The Moscow School of Russian Airborne Geophysics

The development of the Moscow school of Russian airborne geophysics is directly linked to the establishment and development of this field at the State Research and Production Enterprise Aerogeofizika. From 1970, it operated as a specialized airborne geophysical unit within various organizations of the USSR Ministry of Geology; in 1992, it was established as an independent state-administered entity by order of the Committee for Geology and Subsoil Use under the Government of the Russian Federation.

The development of GNPP Aerogeofizika over more than 25 years was largely shaped by its commitment to rapidly introducing the latest domestic and international advances in instrumentation, computer hardware and technology, as well as by its own research and development in these and other fields. GNPP Aerogeofizika was the first in the country’s airborne geophysical practice to introduce digital recording of airborne geophysical data (1974), a Doppler-based active helicopter navigation system (1981), and a satellite navigation system (1991). GNPP Aerogeofizika improves and develops new airborne geophysical methods and new types of airborne geophysical equipment. The application of new technologies in airborne surveys over large areas has itself enabled, and continues to enable, results of major importance to the national economy.

Work for geological purposes began in 1971. Integrated airborne geophysical exploration (magnetometry, gamma-ray spectrometry and airborne electromagnetic surveying) at scales of 1:25000 and 1:50000, with ground investigation and verification of anomalies to discover economic bauxite deposits, continued through 1978. It covered Central, Northern and Southern Timan and the western and eastern slopes of the Northern, Subpolar and Polar Urals, with a total surveyed area of approximately 40 thousand km². The primary objective was to develop an efficient, rapid exploration technology for economic bauxite deposits suited to the conditions in these areas.

These investigations identified a new bauxite-bearing district in the Timan–Pechora region; substantially increased the reserves of the Central Timan bauxite deposits; discovered the Natalovskoye high-grade bauxite deposit in the Ivdel district of the Northern Urals; increased inferred bauxite resources in the Kara area of the Polar Urals; and identified non-economic mineral occurrences in other areas. In 1977, three local magnetic anomalies were also identified in Central Timan, subsequently proving to be the first kimberlite pipes discovered in the northern Russian Platform. In addition to the assigned work, anomalies and anomalous areas prospective for economic mineralization (gold, platinum and polymetallic ores) were delineated.

At the same time, ground geophysical exploration methods using seismic data were being improved: areas prospective for bauxite were delineated, and the widespread occurrence of thick blanket weathering profiles containing rich, weakly magnetic iron ores in the Belgorod region (Kursk Magnetic Anomaly) was demonstrated for the first time. Drilling confirmed the prediction, leading to the discovery of the unique Razumenskoye iron ore deposit.

From 1979 to 1988, Aerogeofizika conducted integrated airborne geophysical exploration for diamond deposits (magnetometry, gamma-ray spectrometry and airborne electromagnetic surveying) at scales of 1:10000, 1:25000 and 1:50000, with ground investigation and verification of anomalies in the Arkhangelsk region and western Yakutia. Approximately 200 thousand line-km of airborne surveys were completed at various scales. Here too, the initial stage involved refining technologies for targeted airborne geophysical exploration for diamond deposits.

Drilling within an identified local magnetic anomaly in the Zimneberezhny district of the Arkhangelsk region resulted in the discovery of an economic diamond deposit. Overall, GNPP Aerogeofizika, together with other enterprises, participated in the discovery of the Lomonosov diamond deposit and other kimberlite bodies in the Arkhangelsk region. R.S. Kontarovich (then a field-party leader) received the “Discoverer of a Deposit” diploma and badge. A prospectivity map for primary diamond deposits in the Malo-Botuobinsky district of western Yakutia was compiled and delivered to local organizations in 1982; with minor refinements, it remains the principal map for exploration in the district to this day. Prospectivity was confirmed at several sites: new dispersion halos of pyrope, picroilmenite and kimberlite fragments were identified. Ground geophysical methods for verifying prospective areas and anomalies were improved. Introducing one of these methods—cross-hole radiowave transmission—enabled the Amakinskaya Expedition to discover six new kimberlite pipes in Yakutia.

From 1975 to 1985, substantial investigations (approximately 20 thousand km²) were conducted in exploration for gold and silver deposits. Airborne geophysical exploration and airborne geophysical surveys (magnetometry and gamma-ray spectrometry) at scales of 1:25000 and 1:50000, with ground investigation and verification of anomalies (the latter only in exploration areas), were undertaken in Central Asia, the Magadan region, Transbaikalia, Primorsky Krai and Chukotka. In virtually all surveyed territories, the potential of known gold deposits was expanded and new ore-prospective areas and sites were delineated.

Overall, the period from 1971 to 1985 produced the greatest number of concrete, positive geological results. It should be emphasized that the work at that time consisted mainly of airborne geophysical exploration, which included targeted predictive interpretation of the data and substantial ground verification work in addition to airborne surveys.

From the second half of the 1980s to the present, Aerogeofizika has concentrated its efforts primarily on airborne geophysical surveys themselves, in support of geological mapping and exploration, in accordance with client requirements.

To provide a detailed, high-accuracy geophysical basis for geological mapping, integrated and single-method airborne geophysical surveys (magnetometry, gamma-ray spectrometry and electromagnetic surveying) at scales of 1:25000 and 1:50000 have been completed over approximately 90 thousand km² and remain ongoing in the Moscow, Ryazan, Tula and Kaluga regions of the Russian Federation from 1993 to the present.

In 1979–1990, integrated airborne geophysical surveys (magnetometry, gamma-ray spectrometry and electromagnetic surveying) at scales of 1:25000, 1:50000, 1:100 000 and 1:200 000 were completed in central and northern Mongolia and in Cuba, covering approximately 350 thousand km² in total. The management of the Soviet Geological Expedition in the Mongolian People’s Republic (Ulaanbaatar) commended the high methodological and technical standard of the work, its geological effectiveness, the professional competence of the team’s specialists, and their substantial contribution to developing Mongolia’s mineral resource base.

Since 1995, GNPP Aerogeofizika has participated in airborne geophysical support for a regional reference profile for deep mapping (magnetic surveying and gamma-ray spectrometry) along the Kandalaksha–Kem–Petrozavodsk–Novgorod–Velikiye Luki route: 11 parallel lines spaced 2 km apart and 1 line at an altitude of 3 km, totalling 12000 line-km.

From 1988 to the present, airborne geophysical surveys (magnetometry, gamma-ray spectrometry and, occasionally, airborne electromagnetic surveying) at scales of 1:25000, 1:50 000 and 1:100 000 have supported exploration over a total area of approximately 60 thousand km². They covered the Bryansk, Kaluga and Smolensk regions of the Russian Federation (diamonds), the Kostroma region (gold), the Norilsk district (copper), Novaya Zemlya (copper), the northern Cis-Urals and the Republic of Tatarstan (oil). In all cases, clients received geophysical field maps and interpretation maps incorporating predictive elements.

From 1982 to the present, addressing environmental and engineering problems has been the second most important area of GNPP Aerogeofizika’s activities.

In June 1986, a special airborne geophysical team led by A.A. Ursov was placed at the disposal of the Government Commission for Mitigating the Consequences of the Chernobyl Nuclear Power Plant Accident. Maps of radionuclide contamination were produced within a very short time for virtually all of Ukraine and Moldova, and for many regions of Russia and Belarus. The results were highly rated by the interdepartmental expert scientific and technical commission of Goskomgidromet, the lead organization responsible for implementing the State Programme. Several participants received state awards.

The State Programme for radiation mapping was completed for areas contaminated by accidents at the Mayak facility in the Chelyabinsk and Sverdlovsk regions and at Krasnoyarsk-26, and by tests at the Novaya Zemlya and Semipalatinsk test sites. The resulting information made it possible to assess contamination by artificial (Cs-137, Co-60, etc.) and natural (U, Th, K) radionuclides, and to identify areas requiring environmental protection measures;

GNPP Aerogeofizika participated in compiling the Atlas of Radioactive Contamination of the Country, incorporating the results of gamma-ray spectrometric investigations. Work on the Atlas addressed several major scientific and applied problems: a method was developed and tested to determine the Cs-137 inventory in the soil layer while accounting for its depth distribution; a set of algorithms and programs was developed to identify any gamma emitters in a combined spectrum without prior information on its spectral composition; a method and software were developed to account for the contribution of “free” radon-222 to uranium concentration measurements without an additional “radon” detector; and a method was implemented to reconstruct the gamma radiation dose rate at the time of nuclear tests. Comparable scientific and applied work had not previously been undertaken anywhere in the world. The results were published and presented at international conferences.

A number of point sources of ionizing radiation were identified in Moscow and the Moscow region, around Noginsk, Elektrostal, the settlement of Remmash and elsewhere. Coordinates of ground contamination by Cs-137 were passed to the Moscow Region Civil Defence and Emergency Situations Headquarters. Reconnaissance at the indicated location revealed an area of radioactive contamination with an exposure rate exceeding 3000 µR/h.

In 1988, the USSR Ministry of Geology sent an aerial survey team from GNPP Aerogeofizika (A.A. Ursov) to Armenia to work in the Spitak earthquake zone. The airborne geophysical survey yielded a favourable assessment of the condition of the nuclear power plant in the earthquake area, while also showing that insufficient attention had been paid to the tectonic structure of the selected site during plant design and siting. The team promptly completed all its assigned tasks, earning high praise from the Armenian leadership and the USSR Government.

Remote monitoring of urban agglomerations and engineering structures to address environmental and municipal utility issues is currently a major area of GNPP Aerogeofizika’s activities.

For 13 years, heating network condition assessments using airborne thermal infrared imaging (TIKAS) have been commissioned by enterprises of the Fuel and Energy Administration and municipal services in Moscow, Tula, Lipetsk, Kyiv, Minsk, Baku, Ryazan, Kaliningrad in the Moscow region, Lyubertsy, Reutov, Elektrostal and other cities. Thermal monitoring surveys are performed twice a year, at the beginning and end of the heating season. This enables rapid assessment of underground heating networks, identification of sections approaching failure or already in an emergency condition, and refinement of network layout maps. TIKAS data provide the basis for planning and updating emergency and scheduled repairs. For example, in 1995, GNPP Aerogeofizika specialists surveyed approximately 900 km² in Moscow. According to just one client, the economic benefit of the aerial survey amounted to 450 million rubles.

For several years, thermal surveys were conducted to locate industrial and municipal wastewater discharges into river networks, alongside investigations to assess the condition of paved road surfaces.

Airborne aerosol surveys were completed over the major industrial centres of Moscow, Norilsk and Tula. They identified persistent atmospheric geochemical dispersion halos for more than 20 chemical elements that pollute the air. Elevated cadmium concentrations near the Ostankino television tower were detected for the first time. Vertical distribution measurements of nitrogen dioxide, sulfur dioxide and atmospheric aerosols were made at the Ostankino television tower for the first time, providing unique information on how gas concentrations vary with height.

This brief review of work completed over more than a quarter-century of GNPP Aerogeofizika’s history shows that the Moscow school of airborne geophysics developed while participating in the development and improvement of technologies for solving a wide range of problems. It has accumulated unique airborne geophysical technologies and data processing and interpretation technologies, and possesses the most comprehensive and up-to-date fleet of airborne geophysical equipment in the Russian Federation, which it continually expands and improves. The high geological and economic effectiveness of this work is a natural outcome of the efforts of Moscow’s airborne geophysicists.