Geologists, geophysicists, and drillers begin analyzing their findings while still in Antarctica, then continue during the long journey home, although the main body of scientific interpretation will, of course, take place at the university. A distinctive feature of the 71st Russian Antarctic Expedition (RAE) season was the field validation of the magnetotelluric sounding (MTS) method under the continent’s mining-geological and climatic conditions.
One of the priority areas of the research project “Comprehensive Geological and Geophysical Studies of the Deep Structure of East Antarctica,” supervised by the University’s Rector Vladimir Litvinenko, is metageology.
Given that magnetotelluric sounding (MTS) offers the greatest depth of investigation, it was decided to use it as a mandatory component of the work. The method provides a geophysical section to depths ranging from tens to hundreds of kilometers and makes it possible to analyze the structure of subglacial rocks.
«We are not the first to apply it in this area—our foreign colleagues made an earlier attempt—but not all of the data obtained were of satisfactory quality. The Antarctic region presents challenging conditions that can affect the reliability of the results. For example, the coastal effect can have a strong impact, distorting the nature of geomagnetic variations. A large portion of the signal is absorbed by the ocean. In addition, the glacier’s low electrical conductivity also plays a role. Our university team has synthesized global research experience, identified factors that negatively affect data quality, determined ways to minimize their impact, and brought into the team a magnetotelluric specialist with extensive fieldwork experience in hard-to-access regions of Russia», - noted Alexey Bolshunov, Head of the University’s field team.
The researchers began thinking through grounding conditions and the installation of magnetic sensors while still aboard the icebreaker, as soon as the continent’s coastline came into view. The overland transfer to the station in a Burlak all-terrain vehicle was, in a sense, the first reconnaissance traverse. Although the GPS navigator already contained the planned coordinates for the pilot magnetotelluric work, final adjustments are always made on site. During the transfer, locations were selected for MTS base stations—both on the glacier and in an area where the snow melts in summer, and the basement is exposed. A level site with convenient access was found for test recordings and equipment calibration.
The geophysicists worked alongside the drillers on the Broknes Peninsula, about 10 kilometers from Progress Station. They moved from the station to the drilling site, living in a field module, where the former began experimental and methodological work on magnetotelluric sounding, while the latter focused on assembling the drilling complex.
«In the second half of January, we fully commenced conducting research that will allow obtaining an electrical resistivity section along the coastal segment of the planned Trans-Antarctic profile connecting Progress and Vostok stations, and refining the deep structure of this region of Antarctica. This season, we refined our field methodology for operating in harsh climatic conditions using new Russian-manufactured equipment. Concurrently, we conducted studies to determine how data quality depends on various parameters: the station manufacturer, the type of electrodes, the presence of preamplifiers, recording duration, and weather conditions—wind speed, temperature, snow conditions—as well as the location of the remote base magnetotelluric station.
From late January, blizzards became more frequent, with visibility sometimes remaining under one hundred meters for entire days. We have to be ready—even at night—to head out to work along the profile when the weather improves; its farthest point is about 30 km from our base. Having our own Burlak all-terrain vehicle significantly helps with logistics. At this point, the main phase of fieldwork has been successfully completed; we are processing the data obtained and preparing the equipment for transport», - said Ilya Shuklin, Research Engineer of the NGP “Antarctica”.
«The Mining University team successfully completed its assigned tasks, refined the methodology, and carried out all planned work. It is important to emphasize that these are the first Russian studies in Antarctica using the magnetotelluric sounding method. The use of active electrodes with preamplifiers and extended electric lines to reduce wind-noise correlation between electrodes made it possible to obtain high-quality electromagnetic sounding curves in the frequency range from 1000 to 0.0003 Hz, allowing investigations to depths exceeding 50 km. The quality of field data has a major impact on the final result: all subsequent stages of interpretation and the construction of a geological and geophysical section depend on it. Analysis of the completed studies will help refine the structural and tectonic features of East Antarctica and trace deep faults and supercontinent suture zones», - reported Nina Pokrovskaya, Research Engineer of the NGP “Antarctica”.
During the Antarctic summer, there is a polar day—the sun does not set below the horizon but moves in a circle without rising high. Even in cloudy weather, working on the glacier is possible only with sunglasses and protective sunscreen.
«In general, spending the whole day outdoors is quite pleasant. But there are also periods of severe weather, when the elements do not subside for several days. Because of extremely strong winds and blizzards, even stepping outside the field module can be dangerous—visibility may drop below 100 meters. One must be prepared for such sudden changes in weather and avoid leaving anything light or unsecured outside or on the snow, as it can be blown away or buried under a meter of snow. From the outset, we were prepared to work in difficult conditions, so we tried to complete as much as possible whenever the opportunity arose, without postponing anything until the next day», - Nina Pokrovskaya added.
Once a week, if workload and weather permitted, the team traveled to Progress Station to replenish food supplies and visit the sauna. Although the station is less than 10 kilometers away, the weather there is markedly different. In summer, the coast has almost no snow and far fewer strong winds. Descending from the glacier, one can enjoy new colors, see flocks of birds, and watch curious penguins coming up to investigate. In early February, the first twilight of the season appeared, along with the first sunsets.
«On January 26, the Mining University team had the good fortune to attend Republic Day celebrations at India’s Bharati Station, where they spoke with Indian geologists and geophysicists, learned about their work, and saw how well-equipped the station laboratories are. Our foreign colleagues were very interested in the preliminary results of the Mining University’s studies on the Stornes Peninsula and along the magnetotelluric profile. Events like these are very important because they sustain the spirit of international cooperation and healthy competition», - shared Ilya Shuklin.
Over the course of the field season, the polar researchers also marked several dates important to Russia’s Antarctic explorers: the anniversary of the discovery of Antarctica by the Russian expedition led by Fabian Bellingshausen and Mikhail Lazarev; the 70th anniversary of the opening of the first Soviet Antarctic station, Mirny; and the founding day of Vostok Station, located in the coldest place on Earth.
