Geological structure of central Vietnam by interpretation processing of gravitational survey data using the “COSCAD 3D” computer technology

Background. The central regions of Vietnam are of strategic importance for the Republic, being, in fact, the gateway to the ASEAN countries. Investing in the exploration and evaluation of mineral resources, in particular ore minerals hidden at great depths, is a specific and necessary task for the country.
Aim. To clarify the structural-tectonic scheme of the analysed area and to identify the main fault systems and zoning of the Central Vietnam area by the gravitational field based on classification algorithms.
Materials and methods. The objectives were achieved by assessing the total gradient of the gravitational field, analysing the distribution of the field variance and the results of tracing the axes of the gravitational field anomaly. Interpretation processing of gravity data was carried out using the “COSCAD 3D” computer technology of statistical and spectral correlation data analysis.
Results. The defined fault systems, which play an important role in the processes of mineral formation, have a northwestern, northeastern and latitudinal strike. The zoning of the study area according to the gravitational field, its characteristics and available geological information made it possible to identify 13 homogeneous areas. Each area is characterised by a certain level of gravitational field, the values of dispersion and total field gradient, as well as correlations between attributes. The classification results confirms the complexity of the geological structure of the area under study and the presence of three main strikes of the systems of tectonic dislocations – northwestern, northeastern and latitudinal.
Conclusions. A large number of tectonic dislocations of various strikes and intensities, revealed using the methods of the probabilistic-statistical approach, implemented in the “COSCAD 3D” computer technology, indicates that the area under study is promising in terms of ore deposits.

1. Blakely R.J. Potential theory in gravity and magnetic application. Cambridge University Press, 1996. 441 p.

2. Kerimov I.A, Petrov A.V., Abubakarova E.A. The Use of Software Complex “Koskad 3D” to Analyze Potential Fields of Terek-Caspian Arch. Dagestan State Pedagogical University. Journal. Natural and Exact Sciences. 2018. Vol. 12. No. 3. P. 88—96. https://doi.org/10.31161/1995-0675-2018-12-3-88-96 (In Russian).

3. Ministry of Natural Resources and Environment, No 05/2011 / TT-BTNMT dated January 29, 2011. For: Technical regulation on ground gravity exploration method. Hanoi, 2011. 150 p. (In Vietnam).

4. Mudretsova E.A. Gravity prospecting. Geophysicist. Moscow: Nedra, 1981. 396 p. (In Russian).

5. Nguyen Truong Luu, et al. Scheme of the flight measuring gamma spectrum scale of 1:50 000 and gravity measurement scale of 1:100 000 in central Vietnam. Federation of Geophysics, General Department of Geology and Minerals of Vietnam, 2000. 250 p. (In Vietnam).

6. Nguyen Xuan Son, et al. Scheme of the flight measuring magnetic — gamma spectrum scale of 1:50 000 and gravity measurement scale of 1:100 000 in Kon Tum area. Federation of Geophysics, General Department of Geology and Minerals of Vietnam, 2000. 150 p. (In Vietnam).

7. Quyen Minh Nguyen, et al. Cambrian intra-oceanic arc trondhjemite and tonalite in the Tam Ky — Phuoc Son Suture zone, central Vietnam: Implications for the early Paleozoic assembly of the Indochina block //Gondwanna Research. 2019. No 70. P. 151—170.

8. Nikitin D.S., Gorskikh P.P., Khutorskoy M.D., Ivanov D.A. Analysis and numerical modeling of potential fields in the North-East of the Barents Sea // Earth Sciences. 2017. No 1(30). P. 6—15 (In Russian).

9. Nikitin. D.S., Ivanov D.A. Complex structural and tectonic zoning of the North-Eastern part of the Barents Sea shelf // Georesursy, 2018. T. 20. No 4. Part 2, 2018. P. 404—412 (In Russian).

10. Nikitin A.A., Petrov A.V. Theoretical foundations of geophysical information processing. Tutorial. Moscow, 2017. 127 p. (In Russian).

11. Petrov A.V., Yudin D.B., Soeli Hou. Processing and interpretation of geophysical data by methods of a probabilistic-statistical approach using computer technology “COSCAD-3D”// Bulletin Kraunts. Earth sciences. 2010. No 2. P. 126—132 (In Russian).

12. Hai Thanh Tran, et al. The Tam Ky-Phuoc Son shear zone in central Vietnam: Tectonic and metallogrnic implications // Gondwana Research. 2014. No 26. P. 144—164.

13. https://baotainguyenmoitruong.vn/danh-gia-tiemnang-khoang-san-vung-trung-trung-bo 292381.html

14. https://topex.ucsd.edu/cgi-bin/get_data.cgi

15. http://www.coscad3d.ru/index.php