Crustal deformation of the Central Indian Ocean, south of Sri Lanka as inferred from gravity and magnetic data




CIOB, deformation, tentative, basement, tectonic, 2D gravity model


Bathymetry, gravity, and magnetic data across the Central Indian Ocean Basin (CIOB) along a WE track between 5°N to 1°N latitudes and 77°E to 90°E longitudes are used to identify crustal deformation due to tectonic features such as the Comorin Ridge, 85°E ridge, Ninety East Ridge, and major fracture zones. The tectonic features were interpreted along the North Central Indian Ocean using 2D gravity modelling to understand the origin and tectonic activity of the subsurface features. The Comorin Ridge is coupled with gravity anomalies with small amplitude varying 25–30 mGal in comparison with the ridge relief which suggests that the ridge is compensated at deeper depths. The focus of the present study is to prepare a reasonable crustal model of the Central Indian Ocean using gravity and magnetic data. The crustal depths of the Central Indian Ocean Basin (CIOB) determined from gravity data using the spectral method are compared with the 2D gravity modelling results. It has been observed that the crustal depths obtained from the Spectral method are in good correlation with results obtained from 2D gravity modelling. The average basement depths for the profiles were obtained as ~5 km and perhaps deviated approximately 1–2 km from the mean. In the case of curie isotherm, the crustal depths vary 9–12 km for all magnetic profiles which may indicate deformation.


Download data is not yet available.


Amante C. & Eakins B.W., 2009. ETOPO1 1 arc- minute global relief model: procedures, data sources and analysis. NOAA Technical Memorandum NESDIS NGDC-24.

Bastia R., Radhakrishna M., Das S., Kale A.S. & Catuneanu O., 2010. Delineation of the 85 E ridge and its structure in the Mahanadi Offshore Basin, Eastern Continental Margin of India (ECMI), from seismic reflection imaging. Marine and Petroleum Geology, 27(9), 1841–1848.

Bull J.M. & Scrutton R.A., 1990. Fault reactivation in the central Indian Ocean and the rheology of oceanic lithosphere. Nature, 344(6269), 855–858.

Bull J.M., Martinod J. & Davy P., 1992. Buckling of the oceanic lithosphere from geophysical data and experiments. Tectonics, 11, 537–548.

Curray J.R. & Moore D.G., 1971. Growth of the Bengal deep-sea fan and denudation in the Himalayas. Geological Society of America Bulletin, 82(3), 563–572.[563:GOTBDF]2.0.CO;2.

Curray J.R., Emmel F.J., Moore D.G. & Raitt R.W., 1982. Structure, Tectonics, and Geological History of the Northeastern Indian Ocean. [in:] Nairn A.E.M. & Stehli F.G. (eds.), The Ocean Basins and Margins, Springer, Boston, MA, 399–450.

Christensen N.I., 1982. Seismic Velocities. [in:] Carmichael R.S. (ed.), Handbook of Physical Properties of Rocks. Volume II, CRC Press, Boca Raton, 1–228.

Curray J.R. & Munasinghe T., 1991. Origin of the Rajmahal Traps and the 85 E ridge: Preliminary reconstructions of the trace of the Crozet hotspot. Geology, 19(12), 1237–1240.<1237:OOTRTA>2.3.CO;2.

Desa M.A., Ismaiel M., Suresh Y. & Krishna K.S., 2018. Oblique strike-slip motion of the Southeastern Continental Margin of India: Implication for the separation of Sri Lanka from India. Journal of Asian Earth Sciences, 156, 111–121.

Geller C.A., Weissel J.K. & Anderson R.N., 1983. Heat transfer and intraplate deformation in the central Indian Ocean. Journal of Geophysical Research: Solid Earth, 88(B2), 1018–1032.

Gopala Rao D., Krishna K.S., Neprochnov Yu.P. & Grinko B.N., 2004. Satellite gravity anomalies and crustal features of the Central Indian Ocean Basin. Current Science, 86(7), 948–957.

Haxby W.F., 1987, Gravity Field of the World’s Oceans: A Portrayal of Gridded Geophysical Data Derived from GEOSAT Rader Altimeter Measurements of the Shape of the Ocean Surface. Department of the US Navy, Office of Naval Research and NOAA Data Center, Boulder [map].

Kahle H.G., Naini B.R., Talwani M. & Eldholm O., 1981. Marine geophysical study of the Comorin ridge, north central Indian basin. Journal of Geophysical Research: Solid Earth, 86(B5), 3807–3814.

Krishna K.S., Ramana M.V., Rao D.G., Murthy K.S.R., Rao M.M., Subrahmanyam V. & Sarma K.V.L.N.S., 1998. Periodic deformation of oceanic crust in the central Indian Ocean. Journal of Geophysical Research: Solid Earth, 103(B8), 17859–17875.

Krishna K.S., Rao D.G. & Neprochnov Y.P., 2002. Formation of diapiric structure in the deformation zone, central Indian Ocean: A model from gravity and seismic reflection data. Journal of Earth System Science, 111(1), 17–28. BF 02702219.

Krishna K.S., Michael L., Bhattacharyya R. & Majumdar T.J., 2009. Geoid and gravity anomaly data of conjugate regions of the Bay of Bengal and Enderby Basin: New constraints on breakup and early spreading history between India and Antarctica. Journal of Geophysical Research: Solid Earth, 114(B3).

Liu C.S., Sandwell D.T. & Curray J.R., 1983. The negative gravity field over the 85 E Ridge. Journal of Geophysical Research: Solid Earth, 87(B9), 7673–7686.

Maus S. & Dimri V.P., 1994. Scaling properties of potential fields due to scaling sources. Geophysical Research Letters, 21(10), 891–894.

Maus S. & Dimri V., 1995. Potential field power spectrum inversion for scaling geology. Journal of Geophysical Research: Solid Earth, 100(B7), 12605–12616.

Maus S. & Dimri V., 1996. Depth estimation from the scaling power spectrum of potential fields? Geophysical Journal International, 124(1), 113–120.

Maus S., Barckhausen U., Berkenbosch H., Bournas N., Brozena J., Childers V., Dostaler F. et al., 2009. EMAG2: A 2-arcmin resolution Earth Magnetic Anomaly Grid compiled from satellite, airborne, and marine magnetic measurements. Geochemistry, Geophysics, Geosystems, 10(8), Q08005.

Michael L. & Krishna K.S., 2011. Dating of the 85°E Ridge (northeastern Indian Ocean) using marine magnetic anomalies. Current Science, 100(9), 1314–1322.

Mukhopadhyay M. & Krishna M.B.R., 1995. Gravity anomalies and deep structure of the Ninetyeast Ridge north of the equator, eastern Indian Ocean – a hot spot trace model. Marine Geophysical Researches, 17(2), 201–216.

Pilkington M., Gregotski M.E. & Todoeschuck J.P., 1994. Using fractal crustal magnetization models in magnetic interpretation. Geophysical Prospecting, 42(6), 677–692.

Rabinowitz P.D. & LaBrecque J.L., 1977. The isostatic gravity anomaly: a key to the evolution of the ocean-continent boundary at passive continental margins. Earth and Planetary Science Letters, 35(1), 145–150.

Radhakrishna M., Subrahmanyam C. & Damodharan T., 2010. The thin oceanic crust below Bay of Bengal inferred from 3-D gravity interpretation. Tectonophysics, 493(1–2), 93–105.

Ramana M.V., Subrahmanyam V., Chaubey A.K., Ramprasad T., Sarma K.V.L.N.S., Krishna K.S. & Subrahmanyam C., 1997. Structure and origin of the 85 E Ridge. Journal of Geophysical Research: Solid Earth, 102(B8), 17995–18012.

Rao G.S. & Radhakrishna M., 2014. Crustal structure and nature of emplacement of the 85 E Ridge in the Mahanadi offshore based on constrained potential field modeling: Implications for intraplate plume emplaced volcanism. Journal of Asian Earth Sciences, 85, 80–96.

Rao G.S. & Singh A., 2020. Crustal architecture and isostatic compensation of the Comorin Ridge, central Indian Ocean: Implications for the breakup of east Gondwana. Journal of Asian Earth Sciences, 199, 104463.

Rao D.G., Krishna K.S. & Sar D., 1997. Crustal evolution and sedimentation history of the Bay of Bengal since the Cretaceous. Journal of Geophysical Research: Solid Earth, 102(B8), 17747–17768.

Ravi Kumar S. & Subrahmanyam M., 2020. A tentative crustal model of the central Indian Ocean South of Srilanka as inferred from gravity and magnetic data. Journal of Indian Geophysical Union, 24(1), 27–42.

Royer J.Y. & Chang T., 1991. Evidence for relative motions between the Indian and Australian Plates during the last 20 m.y. from plate tectonic reconstructions: Implications for the deformation of the Indo‐Australian Plate. Journal of Geophysical Research: Solid Earth, 96(B7), 11779–11802.

Sandwell D.T., Müller R.D., Smith W.H.F., Garcia E. & Francis R., 2014. New global marine gravity model from Cryo-Sat-2 and Jason-1 reveals a buried tectonic structure. Science, 346, 6205, 65–67.

Sclater J.G. & Fisher R.L., 1974. Evolution of the East: Central Indian Ocean, with Emphasis on the Tectonic Setting of the Ninetyeast Ridge. Geological Society of America Bulletin, 85(5), 683–702.<683:EOTECI>2.0.CO;2.

Spector A. & Grant F.S., 1970. Statistical models for interpreting aeromagnetic data. Geophysics, 35(2), 293–302.

Sreejith K.M., Krishna K.S. & Bansal A.R., 2008. Structure and isostatic compensation of the Comorin Ridge, north central Indian Ocean. Geophysical Journal International, 175(2), 729–741.

Sreejith K.M., Radhakrishna M., Krishna K.S. & Majumdar T.J., 2011. Development of the negative gravity anomaly of the 85 E Ridge, north-eastern Indian Ocean – A process oriented modelling approach. Journal of Earth System Science, 120(4), 605–615.

Sreejith K.M., Rajesh S., Majumdar T.J., Rao G.S., Radhakrishna M., Krishna K.S. & Rajawat A.S., 2013. High-resolution residual geoid and gravity anomaly data of the northern Indian Ocean – An input to geological understanding. Journal of Asian Earth Sciences, 62, 616–626.

Sreejith K.M., Unnikrishnan P. & Radhakrishna M., 2019. Isostasy and crustal structure of the Chagos–Laccadive Ridge, Western Indian Ocean: Geodynamic implications. Journal of Earth System Science, 128(6), 1–13.

Stein S. & Okal E.A., 1978. Seismicity and tectonics of the Ninetyeast Ridge area: Evidence for internal deformation of the Indian plate. Journal of Geophysical Research: Solid Earth, 83(B5), 2233–2245.

Stein C.A., Cloetingh S. & Wortel R., 1989. Seasatderived gravity constraints on stress and deformation in the northeastern Indian Ocean. Geophysical Research Letters, 16(8), 823–826.

Straume E.O., Gaina C., Medvedev S., Hochmuth K., Gohl K., Whittaker J.M., Abdul Fattah R. et al., 2019. GlobSed: Updated total sediment thickness in the world’s oceans. Geochemistry, Geophysics, Geosystems, 20(4), 1756–1772.

Subrahmanyam M. & Gebissa F.T., 2017. Performance evaluation of spectral analysis and Werner deconvolution interpretation techniques in magnetic method. Journal of Applied Geophysics, 138, 102–113.

Subrahmanyam C. & Singh R.N., 1992. Geotectonics of the Bay of Bengal. Indian Journal of Petroleum Geology, 1, 161–180.

Werner S., 1953. Interpretation of Magnetic Anomalies at Sheet-like Bodies. Sveriges geologiska undersökning. Ser. C. Avhandlingar och uppsatser, 508, Norstedt, Stockholm.

Wessel P., Matthews K., Müller R., Mazzoni A., Whittaker J., Myhill R. & Chandler M., 2015. Semi-automatic fracture zone tracking. Geochemistry, Geophysics, Geosystems, 16(7), 2462–2472.




How to Cite

Ravi Kumar, S. (2022). Crustal deformation of the Central Indian Ocean, south of Sri Lanka as inferred from gravity and magnetic data. Geology, Geophysics and Environment, 48(2), 89–110.