Geological research in prospecting for diamond deposits
Abstract
Introduction: Among more than 5000 kimberlite diatremes and dykes on the Earth, at least 500 original diamond-bearing structures were found. The effectiveness of the Schlich-mineralogical method of prospecting for new diamond deposits is complicated in the areas with thick sedimentary strata. Therefore, the need for the use of a combination of geological and geophysical research becomes the most important factor when solving forecasting and prospecting problems. Methodology and research efforts: The Schlich-mineralogical method is not very effective in the forecasting of and prospecting for new kimberlite fields and pipes as it is impossible to perform detailed paleogeographic reconstructions due to the insufficient and fragmentary initial geological information. The study of kimberlite magmatism usually requires the use of tectonic and geophysical data on the structure of the section-composing strata and their mineralogical and petrophysical characteristics as well as a comprehensive study of pipe kimberlites and the deep rock xenoliths contained in them. Tectonic, geophysical, space, and historical-mineragenic are the main types of research needed for the geological study of diamond-promising areas. The main geological and tectonic research methods are regional geological and geophysical works. They include a wide range of seismic, gravimetric, magnetometric, and electrical exploration works as well as crosshole tests with various approaches and variations depending on the specific structure of the promising areas. Their methodology involving the use of a large amount of data, including the author’s data, and is based on the diamond potential of the Siberian and East European platforms. These are the leading methods for covered areas where scattering halos of kimberlite minerals have been repeatedly redeposited and detached from their primary sources. Results and discussion: We studied the tectonic history of diamond-bearing magmatism by eight main productive Paleogene and Neogene epochs: Pre-Riphean, Riphean, Early Paleozoic (Caledonian), Middle Devonian – Early Carboniferous (Early Hercynian), Middle Carboniferous – Middle Triassic (Late Hercynian), Late Triassic – Jurassic (Cimmerian), Cretaceous (Early Alpine), and Paleogene – Neogene (Late Alpine). Kimberlite fields with or without diamond-bearing diatremes, dykes, veins, and subtabular deposits are associated with thermoblemes. These fields, which are of all ages on ancient platforms, are affected by lineament rifts of Riphean and Phanerozoic aulacogenes. Kimberlite bodies are inclined towards low-amplitude tectonic disturbances, including those in the peripheral parts of aulacogens. Analysis of the factual data allowed recommending a prospecting strategy for primary diamond deposits at the level of kimberlite fields for both the Siberian and East European platforms as well as other ancient platforms of the world. The standard rational geological and geophysical complex should be used only within the orthocratons. The goal of the system for forecasting geological and geophysical research is to determine the thermoblemes within any given orthocratons which are preliminarily determined based on the maps of gravitational and magnetic fields. The geological and geophysical data is studied in order to discover the signs of lineament rifts crossing thermoblemes. In case of a positive result, structural mapping of the thermobleme area will be required using structural drilling, GIS, and shallow seismic exploration, which will allow mapping the disturbances as well. The obtained structural map will allow outlining the kimberlite field, and in the future its structural elements will become the basis for the selection of specific promising areas for prospecting for kimberlite bodies. Conclusion: The areas of kimberlite magmatism should be considered the most realistic sites for the assessment of the diamond potential of new areas. They are complex radial ring structures of “local” genesis consistently located at the intersection nodes of riftogens that are inherently developing along the elements of planetary and regional radial concentric systems. Such areas emerged due to the relatively small mantle diapirs whose place of penetration into the earth’s crust was prepared by all the previous tectonic events. Magmatic and fluid eliminations of these formations predetermined the exposure of kimberlites with diamonds to the earth’s surface. It is recommended to prospect for kimberlite and lamproite fields only within the areas where they are localised in the sections with a standard set of structural factors. The latter are determined by regional geological studies. The use of space, historical-mineragenic, and geophysical research is highly important in this case.
Downloads
References
2. Serokurov Yu. N., Kalmykov V. D., Zuev V. M. Kosmicheskie metody pri prognozirovanii i poiskakh mestorozhdenii almazov [Cosmic methods in forecasting and prospecting for diamond deposits]. Moscow, Nedra publ., 2001, 198 p. (In Russ.)
3. Afanas'ev V. P., Zinchuk N. N., Koptil' V. I. Poligenez almazov v svyazi s problemoi korennykh rossypei severo-vostoka Sibirskoi platform [Polygenesis of diamonds in connection with the problem of bedrock placers in the north-east of the Siberian platform]. Doklady Akademii nauk – Reports of the Academy of Sciences, 1998, vol. 361, no. 3, pp. 366–369. (In Russ.)
4. Khar'kiv A. D., Zuenko V. V., Zinchuk N. N., Kryuchkov A. I., Ukhanov A. V., Bogatykh M. M. Petrokhimiya kimberlitov [Petrochemistry of kimberlites]. Moscow: Nedra publ., 1991, 304 p. (In Russ.)
5. Zinchuk N. N. Sravnitel'naya kharakteristika veshchestvennogo sostava kory vyvetrivaniya kimberlitovykh porod Sibirskoi i Vostochno-Evropeiskoi platform [Comparative characteristics of the material composition of the weathering crust of kimberlite rocks of the
Siberian and East European platforms]. Geologiya i geofizika – Geology and geophysics, 1992, no. 7, pp. 99–109. (In Russ.)
6. Kotel'nikov D. D., Dombrovskaya Zh. V., Zinchuk N. N. Osnovnye zakonomernosti vyvetrivaniya silikatnykh porod razlichnogo khimicheskogo i mineralogicheskogo tipa [Basic laws of weathering of silicate rocks of various chemical and mineralogical types]. Lithol-
ogy and Mineral Resources – Litologiya i poleznye iskopaemye, 1995, No. 6, pp. 594–601. (In Russ.)
7. Kotel'nikov D. D., Zinchuk N. N. Tipomorfnye osobennosti i paleogeograficheskoe znachenie slyudistykh mineralov [Typomorphic features and paleogeographic significance of micaceous minerals]. Izvestiya VUZov. Geologiya i razvedka – Proceedings of higher educational establishments. Geology and Exploration, 1996, no. 1, pp. 53–61. (In Russ.)
8. Gladkov A. S., Bornyakov S. A., Manakov A. V., Matrosov V. A. Tektonofizicheskie issledovaniya pri almazopoiskovykh rabotakh. Metodicheskoe posobie [Tectonophysical research at diamond prospecting works. Toolkit]. Moscow, Nauchnyi mir publ., 2008, 175 p.
(In Russ.)
9. Dukardt Yu. A., Boris E. I. Avlakogenez i kimberlitovyi magmatizm [Avlacogenesis and kimberlite magmatism]. Voronezh: Voronezh State University publ., 2000, 161 p. (In Russ.)
10. Afanas'ev V. P., Zinchuk N. N., Tychkov S. A. Problema almazonosnosti Sibirskoi platformy [The problem of diamond content of the Siberian platform]. Vestnik Voronezhskogo gosudarstvennogo universiteta. Seriya: Geologiya – Proceedings of Voronezh State University. Series: Geology, 2002, no. 1, pp. 19–36. (In Russ.)
11. Savko A. D., Zinchuk N. N., Shevyrev L. T., Il'yash V. V., Afanas'ev N. S. Almazonosnost' Voronezhskoi anteklizy [Diamond content of the Voronezh anteclise]. Trudy Nauchno-issledovatel'skogo Instituta Geologii [The work of the Research Institute of Geology], Voronezh, VSU Publ., 2003, vol.17, 121 p. (In Russ.)
12. Afanas'ev V. P., Zinchuk N. N. Osnovnye litodinamicheskie tipy oreolov indikatornykh mineralov kimberlitov i obstanovki ikh formirovaniya [Basic lithodynamic types of halos of indicator minerals of kimberlites and conditions of their formation]. Geologiya rudnykh mestorozhdenii – Geology of ore deposits, 1999, vol. 41, no. 3, pp. 281–288. (In Russ.)
13. Zinchuk N. N., Koptil' V. I., Boris E. I., Lipashova A. N. Tipomorfizm almazov iz rossypei Sibirskoi platformy kak osnova poiskov almaznykh mestorozhdenii [Typomorphism of diamonds from placers of the Siberian platform as a basis for prospecting for diamond deposits]. Rudy i metally – Ores and metals, 1999, no. 3, pp. 18–30. (In Russ.)
14. Zinchuk N. N., Savko A. D., Koptil' V. I., Chashka A. I., Polkanov Yu. A., Palkina E. Yu., Khrenov A. Ya., Shevyrev L. T. Sravnitel'naya kharakteristika tipomorfnykh osobennostei almazov iz terrigennykh otlozhenii Voronezhskoi anteklizy (Lipetskaya oblast') i Ukrainskogo shchita (Srednee Pridnestrov'e) v svyazi s problemoi prognozirovaniya i poiskov ikh korennykh istochnikov [Comparative characteristic of typomorphic features of diamonds from terrigenous deposits of the Voronezh anteclise (Lipetsk region) and the Ukrainian shield (Middle Transnistria) in connection with the problem of forecasting and searching for their primary sources]. Vestnik Voronezhskogo gosudarstvennogo universiteta. Seriya: Geologiya – Proceedings of Voronezh State University. Series: Geology, 2004, no. 2, pp. 99–110. (In Russ.)
15. Kotel'nikov D. D., Zinchuk N. N. Osobennosti glinistykh mineralov v otlozheniyakh razlichnykh osadochnykh formatsii [Features of clay minerals in deposits of various sedimentary formations]. Izvestiya VUZov. Geologiya i razvedka – Proceedings of higher educational establishments. Geology and Exploration, 1997, no. 2, pp. 53–63. (In Russ.)
16. Kotel'nikov D. D., Zinchuk N. N. Usloviya nakopleniya i postsedimentatsionnogo preobrazovaniya glinistykh mineralov v otlozheniyakh terrigennoi formatsii [Conditions of accumulation and postsedimentary transformation of clay minerals in the sediments of the terrigenous formation]. Byulleten' Moskovskogo obshchestva ispytatelei prirody. Otdel geologichesk – Bulletin of the Moscow Society of Naturalists. Geological department, 2001, vol. 76, no. 1, pp. 45–53. (In Russ.)
17. Kotel'nikov D. D., Zinchuk N. N. Ob anomalii obshchei skhemy preobrazovaniya razbukhayushchikh glinistykh mineralov pri pogruzhenii soderzhashchikh ikh otlozhenii v stratisferu [On the anomaly of the general scheme of transformation of swelling clay minerals
during the immersion of sediments containing them into the stratisphere]. Vestnik Voronezhskogo gosudarstvennogo universiteta. Seriya: Geologiya – Proceedings of Voronezh State University. Series: Geology, 2003, no. 2, pp. 57–68. (In Russ.)
18. Kotel'nikov D. D., Zinchuk N. N., Kuz'min V. A. Morfogeneticheskie raznovidnosti kaolinita v korakh vyvetrivaniya i osadochnom chekhle zemnoi kory. Stat'ya 1. Mekhanizm obrazovaniya kaolinita v korakh vyvetrivaniya razlichnykh petrokhimicheskikh tipov porod
[Morphogenetic varieties of kaolinite in weathering crusts and sedimentary cover of the earth's crust. Article 1. The mechanism of kaolinite formation in weathering crusts of various petrochemical types of rocks]. Izvestiya VUZov. Geologiya i razvedka – Proceedings of higher educational establishments. Geology and Exploration, 2006, no. 5, pp. 19–25. (In Russ.)
19. Zinchuk N. N., Spetsius Z. V., Zuenko V. V., Zuev V. M. Kimberlitovaya trubka Udachnaya (veshchestvennyi sostav i usloviya formirovaniya) [Udachnaya kimberlite pipe (material composition and formation conditions)]. Novosibirsk, NGU publ., 1993, 147 p. (In Russ.)
20. Khitrov V. G., Zinchuk N. N., Kotel'nikov D. D. Primenenie klaster-analiza dlya vyyasneniya zakonomernostei vyvetrivaniya porod razlichnogo sostava [Application of cluster analysis to clarify the weathering patterns of rocks of different composition]. Reports of the Academy of Sciences of the USSR – Doklady AN SSSR, 1987, vol. 296, no. 5, pp.1228–1233. (In Russ.)
21. Vasilenko V. B., Zinchuk N. N., Kuznetsova L. G. Geodinamicheskii kontrol' razmeshcheniya kimberlitovykh polei tsentral'noi i severnoi chastei Yakutskoi kimberlitovoi provintsii (petrokhimicheskii aspekt) [Geodynamic control of the location of kimberlite fields
in the central and northern parts of the Yakutsk kimberlite province (petrochemical aspect)]. Vestnik Voronezhskogo gosudarstvennogo universiteta. Seriya: Geologiya – Proceedings of Voronezh State University. Series: Geology, 2000, no.3(9), pp. 37–55. (In Russ.)
22. Kvasnitsa V. N., Zinchuk N. N., Koptil' V. I. Tipomorfizm mikrokristallov almaza [Typomorphism of diamond microcrystals]. Moscow, Nedra publ., 1999, 224 p. (In Russ.)
23. Afanas'ev V. P., Zinchuk N. N. Mineralogiya drevnikh rossypei almazov vostochnogo borta Tungusskoi sineklizy [Mineralogy of ancient diamond placers of the eastern side of the Tunguska syneclise]. Geologiya i geofizika – Geology and geophysics, 1987, no. 1, pp. 90–96. (In Russ.)
24. Matsyuk S. S., Zinchuk N. N. Opticheskaya spektroskopiya mineralov verkhnei mantii [Optical spectroscopy of minerals of the upper mantle]. Moscow, Nedra publ., 2001, 428 p. (In Russ.)
25. Zinchuk N. N., Boris E. I., Yanygin Yu. B. Osobennosti mineragenii almaza v drevnikh osadochnykh tolshchakh (na primere verkhnepaleozoiskikh otlozhenii Sibirskoi platformy) [Peculiarities of diamond minerageny in ancient sedimentary strata (on the example
of the Upper Paleozoic deposits of the Siberian platform)]. Moscow, MGT publ., 2004, 172 p. (In Russ.)
26. Zinchuk N. N., Mel'nik Yu. M., Serenko V. P. Apokimberlitovye porody [Apokimberlite rocks]. Geologiya i geofizika – Geology and geophysics, 1987, no. 10, pp. 66–72. (In Russ.)
27. Zinchuk N. N., Zuev V. M., Koptil' V. I., Chernyi S. D. Strategiya vedeniya i rezul'taty almazopoiskovykh rabot [Strategy of conducting and results of diamond prospecting operations]. Gornyi vestnik – Mining Bulletin, 1997, no. 3, pp. 53–57. (In Russ.)
28. Afanas'ev V. P., Zinchuk N. N., Logvinova A. N. Osobennosti raspredeleniya rossypnykh almazov, svyazannykh s dokembriiskimi istochnikami [Peculiarities of distribution of placer diamonds associated with Precambrian sources]. Zapiski Rossiiskogo mineralogicheskogo obshchestva – Notes of the Russian Mineralogical Society, 2009, vol. 138, no. 2, pp. 1–13. (In Russ.)
29. Afanas'ev V. P., Zinchuk N. N., Griffin V. L., Natapov L. M., Matuchyan G. A. Diamond prospects in the Southwestern plankt of the Tungusk Sineklise. Geology of ore Deposits, 2005, vol.47, no. 1, pp. 45–62.
30. Vasilenko V. B., Kuznetsova L. G.,Volkova N. I.,Zinchuk N. N.,Krasavchikov V. O. Diamond potential estimation based on Kimberlite major element chemistry. Journal of Geochemical Exploration, 2002, vol.76, no. 2, pp. 93–112. DOI
31. Grachanov S. A., Zinchuk N. N., Sobolev N. V. The age of Predictable primary diamond sources in the Northeastern Siberian platform. Doklady Earth Sciences, 2015, vol. 465, no. 2, pp. 1297–1301. DOI
32. Serov I. V., Garanin V. K., Zinchuk N. N., Rotman A. Ya. Mantle Sources of the kimberlite Volcanism of the Siberian Platform. Petrology, 2001, vol. 9, no.6, pp. 576–588.
33. Savko A. D., Shevyrev L. T., Il'yash V. V. Assotsiatsiya mineralov-indikatorov almazonosnosti v osadochnom chekhle Voronezhskoi anteklizy. Problemy almaznoi geologii i nekotorye puti ikh resheniya. Voronezh, 2001. C. 423–433.
33. Savko A. D., Shevyrev L. T., Il'yash V. V. Assotsiatsiya mineralov-indikatorov almazonosnosti v osadochnom chekhle Voronezhskoi anteklizy [Association of diamond indicator minerals in the sedimentary cover of the Voronezh anteclise]. Problemy almaznoi geologii i nekotorye puti ikh resheniya [Problems of diamond geology and some ways to solve them.]. Voronezh, 2001, pp. 423–433. (In Russ.)
34. Chereshinskiy A. V., Savko A. D. Aktsessornye mineraly bazal'nykh gorizontov Voronezhskoi anteklizy (v svyazi s voprosami almazonosnosti) [Accessory minerals of the basal horizons of the Voronezh anteclise (in connection with the diamond content).]. Trudy
Nauchno-issledovatel'skogo Instituta Geologii [The work of the Research Institute of Geology], Voronezh, VSU Publ., vol. 48, 2007, 120 p. (In Russ.)
35. Zinchuk N. N., Savko A. D., Shevyrev L. T. Istoricheskaya minerageniya. [Historical Minerageny]. In 3 vol. Vol. 1. Vvedenie v istoricheskuyu minerageniyu. [Introduction to historical minerageny].Voronezh, VSU publ., 2005, 587 p; Vol. 2. Istoricheskaya minerageniya drevnikh platform. [Historical Minerageny of Ancient Platforms]. Voronezh, VSU publ., 2007, 570 p. Vol. 3. Istoricheskaya minerageniya podvizhnykh superpoyasov. [Historical minerageny of mobile superbelts]. Voronezh, VSU publ., 622 p. (In Russ.).
