Abstract
The 85°E Ridge is a buried aseismic ridge running parallel to the 85°E meridian in the Bay of Bengal, India. Its origin has been a subject of debate, with opinions ranging from an abandoned spreading centre to a hotspot track. The present study follows the hotspot hypothesis and incorporates gravity, magnetic and seismic data to identify the nature and interpret the origin of the 85°E Ridge. It differs from earlier studies in the integration of deep seismic lines and gravity inversion to identify crustal architecture below the 85°E Ridge. Seismic interpretation along with gravity inversion has been used to determine the crustal structure below the ridge, while sediment thickness maps have been used to infer the uplift during the ridge emplacement. Seismic interpretations together with isostatic residual gravity anomaly map have been used to associate large negative anomalies with hotspot related magmatism. The negative anomaly increases with increasing volcanic load, indicating the presence of a crustal root and magmatic underplating. Typical flexural moat and arch, indicative of hotspot volcanism, is also observed in the seismic profiles. Gravity inversion modeling indicates an “onion-shell” like structure within the volcanic load, inferring the presence of less dense outer layers with a heavier core within the complex. Sediment thickness maps show the presence of dynamic uplift of more than 2000 milliseconds from early Cretaceous onwards. The study concludes that the 85°E Ridge is a result of hotspot volcanism, and proposes a plausible model for the origin of the structure.
Similar content being viewed by others
References
Acharyya, S.K. (1998) Break up of greater Indo-Australian continent and accretion of blocks forming south and East Asia. Jour. Geodynamics, v.26(1), pp. 149–170.
Agarwal Rama, J.K. (1976) Chronology of Mesozoic volcanics of India. Proc. Indian Acad. Sci., v.84A, pp. 157–179.
Andersen, O.B. and Knudsen, P. (1997) Global marine gravity field from the ERS-1 and Geosat geodetic mission altimetry. Jour. Geophys. Res., v.103(C4), pp. 81–9.
Baksi, A.K. (1995) Petrogenesis and timing of volcanism in the Rajmahal flood basalt province, northeastern India. Chemical Geol., v.121, pp. 73–90.
Baksi, A.K., Barmann, T.R., Paul, D.K. and Farrar, E. (1987) Widespread early Cretaceous flood basalt volcanism in eastern India: geochemical data from Rajmahal-Bengal-Sylhet Traps. Chem. Geol., v.63, pp. 133–141.
Bansal, A.R. and Dimri, V.P. (2005) Interpretation of gravity data over the 85° E ridge and Afanasy-Nikitin-seamount using spectral method. Indian Jour. Marine Sci., v.34(3), pp.279–284.
Bastia, R., Radhakrishna, M., Das, S., Kale, A.S. and 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, v.27(9), pp.1841–1848.
Bhattacharya, S. (1996) Eastern Ghats granulites terrain of India: an overview. Jour. Southeast Asian Earth Sci., v.14(3–4), pp.165–174.
Bird, D. (2009) Offshore East India, two dimensional gravity and magnetic models. Bird Geophysical, unpublished report, Reliance Industries Ltd.
Cande, S.C. and Rabinowicz, P.D. (1979) Magnetic anomalies of the continental margin of Brazil. Map, AAPG map library, Tulsa, OK, 1 sheet.
Cande, S.C., Labrecque, J.L. and Haxby, W.F. (1988) Plate kinematics of the South Atlantic; Chron C34 to present. Jour. Geophys. Res., v.93(B11), pp. 13,479–13,492.
Chang, H.K., Kowsmann, R.O., Figueiredo, A.M.F. and Bender, A.A. (1992) Tectonics and stratigraphy of the East Brazil Rift System; an overview. In: P.A., Ziegler, (Ed.), Geodynamics of rifting; Volume II, Case history studies on rifts; North and South America and Africa. Tectonophysics, pp.97–138.
Chaubey, A.K., Ramana, M.V, Sarma, K.V.L.N.S., Krishna, K.S., Murty, G.P.S., Subrahmanyam, V., Mittal, G.S. and Drolia, R.K. (1991) Marine geophysical studies over the 85°E Ridge. In: First Int. Sem. Exhbn. on Exploration Geophysics in Nineteen Nineties. AEG Publn.,v.2, pp.508–515.
Choudhuri, M., Guha, D., Dutta, A., Sinha, S. and Sinha, N. (2010) Spatio-temporal variations and kinematics of shale mobility in the Krishna-Godavari basin, India. In: L., Wood, (Ed.), Shale tectonics, AAPG Memoir, v.93, pp.91–109.
Clark Jr., S.P. (1966) Handbook of Physical Constants. Geological Society of America Memoir v.97, Geol. Soc.Amer., New York.
Cobbold, P.R., Meisling, K.E. and Mount, V.S. (2001) Reactivation of an obliquely rifted margin, Campos and Santos basins, southeastern Brazil. Amer. Assoc. Petroleum Geol., Bull., v.11, pp. 1925–1944.
Cochran, J.R. (1973) Gravity and Magnetic Investigations in the Guiana Basin, Western Equatorial Atlantic. Geol. Soc. Amer. Bull., v.84(10), pp.3249–3268.
Condie, C. (2005) Earth as an evolving planetary system. Elsevier Academic Press, Amsterdam, pp.17–25, pp.265–313
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, v.19(12), pp.1237–1240.
Curray, J.R., Emmel, F.J., Moore, D.G. and Raitt, R.W. (1982) Structure, tectonics, and geological history of the northeastern Indian Ocean. In: A.E, Nairn and F.G., Stehli,(Eds.), The Ocean Basins and Margins, The Indian Ocean., Plenum, New York, v.6, pp.399–450.
Directorate General of Hydrocarbons, India, Sedimentary basins: Bengal. http://www.dghindia.org/5.aspx, accessed April 25, 2011.
Drury, S.A., Harris, N.B.W., Holt, R.W., Reeves-Smith, G.J. and Wightman, R.T. (1984) Precambrian tectonics and crustal evolution in South India. Jour. Geol., v.92(1), pp.3-20.
Fainstein, R., Milliman, J.D. and Jost, H. (1975) Magnetic character of the Brazilian continental shelf and upper slope. Revista Brasileira de Geociencias, v.5(3), pp.198–211.
Fugro Robertson Inc. (2008) Interpretation report, offshore sedimentary basins of India. Unpublished report, Reliance Industries Ltd.
Fuloria, R.C. (1993) Geology and hydrocarbon prospects of Mahanadi basin, India. Proc. 2nd Sem. Petroliferous Basins of India, v.1, pp.355–359.
Fuloria, R.C., Pandey, R.N., Bharali, B.R. and Mishra, J.K. (1992) Stratigraphy, Structure and Tectonics of Mahanadi Offshore Basin. In: Geol. Surv. India, Spec. Publ., no.29, pp.255–265.
Gaina, C., Müller, R.D., Brown, B., Ishihara, T. and Ivanov, S. (2007) Breakup and early seafloor spreading between India and Antarctica. Geophys. Jour. Internat., v.170(1), pp.151–169.
Geological Survey Of India (1993) Geological Map of India, Scale 1:5000000
Gopala Rao, D., Bhartacharya, 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., Ashalata, 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. Geophys. Res., v.16, pp. 225–236.
Gopala Rao, D., Krishna, K.S. and Sar, D. (1997). Crustal evolution and sedimentation history of the Bay of Bengal since the Cretaceous. Jour. Geophys. Res., v.102, pp.17747–17768.
Gopalakrishnan, K. (1998) Extensions of Eastern Ghats mobile belt, India; a geological enigma. Proceedings of workshop on the Eastern Ghats mobile belt. Geol. Surv. India Spec. Publ., no.44, pp.22–38.
Gx Technology (2007) IndiaSpan East, Phase 1, Interpretation Report: Crustal Structure and Seismic Stratigraphic Interpretation. Unpublished report, Reliance Industries Ltd., 39p.
Jarchow, C.M. and Thompson, G.A. (1989) The nature of the Mohorovicic discontinuity. Annual Rev. Earth Planet. Sci. Lett., v.18, pp.357–386
Karner, G.D. (2000) Rifts of the Campos and Santos basins, southeastern Brazil; distribution and timing. In: M.R., Mello and B.J., Katz, (Eds.), Petroleum systems of South Atlantic margins. AAPG Memoir, v.73, pp.301–315.
Karner, G.D. and Driscoll, N.W. (1999). Tectonic and stratigraphic development of the WestAfrican and eastern Brazilian margins; insights from quantitative basin modelling. In: N.R., Cameron, R.H., Bate and V.S., Clure, (Eds.), The oil and gas habitats of the South Atlantic, Geol. Soc. Spec. Publ., v.153, pp.11–40.
Kent, R.W., Storey, M., Sunders, A.D., Ghose, N.C. and Kempton, P.D. (1992) Comments and reply on “Origin of the Rajmahal Traps and the 85°E Ridge: Preliminary reconstructions of the trace of the Crozet hotspot. Geology, v.20, pp.957–958.
Krishna, K.S. (2003) Structure and evolution of the Afanasy- Nikitin seamount, buried hills and 85°E ridge in the northeastern Indian Ocean. Earth Planet. Sci. Lett., v.209, pp.379–394.
Krishnan, M.S. (1982) Geology of India and Burma, 6th ed. CBS Publishers and Distributers, Delhi, 536p.
Kumar, P., Yuan, X., Ravikumar, M., Kind, R., Li, X. and Chadha, R.K. (2007) The rapid drift of Indian tectonic plate. Nature, v.449, pp. 894–897.
Liu, C.S., Sandwell, D.T. and Curray, J.R. (1982) The negative gravity field over the 85°E Ridge. Jour. Geophys. Res., v.87(B9), pp.7673–7686.
Mishra, D.C. (1991) Magnetic crust in the Bay of Bengal. Mar. Geol., v.99, pp.257–261.
Mûller, R.D., Royer, J.Y. and Lawver, L.A. (1993) Revised plate motions relative to the hotspots from combined Atlantic and Indian Ocean hotspot tracks. Geology, v.21, pp.275–278.
Murthy, K.S.R., Rao, T.C.S., Subrahmanyam, A.S., Malleswara Rao, M.M. and Lakshminarayana, S. (1993) Structural lineaments from the magnetic anomaly maps of the eastern continental margin of India (ECMI) and NW Bengal Fan. Mar. Geol., v.114, pp.171–183.
Naqvi, S.M. and Rogers, J.J.W. (1987) Precambrian Geology of India. Oxford Monographs on Geology and Geophysics, Oxford University Press, Oxford, UK.
Nemèok, M., Sinha, S.T., Stuart, C.J., Welker, C., Choudhuri, M., Sharma, S.P., Misra, A.A., Sinha, N. and Venkatraman, S. (2012) East Indian margin evolution and crustal architecture: integration of deep reflection seismic interpretation and gravity modeling. In: W.U., Mohriak, A., Danforth, P.J., Post, D.E., Brown, G.T., Tari, M., Nemèok and S.T., Sinha, (Eds.), Conjugate Divergent Margins. Geol. Soc. London, Spec. Publ.
Nemèok, M., Stuart, C., Segall, M.P., Allen, R.B., Christensen, C., Hermeston, S.A. and Davison, I. (2005) Structural development of South Morocco: interaction of tectonics and deposition. In: P.J., Post, N., Rosen, D.L., Olson, S.L., Palmes, K.T., Lyons and G.B., Newton,(Eds.), Petroleum systems of divergent continental margin basins. 25th Annual GCSSEPM Foundation Bob F. Perkins Research Conference, Session I, Crustal architecture of divergent margins, GCSSEPM, Houston, pp.151–202.
Nemèok, M., Stuart, C., Welker, C., Smith, S., Yalamanchili, R., Srivastava, D.C., Sinha, S. and Choudhuri, M. (2007) Crustal types, structural architecture, and plate configurations study of the Reliance East Coast region. Unpublished EGI Report No. 01-00059-5000-50501546, Reliance Industries Ltd.
Paul, D.K., Ray Barman, T.K., Mcnaughton, N.J, Fletcher, I.R., Pottes, P.J., Ramakrishnan, M. and Augustine, P.E. (1990) Archaean-Proterozoic evolution of Indian charnockites. Isotopic and geochemical evidence from granulites of Eastern Ghat belt. Jour. Geol., v.98, pp.253–263.
Powell, C.M., Roots, S.R. and Veevers, J.J. (1988) Pre-breakup continental extension in East Gondwanaland and the early opening of the eastern Indian Ocean. Tectonophysics, v.155, pp.261–283.
Radhakrishna, B.P. and Naqvi, S.M. (1986) Precambrian continental crust of India and its evolution. Jour. Geol., v.94(2), pp.145–146.
Radhakrishna, M., Twinkle, D., Nayak, S., Bastia, R. and Srinivasa Rao, G. (2012) Crustal structure and rift architecture across the Krishna-Godavari basin in the central Eastern Continental Margin of India based on analysis of gravity and seismic data. Marine Petroleum Geol., v.37(1), pp.129–146.
Ramakrishnan, M. (2003) Craton-mobile belt relations in Southern Granulite Terrain; Tectonics of Southern Granulite Terrain; Kuppam-Palani geo-transect. Geol. So. India Mem., no.50, pp. 1–24.
Ramakrishnan, M., Nanda, J.K. and Augustine, P.F. (1998) Geological evolution of the Proterozoic Eastern Ghats Mobile Belt. Geol. Surv. India Spec. Publ., v.44, pp.1–21.
Ramana, M.V, Nair, R.R., Sarma, K.V.L.N.S., Ramprasad, T., Krishna, K.S., Subrahmanyam, V., D’Cruz, M., Subramanyan, C., Paul, J., Subramanyam, A.S. and Chandra Sekhar, D.V. (1994) Mesozoic anomalies in the Bay of Bengal. Earth Planet. Sci. Lett., v.121, pp.469–475.
Ramana, M.V, Subrahmanyam, V., Chaubey, A.K., Ramprasad, T., Sarma, K.V.L.N.S., Krishna, K.S., Desa, M., Murty, G.P.S. and Subrahmanyam, C (1997) Structure and origin of the 85°E Ridge. Jour. Geophys. Res., v.102(B8), pp.17995–18012.
Ramana, M.V., Ramprasad, T., Desa, M. and Subrahmanyam, V. (2000) Integrated Geophysical Studies over the 85°E Ridge-Evaluation and Interpretation. Visakha Sci. Jour., v.4(1), pp.45–56.
Ray, D.K. (1963) Tectonic map of India. Geological Society of India, Calcutta, scale 1:2 000 000.
Reeves, C. and Wit, M.D. (2000) Making ends meet in Gondwana: retracing the transforms of the Indian Ocean and reconnecting continental shear zones. Terra Nova, v.12(6), pp. 272–280
Sandwell, D.T. and Smith, W.H.F. (1997) Marine Gravity Anomaly from ERS-1, Geosat & Satellite Altimetry. Journal of Geophysical Research (Solid Earth), v.102, pp. 110,039–10,045. Web source: Satellite Geodesy, Scripps institute of Oceanography, California, USA, http://topex.ucsd.edu/cgibin/get_data.cgi, accessed April 12, 2011.
Sar, D., Maheshwari, M.K., Rangarajan, S. and Bahuguna, C.S. (2009) Eighty five degree east ridge and its hydrocarbon potential. Geohorizons, v.15, http://www.spgindia.org/geohorizon/july2009/d_sar.pdf.
Sarkar, A. et al. (1980) Lamprophyres from Indian Gondwanas — K-Ar ages and chemistry. Jour. Geol. Soc. India, v.21, pp.188–193.
Schubert, G., Turcotte, D.L. and Olson, P. (2001) Mantle convection in the Earth and Planets. Cambridge University Press, Cambridge, 940p.
Sclater, J.G., Von Der Borch, C., Veevers, J.J., Hekinian, R., Thompson, R.W., Pimm, A.C., Mcgowran, B., Gartner, S., Jr. and Johnson, D.A. (1974) Regional synthesis of the deep sea drilling results from Leg 22 in the eastern Indian Ocean. In: C., Von der Borch, J.G., Sclater, S., Gartner, Jr., R., Hekinian, D.A., Johnson, B., McGowran, R.W., Thompson, J.J., Veevers, L.S., Waterman and A.C., Pimm, (Eds.), Initial reports of the Deep Sea Drilling Project, v.22, pp.815–831, Washington, D.C., U.S. Govt. Printing Office.
Sibuet, J.C., Srivastava, S. and Manatschal, G (2007) Exhumed mantle forming transitional crust in the Newfoundland-Iberia rift and associated magnetic anomalies. Jour. Geophys. Res., v.112, 23p.
Sinha, S.T., Nemcok, M., Choudhuri, M., Misra, A.A., Sharma, S.P., Sinha, N. and Venkatraman, S. (2010) The crustal architecture and continental break up of East India Passive margin: an integrated study of deep reflection seismic interpretation and gravity modeling. AAPG Annual Convention & Exhibition, New Orleans, USA, CD-ROM.
Sreejith, K.M., Radhakrishna, M., Krishna, K.S. and Majumdar, T.J. (2011) Development of the negative gravity anomaly of the 85°E Ridge, northeastern Indian Ocean — A process oriented modelling approach. Jour. Earth Syst. Sci., v.120, pp.605–615.
Storey, B.C. (1995) The role of mantle plumes in continental break up, case histories from Gondwanaland. Nature, v.377, pp.301–308.
Subrahmanyam, C., Thakur, N.K., Rao, T.G., Khanna, R., Ramana, M.V. and Subrahmanyam, V. (1999) Tectonics of the Bay of Bengal: new insights from satellite-gravity and ship-borne geophysical data. Earth and Planetary Science Letters, v.171, pp.237–251.
Subramanyam, C. and Chand, S. (2006) Evolution of passive continental margins of India — a geophysical appraisal. Gondwana Res., v.10, pp.167–178.
Tewari, H.C. (1998) The effect of thin high velocity layers on seismic refraction data: an example from Mahanadi Basin, India. Pure Appld. Geophysics, v.151, pp.63–79.
Toulokian, Y.S., Judd, W.R. and Roy, R.F. (1981) Physical properties of rocks and minerals. McGraw-Hill, New York, 548 p.
Veevers, J.J (2009) Palinspastic (pre-rift and -drift) fit of India and conjugate Antarctica and geological connections across the suture. Gondwana Res., v.16, pp.90–108.
Watts, A.B., Peirce, C., Collier, J., Dalwood, R., Canales, J.P. and Henstock, T.J. (1997) A seismic study of lithospheric flexure in the vicinity of Tenerife, Canary Islands. Earth Planet. Sci. Lett., v.146, pp.431–447.
Wilson, P.G., Turner, J.P. and Westbrook, G.K. (2003) Structural architecture of the ocean-continent boundary at an oblique transform margin through deep-imaging seismic interpretation and gravity modelling; Equatorial Guinea, West Africa. Tectonophysics, v.374(1–2), pp.19–40.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Choudhuri, M., Nemèok, M., Stuart, C. et al. 85°E Ridge, India — constraints on its development and architecture. J Geol Soc India 84, 513–530 (2014). https://doi.org/10.1007/s12594-014-0160-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12594-014-0160-9