Integrated aerogeophysical survey in prospecting for copper-nickel deposits in the Far East of Russia

The study aims to demonstrate the capabilities of the modern aerogeophysical survey in prospecting for commercially promising copper-nickel mineralization objects of different types in the Far East of Russia. To realize the aim, innovation survey technologies and physical-geological models of mineralization are used. The set of geophysical methods includes a magnetic survey, gamma-ray spectrometry, and TEM sounding. The key feature of the above set is an electric survey technology that allows registering electrical inhomogeneities of several tens of meters at a depth of the first hundreds of meters. The survey has been conducted on a scale of 1:25 000, for an area of a complex geological structure with prevailing ancient (Archean) rocks. The extremely complex structure of the geophysical fields is a result of the long geological history with pronounced tectonic processes and diverse magmatism. For objective interpretation and localization of the explored objects, different methods of the statistical analysis of the geophysical data are applied, and quantitative interpretation of the magnetic and electrometric fields in the 1-3D format is performed. Based on the obtained aggregate information, volumetric geological mapping has been conducted (up to a 300 m depth), and ore objects of different types have been localized. Eight structure-substance complexes, including ore-bearing basic-ultrabasic and hyperbasic formations, have been distinguished in the study area. The above complexes form two large tectonic blocks with different metallogenic conditions due to the massive intrusion of the main composition, i.e. the source of copper-nickel mineralization. The faults form three systems with markedly different occurrence elements, i.e. pre-ore, syn-mineral (ore controlling) and post-ore. The area is characterized by widely developed mineralized zones of different genesis. Based on the specific geological and geophysical indicators, two ore-controlling complexes of copper-nickel mineralization have been distinguished, i.e. the first type (typical) and the second type (metasomatic). Based on the physical and geological models, ore objects per se have been localized, i.e. associations of ore-controlling formations with specific geophysical characteristics. In total, 12 promising sites have been localized, of which four have been defined as priority ones.

integrated aerogeophysical survey, TEM sounding, sulfide copper-nickel mineralization, survey factors

1. Trigubovich GM, Soloveichik YuG, Royak ME, Chernyshev AV, Persova MG. 3-D Transient electrical survey: theory and practice. In: Geologicheskie aspekty mineral'no-syr'evoi bazy aktsionernoi kompanii “ALROSA”: sovremennoe sostoyanie, perspektivy, resheniya: sbornik trudov konferentsii “Aktual'nye problemy geologicheskoi otrasli Ak "Alrosa" i nauchno-metodicheskoe obespechenie ikh reshenii” = Geological aspects of the Alrosa JSC’s mineral resources base: state-ofthe-art, prospects, and solutions: Conf. collected papers “Present issues in the geological industry of JSC Alrosa, and R&D support”, 31 March – 4 April 2003, Mirny. Mirny; 2003. p.301–311. (In Russ.)

2. Trigubovich GM, Persova MG, Soloveichik YuG. 3-D TEM sounding. Novosibirsk: Nauka; 2009. 217 p. (In Russ.)

3. Kamenetsky FM, Stettler EH, Trigubovich GM. Transients Geo-Electromagnetics. Munich: Ludwig-Maximilian-University of Munich, Vela Verlag; 2010. 304 p.

4. Brodovoi VV, Bortsov VD, Podgornaya LE, et al. Geophysical methods in ore deposit survey. Moscow: Nedra; 1990. 295 p. (In Russ.)

5. Andreev VE, Bobachev AA, Varentsov IvM., Vereshchagina MP., Kulikov VA, Yakovlev AG, et al. Integration of geophysical methods in prospecting for copper-nickel ores at Norilskiy Nikel GMK (ore mining and smelting enterprise). Prospect and Protection of Mineral Resources. 2006;8:71–79. (In Russ.)

6. Kulikov VA, Varentsov IM, Sterligova ID, Solov'eva AV. Evaluation of the electrical resistivity of rich copper-nickel ores of the Norilsk region. Russian Geophysics. 2014;6:25–29. (In Russ.)

7. Mel'nikov AV, Stepanov VA, Gvozdev VI. Strelka ore occurrence as a representative of coppernickel and precious metal mineralization in corniferous basic rocks (Verkhneye Priamurye). Vestnik Amurskogo gosudarstvennogo universiteta = Amursk State University Bulletin. 2007;37:111–116. (In Russ.)

8. Sheka SA. Petrology and ore-bearing capacity of the nickel-bearing dunite-troktolite intrusions of the Stanovoy Ridge. Moscow: Nedra; 1969. 136 p. (In Russ.)

9. Bogatikov OA. Magmatic rocks. Vol. 5. Ultra-basic rocks. Moscow: Nauka; 1988. 508 p. (In Russ.)

10. Stepanov VA. Copper-nickel deposits of the east of Eurasia. Bulletin of Kamchatka Regional Association “Educational-Scientific Center”. Earth Sciences. 2009;1(13):139–148. (In Russ.)