Identifying the tectonically induced mineralisation zone in the central part of Dharwar-Shimoga greenstone belt, Western Dharwar Craton: an integrated analysis of gravity and magnetic data

• Autorzy: Das Niharika , Bhattacharya Sumit Kumar , Narayan Satya , Livingston D.

Identyfikatory

DOI

10.1007/s11600-023-01181-7

• Języki publikacji: EN

Abstrakty

EN

The late Archean Western Dharwar Craton supergroup has volcanic and sedimentary rocks deposited during 2900-2600 Ma underlain by the Sargur Group basement of 3.36-3.2 Ga granitic gneiss and older supracrustal rocks. The western part of the craton, known as the western province (Dharwar Foreland), comprises four major schist belts (Western Ghats-Bababudhan-Shimoga-Chitradurga). A regional gravity and magnetic (Total Field) survey was done in the Shimoga region. The geophysical data of the study area reveal the subsurface extension and behaviour of the exposed rocks of the area. The Euler deconvolution was used to define the depth of the anomaly sources. Euler depth solution for the spherical body (structural index 2), window size = 10, and depth tolerance = 5% depicts the depth of the various sources. The Euler depth solutions cluster over the hook-shaped schist rock of the Medur group (at the northern part of the area) reveals that the body's depth varies from 1 to 4 km in the central part, and at the northern flank, it goes up to 7 km. The solution also brought out the depth of the anomalous body near Hithala, within 4 km. The 2D forward depth modelling of the anomalous zone brings out the involvement of the tectonic forces in the generation of this anomalous body. The more precise depth from the model has been estimated between 2 and 3 km. The model clearly shows the relationship between schist rocks and the basement. However, the high-gravity anomaly has been modelled as the manganese bearing horizon, which has come to optimum depth because of folding and faulting in the region, thus providing a favourable zone for manganese deposition.

Słowa kluczowe

EN

gravity data; magnetic data; Euler deconvolution; 2D forward model; radially averaged power spectrum

PL

dane grawitacyjne; dane magnetyczne; dekonwolucja Eulera

• Wydawca: Instytut Geofizyki PAN ; Springer
• Czasopismo: Acta Geophysica
• Rocznik: 2024
• Tom: Vol. 72, no. 3
• Strony: 1731--1748
• Opis fizyczny: Bibliogr. 30 poz.

Twórcy

autor

Das Niharika

• Geological Survey of India, Southern Region, Bandlaguda, Nagole 500068, India

autor

Bhattacharya Sumit Kumar

• Geological Survey of India, Southern Region, Bandlaguda, Nagole 500068, India

autor

Narayan Satya

• Oil and Natural Gas Corporation Limited, Dehradun 248003, India

autor

Livingston D.

• Geological Survey of India, Southern Region, Bandlaguda, Nagole 500068, India

Bibliografia

• 1. Chadwick B, Vasudev VN, Jayaram S (1988) Stratigraphy and structure of late Archaean Dharwar volcanic and sedimentary rocks and their basement in a part of the Shimoga basin, east of Bhadravathi. Karnataka J of Geol Soc India 32:1-19
• 2. Chadwick B, Vasudev VN, Ahmed N (1996) The Sandur schist belt and its adjacent plutonic rocks implications for late Archaean crustal evolution in Karnataka. J of Geol Soc India 47(1):37-57
• 3. Chinnaiah (2014) Occurrence and distribution of manganese ore types in the Shimoga area. Ind J App Sci. 5 (1) 161-169
• 4. Geological Survey of India (2006) Geology and Mineral resources of states of India Part -VII Karnataka & Goa. Miscellaneous Publication No. 30.
• 5. Geological Survey of India (2016) Scale 1:250,000 Geological Quadrangle Map (Second Edition) of Ranibennur Quadrangle
• 6. Geological Survey of India (2018) 1:50,000 Geological Map Series Toposheet 47N/08
• 7. Ghosh GK (2015) Interpretation of gravity data and using 3D Euler deconvolution tilt angle and horizontal tilt angle source edge approximation of the North-West Himalaya. Acta Geophys. https://doi.org/10.1515/acgeo-2016-0042
• 8. Gokarn SG, Gupta G, Rao C (2004) Geoelectric Structure of The Dharwar Craton from magnetotelluric studies; Archean suture identified along the Chitragurga-Gadag schist belt. Geophy J Int 158(2):712-728
• 9. Gokarn SG, Rao CK, Gupta G (1998) MT studies over the Dharwar craton, 35th Annual convention and meeting on evolution of continental margins. Process and Potential pp 51-52.
• 10. Harinadha Babu P, Ponnuswamy M, Krishnamurthy KV (1981) Shi-moga belt in early Precambrian supracrustals of southern Karnataka. J Geol Soc India Memoir 112:199-218
• 11. Jacobsen BH (1987) A case for upward continuation as a standard separation filter for potential field maps. Geophysics 52:1138-1148
• 12. Kaila KL, Bhatia SC (1981) Gravity study along the Kavali-Udipi deep seismic sounding profile in the Indian Peninsular Shield: some inferences about the origin of Auothosites and the Eastern Ghats orogeny, Tectonophysics. J Geol Soc India 79:129-143
• 13. Miller HG, Singh V (1994) Potential feld tilt a new concept for location of potential feld sources. J App Geophys 32:213-217
• 14. Nabighian MN (1972) The analytic signal of two-dimensional magnetic bodies with polygonal cross-section: Its properties and use for automated anomaly interpretation. Geophysics 37:507-717
• 15. Narayan S, Kumar U, Pal SK, Sahoo SD (2021) New insights into the structural and tectonic settings of the Bay of Bengal using highresolution earth gravity model data. Acta Geophys 69:2011-2033
• 16. Pal SK, Narayan S, Majumdar TJ, Kumar U (2016) Structural mapping over the 85°E Ridge surroundings using EIGEN6C4 high-resolution global combined gravity field model: an integrated approach. Mar Geophys Res. https://doi.org/10.1007/s11001-016-9274-3
• 17. Qureshy MN, Aravamadhu PS, Bhatia SC (1967) Some regional gravity traverses through India. Proc Symp UMP Hyderabad pp 120-133
• 18. Radhakrishna BP, Naqv SM (1986) Precambrian continental crust of India and its evolution. J of Geol 94:145-166
• 19. Radhakrishna BP, Vaidyanadhan R (1994) Geology of Karnataka; Geol. Soc. India Bangalore, pp 298
• 20. Ramadas G, Bhagya K (2016) Tectonic classification of Dharwar Craton, India based on the inversion of regional Bouguer gravity. Int J of Adv Res. Doi:https://doi.org/10.21474/IJAR01/1480
• 21. Rao VV, Danodara N, Sain K, Sen MK, Murty ASN, Sarkar D (2015) Upper crust of the Archean Dharwar Craton in southern India as revealed by seismic refraction tomography and its geotectonic implications. Geophys J Int 200:652-663
• 22. Reid AB, Allsop JM, Granser H, Millett AT, Somerton IW (1990) Magnetic interpretation in three dimensions using Euler deconvolution. Geophysics 55(1):80-90
• 23. Roest WR, Jacob Verhoef S, Pilkington M (1992) Magnetic interpretation using the 3-D analytic signal. Geophysics 57(1):116-125
• 24. Singh AP, Mishra DC, Gupta SB, Rao MRKP (2004) Crustal structure and domain tectonics of the Dharwar Craton (India): insight from new gravity data. J of Asian Earth Sci Vol.23
• 25. Spector A, Grant FS (1970) Statistical models for interpreting aeromagnetic data. Geophysics 35:293
• 26. Srinivasan R, Naha K (1993) Archaean sedimentation in the Dharwar craton, southern India. Proc Natl Acad Sci India 63A:1-13
• 27. Subrahmanyam C, Verma RK (1981) Densities and magnetic susceptibilities of Precambrian rocks of different metamorphic grade (Southern Indian shield). J Geophys 49:101-107
• 28. Subrahmanyam C, Verma RK (1982) Gravity interpretation of the Dharwar greenstone- gneiss-granite terrain in the southern Indian shield and its geological implications. Tectonophysics 84:225-245
• 29. Swami Nath J, Ramakrishnan M (1981) Early Precambrian Supracrus-tals of Southern India. Memoirs of the Geol Surv of India 112:350
• 30. Thompson DT (1982) EULDEPTH- A new technique for making computer-assisted depth estimation from magnetic data. Geophysics 47:31-37