Abstract
Analysis of the multi-channel seismic reflection, magnetic and bathymetric data collected along a transect, 1110 km long parallel to 13° N latitude across the Bay of Bengal was made. The transect is from the continental shelf off Madras to the continental slope off Andaman Island in water depths of 525 m to 3350 m and across the Western Basin (bounded by foot of the continental slope of Madras and 85° E Ridge), the 85° E Ridge, the Central Basin (between the 85° E Ridge and the Ninetyeast Ridge), the Ninetyeast Ridge and the Sunda Arc. The study revealed eight seismic sequences, H1 to H8 of parallel continuous to discontinuous reflectors. Considering especially depth to the horizons, nature of reflection and on comparison with the published seismic reflection results of Currayet al. (1982), the early Eocene (P) and Miocene (M) unconformities and the base of the Quaternary sediments (Q) are identified on the seismic section. Marked changes in velocities also occur at their boundaries.
In the Western Basin the acoustic basement deepening landward is inferred as a crystalline basement overlain by about 6.7 km of sediment. In the Central Basin possibly thicker sediments than in the Western Basin are estimated. The sediments in the Sunda Arc area are relatively thick and appears to have no distinct horizons. But the entire sedimentary section appears to be consisting of folded and possibly faulted layers.
The comparatively broader wavelength magnetic anomalies of the Central Basin also indicate deeper depth of their origin. Very prominent double humped feature of the 85° E Ridge and broad basement swell of the Ninetyeast Ridge are buried under about 2.8 km thick sediments except over the prominent basement high near 92° E longitude. The positive structural relief of the buried 85° E Ridge in the area is reflected in magnetic signature of about 450 nT amplitude. Flexural bulge of the 85° E Ridge and subsidence of the Ninetyeast Ridge about 24 cm my−1 rate since early Eocene period have been inferred from the seismic sequence analysis.
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References
Brune, J. N. and Priestly, K., 1989, Anomalous Crustal Structure Beneath Bay of Bengal and Passive Oceanic Sedimentary Basins,Proc. Ind. Acad. Sci. (Earth Planet. Sci.) 98 25–30.
Brune, J. N. and Singh, D. D., 1986, Continental-Like Crustal Thickness Beneath the Bay of Bengal Sediments.Bull. Seismol. Soc. Am. 76 191–203.
Cochran, J., Stow, D. A. V.et al., 1987, Collisions in the Indian Ocean,Nature 330 519–521.
Cochran, J. R Stow, D. A. V.et al., 1987, Proceedings ODP, Initial Reports, 116: College Station, TX (Ocean Drilling Program) pp. 197–210.
Curray, J. R., 1991, Possible Greenschist Metamorphism at the Base of a 22-km Sedimentary Section, Bay of Bengal,Geology 19 1097–1100.
Curray, J. R., Emmel, F. J., More, D. G., and Raitt, R. W., 1982, Structure Tectonics and Geological History of the North Eastern Indian Ocean. In Nairn, A. E. M. and Stehli, F. G. (eds.),The Ocean Basins and Margins, 6, Plenum Press, New York, pp. 399–450.
Curray, J. R. and Moore, D. G., 1971, Growth of the Bengal Deep Sea Fan and Denudation of the Himalayas,Geol. Soc. America Bull. 82 563–572.
Curray, J. R. and Munasinghe, T., 1989, Timing of Intraplate Deformation, Northeastern Indian Ocean,Earth and Planetary Science Letters 94 71–77.
Curray, J. R. and Munasinghe, T., 1991, Origin of the Rajmahal Traps and the 85° E Ridge: Preliminary Reconstructions of the Trace of the Crozet Hotspot,Geology 19 1237–1240.
Holeman, G. H., 1968, The Sediment Yield of the Major Rivers of the World,Water Resources Research 4 187–197.
Le Pichon, X. and Heirtzler, J. R., 1968, Magnetic Anomalies in the Indian Ocean and Seafloor Spreading,J. Geophys. Res. 73 2101–2117.
Von der Borch, C. C., Sclater, J. G.et al., 1974, Site 218. In Von der Borch, C.C., Sclater, J.G.et al. (eds.),Initial Reports of the Deep Sea Drilling Project, 22, Washington (U.S. Government Printing Office), pp. 325–348.
Mckenzie, D. P. and Sclater, J. G., 1971, The Evolution of the Indian Ocean Since Late Cretaceous,Geophy. J. R. Astr. Soc. 25 437–528.
Morgan, W. J., 1972, Deep Mantle Convection Plumes and Plate Motions,Am. Assoc. Pet. Geol. Bull. 56 203–213.
Norton, I. O. and Sclater, J. G., 1979, A Model for the Evolution of the Indian Ocean and the Breakup of Gondwanaland,J. Geophy. Res. 84 8803–8830.
Pimm, A. C., 1972, Sedimentology and History of Northeastern Indian Ocean from Late Cretaceous to Recent. In Von der Borch, C. C., and Sclater, J. G.et al., (eds.),Initial Reports of the Deep Sea Drilling Project, 22, Washington (U.S. Government Printing Office), pp. 717–773.
Rao, T. C. S. and Bhaskara Rao, V., 1985, Geophysical Studies over the Continental Margins of the East Coast of India,Mar. Geol. 67 151–161.
Rao, T. C. S. and Bhaskara Rao, V., 1986, Some Structural Features of Bay of Bengal,Tectonophysics 124 141–153.
Sclater, J. G. and Fisher, R. L., 1974, Evolution of the East Central Indian Ocean. Emphasis on the Tectonic Setting of the Ninetyeast Ridge,Bull. Geol. Soc. Amer. 85 683–702.
Singh, D. D., 1988, Crust and Upper Mantle Velocity Structure Beneath the Northern and Central Indian Ocean from the Phase and Group Velocity of Raleigh and Love Waves,Phy. Earth Planet. Inter. 50 230–239.
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Rao, D.G., Bhattacharya, G.C., Ramana, M.V. et al. Analysis of multi-channel seismic reflection and magnetic data along 13° N latitude across the Bay of Bengal. Mar Geophys Res 16, 225–236 (1994). https://doi.org/10.1007/BF01237515
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DOI: https://doi.org/10.1007/BF01237515