Abstract
Analyses of about 6000 km of processed magnetic data in the central Bay of Bengal using Analytical Signal Processing and Werner Deconvolution techniques revealed that the depth to top of the magnetic basement varies between 5 and 12 km from the sea surface, where the water column thickness is about 3.4 km. These inferred depths are comparable to the reported acoustic basement depths. The basement map derived from magnetic interpretation defines the general configuration of the central Bay of Bengal. The N10–12° W trending subsurface 85° E Ridge buried under 2 to 3 km thick sediments is a prominent tectonic feature. Offshore basins characterised by deeper magnetic basement (∼ 9 km) and 100–200 km wide are present on either sides of the ridge. These basins were filled with 6–8 km thick lower Cretaceous to recent sediments. Integrated geophysical study depicts that the magnetic basement is characterised by NW-SE, NE-SW, NNE-SSW, N10-12° W and E-W trending structural features that are associated with the lower Cretaceous ocean floor. The Analytical Signal Processing and Werner Deconvolution techniques proved to be effective in determining the depth to the basement in areas covered by thick sediment overburden and characterized by a complex geologic/tectonic framework.
Similar content being viewed by others
References
Atchuta Rao, D., Ram Babu, H. V. and Sanker Narayan, P. V., 1981, Interpretation of magnetic anomalies due to dikes: The complex gradient method. Geophysics 46, 1572-1578.
Blakely, R. J., 1995, Potential theory in gravity and magnetic applications, Cambridge University Press, 441 pp.
Brune, J. N. and Singh, D. D. 1986, Continent-like crustal thickness beneath the Bay of Bengal sediments. Seismological Society of America Bulletin 76, 191-203.
Carter, D. J. T., 1980, Echosounding correction tables (formerly Mathew's tables), Hydrographic Department, Ministry of Defence, Taunton, 150 pp.
Curray, J. R., 1994, Sediment volume and mass beneath the Bay of Bengal. Earth Planet. Sci. Lett. 125, 371-383.
Curray, J. R., Emmel, F. J., Moore, D. G., and Russel, W. R., 1982, Structure, tectonics and geological history of the Northeastern Indian Ocean. In: A. E. Nairn and F. G. Stehli (Editors), The Ocean Basins and Margins: The Indian Ocean. Plenum, New York, 6, 399-450.
Duncan, R. A., 1991. Age distribution of volcanism along aseismic ridges in the eastern Indian Ocean. Proc. ODP, Sci. Results, College Station, Texas, Ocean Drilling Program 121, 507-517.
Duncan, R. A. and Storey, M., 1992, The life cycle of Indian Ocean hotspots. In: R. A. Duncan et al. (eds.), Synthesis of Results from scientific drilling in the Indian Ocean. Geophys. Monogr. Ser. AGU, Washington, D.C., 70, pp. 91-104.
Fisher, R. L., Jantsch, M. J. and Comer, R. L., 1982, General Bathymetric chart of the Oceans (GEBCO), Canadian Hydrographic Service, Ottawa, Canada.
Gansser, A., 1981, The Geodynamic history of the Himalaya. In: H. K. Gupta and F. M. Delany (eds.), Zagros Hindukush, Himalaya, Geodynamic Evolution, Am. Geophy. Union. Geodyn. Sem., 3, pp. 11-121.
Hartman, R. R, Teskey, D. J., Friedberg, J. L., 1971, A system for rapid digital aeromagnetic interpretation. Geophysics 36, 891-918.
Hjelt, S. E., 1973, Experiences with automatic magnetic interpretation using the thick plate model. Geophys. Prosp. 21, 243-265.
IAGA Division, V. Working group 8, 1995, International Geomagnetic Reference Field, 1995 Revision, adopted at XXI general assembly of International Union of Geodesy and Geophysics (IUGG) held in Boulder, Colorado.
Johnson, W. W., 1969, A least squares method of interpreting magnetic anomalies caused by two-dimensional structures. Geophysics 34, 65-74.
Klootwijik, J., Gee, J. W., Peirce, G. H., Smith, P. L. and Faddam, M. C., 1992, An early India Asia Contact, Paleomagnetic constraints from Ninetyeast ridge, O.D.P leg 121. Geology 20, 395-398.
Krishna, K. S., Gopala Rao, D., Ramana, M. V., Subrahmanyam, V., Sarma, K. V. L. N. S., Pilipenko, A. I., Shcherbakov, V. S. and Radhakrishna Murthy, I. V., 1995, Tectonic model for the evolution of oceanic crust in the northeastern Indian Ocean from the Late Cretaceous to the Early Tertiary. J. Geophys. Res. 100, 20,011-20,024.
Krishna, K. S., Ramana, M. V., Gopala Rao, D., Murthy, K. S. R., Malleswara Rao, M.M., Subrahmanyam, V. and Sarma, K. V. L. N. S., 1998, Periodic deformation of oceanic crust in the Central Indian Ocean. J. Geophys. Res. 103, 17,859-17,875.
Ku, C. C., 1976, Numerical inverse magneto telluric problems. Geophysics 41, 276-286.
Ku, C. C. and Sharp, J. A., 1983, Werner Deconvolution for automated magnetic interpretation and its refinement using Marquardt's inversed modeling. Geophysics 48, 754-774.
Liu, C. S., Curray, J. R. and McDonald, J. M., 1983, New constraints on the tectonic evolution of eastern Indian Ocean. Earth Planet. Sci. Lett. 65, 331-342.
Maria Desa, M. V. Ramana and T. Ramprasad, 2001, Seafloor spreading magnetic anomalies Southeast of Sri Lanka, 38th Annual Convention of Indian Geophysical Union, 18-20, December 2001, held at Visakhapatnam, Andhra Pradesh, India, abstract, p. 47.
McGrath, P. H. and Hood, P. J., 1973, An automatic least-squares multi-model method of magnetic interpretation. Geophysics 38, 348-358.
McKenzie, D. P. and Sclater, J. G., 1971, The evolution of the Indian Ocean since the Late Cretaceous. Geophys. J. R. Astron. Soc. 25, 437-528.
Mukhopadhyay M. and Krishna M. R., 1991, Gravity field and deep structure of the Bengal Fan and its surrounding continental margins, northeastern Indian. Tectonophysics 186, 365-386.
Nabighian, M. N., 1972, The analytical signal of two dimensional magnetic bodies with polygonal cross section, its properties and use for automated anomaly Interpretation. Geophysics 37, 507-517.
Nabighian, M. N., 1974, Additional comments on the analytic signal of two-dimensional magnetic bodies with polygonal crosssection. Geophysics 39, 85-92.
Norton, I. O. and Sclater, J. G., 1979, A model for the evolution of the Indian Ocean and the break up of Gondwana land. J. Geophy. Res. 84, 6803-6830.
Pateria, M. L., Rangaraju, M. K. and Raiverman, V., 1992, A note on the structure and stratigraphy of Bay of Bengal sediments. In: Recent Geoscientific Studies in the Bay of Bengal and the Andaman Sea, Spec. Publ. Ser. Geol. Surv. India 29, 21-23.
Patriat, P. and Achache, J., 1984, India Eurasia Collision chronology has implications for crustal shortening and driving mechanism for plates. Nature 311, 615-621.
Patriat, P. and Segoufin, J., 1988, Reconstruction of the central Indian Ocean. Tectonophysics 155, 211-234.
Powell, C. McA., Roots, S. R. and Veevers, J. J., 1988, Prebreakup continental extension in east Gondwanaland and the early opening of the eastern Indian Ocean. Tectonophysics 155, 261-283.
Ramana, M. V., Nair, R. R., Sarma, K. V. L. N. S., Ramprasad, T., Krishna, K. S., Subrahmanyam, V., Maria D'Cruz., Subrahmanyam, C., John Paul, Subrahmanyam, A. S. and Chandra Sekhar, D. V., 1994, Mesozoic magnetic anomalies in the Bay of Bengal. Earth Planet. Sci. Lett. 121, 469-475.
Ramana, M. V., Subrahmanyam, V., Sarma, K. V. L. N. S., Maria Desa, Malleswara Rao, M. M. and Subrahmanyam, C., 1997a, Record of the Cretaceous magnetic quiet zone A precursor to the understanding of Evolutionary history of the Bay of Bengal. Curr. Sci. 72, 669-673.
Ramana, M. V., Subrahmanyam, V., Chaubey, A. K., Ramprasad, T., Sarma, K. V. L. N. S., Krishna, K. S., Maria Desa. and Murty, G. P. S., 1997b, Structure and origin of the 85 E Ridge. J. Geophys. Res. 120, 17995-18012.
Ramana, M. V. and Ramprasad, T., 2000, Need to define deep crustal structure of the Bay of Bengal a major constituent of the north-eastern Indian Ocean. Curr. Sci. 78, 1408-1409.
Ramana, M. V., Krishna, K. S., Ramprasad, T., Maria Desa, Subrahmanyam, V and Sarma, K. V. L. N. S., 2001b, Structure and tectonic evolution of the Northeastern Indian Ocean, In: R. Sengupta and Ehrlich Desa (eds.), The Indian Ocean-a perspective, Vol. 2, 731-816.
Ramana, M. V., Ramprasad, T. and Desa, M., 2001, Seafloor spreading magnetic anomalies in the Enderby Basin, East Antarctica. Earth Planet. Sci. Lett. 191, 223-237.
Rao, T. C. S. and Rao, V., 1986, Some structural features of Bengal. Tectonophysics 124, 141-153.
Rao, D. G., Bhattacharya, G. C., Ramana, M. V., Subrahmanyam.,V. Ramprasad, T., Krishna, K. S., Chaubey, A. K., Murty, G. P. S., Srinivas, K., Desa, M., Reddy, S. I., Ashalatha, B., Subrahmanyam, C., Mittal, G. S., Drolia, R. K., Rai, S. K., Ghosh, S. K., Singh, R. N. and Majumdar, R., 1994, Analysis of multi channel seismic reflection and magnetic data along 13 N Latitude across the Bay of Bengal. Mar. Geophy. Res. 16, 225-236.
Roest, W. R., Verhoef, J. and Pilkington, M., 1992, Magnetic interpretation using the 3-D analytic signal. Geophysics 57, 116-125.
Royer, J-Y, Sclater, J. G. and Sandwell, D. T., 1989, A preliminary tectonic chart of the Indian Ocean. Proc. Ind. Acad. Sci., (Earth Planet. Sci.) 98, 7-24.
Royer, J.-Y., Sclater, J. G., Sandwell, D. T., Cande, S. C., Schlich, R., Munschy, M., Dyment, J., Fisher, R. L., Muller, R. D., Coffin, M. F., Patriat, Ph. and Bergh, H. W., 1992, Indian Ocean plate reconstructions since the Late Jurassic. In: R.A. Duncan et al., (eds.), Synthesis of Results from Scientific Drilling in the Indian Ocean. Geophys. Monogr. Ser., AGU, Washington, D.C., 70, pp. 471-475.
Sandwell, D. T. and Smith, W. H. F., 1997, Marine gravity anomaly from GEOSAT and ERS-1satellite altimetry. J. Geophys. Res. 102, 10039-10054.
Schlich, R., 1982. The Indian Ocean, aseismic ridges, spreading centers and basins. In:, A. E. Nairn and F. G. Stehli (eds.), The Ocean Basins and Margins: The Indian Ocean. Plenum, New York, 6, pp. 51-147.
Subrahmanyam, V., Ramana, M. V., Subrahmanyam, C., Krishna, K. S., Sarma, K. V. L. N. S., Desa, M., and Lakhminarayana, S., 1995, Gravity studies in the Bay of Bengal. 32nd Ann. Con. and Sem. on Mar. Geophy. Held at Hyderabad, 19-21 Dec. 1995, Extended abstracts, 8pp.
Weis, D., and Frey, F. A., 1991, Isotope geochemistry of Ninetyeast Ridge basement basalts: SR, ND, and PB evidence for involvement of the Kerguelen hotspot, Proc. ODP, Sci. Results, College Station, Texas, Ocean Drilling Program 121, 591-610.
Weis, D., Frey, F. A., Saunders, A., Gibson, I. and Leg 121 Scientific Shipboard party, 1991, Ninetyeast Ridge (Indian Ocean): A 5000 km record of a Duple mantle plume, Geology 19, 99-102.
Werner, S., 1953, Interpretation of magnetic anomalies at sheet-like bodies. Sveriges Geol. Unders., Ser. C., Arsbok, 43, 6, 130 pp.
Wessel, P. and Smith, W. H. F., 1998, New improved version of Generic Mapping Tools released. EOS Trans. AGU 79, 579.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sarma, K., Ramana, M., Ramprasad, T. et al. Magnetic basement in the central Bay of Bengal. Marine Geophysical Researches 23, 97–108 (2002). https://doi.org/10.1023/A:1022491030001
Issue Date:
DOI: https://doi.org/10.1023/A:1022491030001