Abstract
The Afanasy Nikitin seamount (ANS) is a major structural feature (400 km-long and 150 km-wide) in the Central Indian Basin, situated at the southern end of the so-called 85°E Ridge. Combined analyses of new multibeam bathymetric, seismic reflection and geochronological data together with previously described magnetic data provide new insights into the growth of the ANS through time, and its relationship with the 85°E Ridge. The ANS comprises a main plateau, rising 1200 m above the surrounding ocean floor (4800 m), and secondary elevated seamount highs, two of which (lie at 1600 and 2050 m water depths) have the morphology of a guyot, suggesting that they were formed above or close to sea-level. An unbroken sequence of spreading anomalies 34 through 32n.1 identified over the ANS reveal that the main plateau of the ANS was formed at 80–73 Ma, at around the same time as that of the underlying oceanic crust. The 40Ar/39Ar dates for two basalt samples dredged from the seamount highs are consistent, within error, at 67 Ma. These results, together with published results of late Cretaceous to early Cenozoic Indian Ocean plate reconstructions, indicate that the Conrad Rise hotspot emplaced both the main plateau of the ANS and Conrad Rise (including the Marion Dufresne, Ob and Lena seamounts) at 80–73 Ma, close to the India–Antarctica Ridge system. Subsequently, the seamount highs were formed by late-stage volcanism c. 6–13 Myr after the main constructional phase of the seamount plateau. Flexural analysis indicates that the main plateau and seamount highs of the ANS are consistent with Airy-type isostatic compensation, which suggest emplacement of the entire seamount in a near spreading-center setting. This is contrary to the flexural compensation of the 85°E Ridge further north, which is interpreted as being emplaced in an intraplate setting, i.e., 25–35 Myr later than the underlying oceanic crust. Therefore, we suggest that the ANS and the 85°E Ridge appear to be unrelated as they were formed by different mantle sources, and that the proximity of the southern end of the 85°E Ridge to the ANS is coincidental.
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References
Banakar V K, Pattan J N and Mudholkar A V 1997 Paleoceanographic conditions during the formation of a ferromanganese crust from the Afanasy–Nikitin seamount, north central Indian Ocean: Geochemical evidence; Mar. Geol. 136 299–315.
Bull J M 1990 Structural style of intraplate deformation, central Indian Ocean Basin: Evidence for the role of fracture zones; Tectonophys. 184 213–228.
Bull J M 1990 Structural style of intraplate deformation, central Indian Ocean Basin: Evidence for the role offracture zones; J. Geol. Soc. London 149 955–966.
Borisova A Yu, Nikulin V V, Belyatsky B V, Ovchinnikova G V, Lewskii L K and Sushvhevskaya N M 1996 Late alkaline lavas of the Ob and Lena Seamounts (Conrad Rise, Indian Ocean): Geochemistry and characterisation of mantle sources; Geochem. Int. 34 503–517 (in Russian).
Borisova A Yu, Belyatsky B V, Portnyagin M V and Sushchevskaya N M 2001 Petrogenesis of Olivine-phyric Basalts from the Aphanasey Niktitin Rise: Evidence for contamination by Cratonic Lower Continental Crust; J. Petrol. 42 277–319.
Cande S 780 C and Kent D V 1995 Revised calibration of the geomagnetic polarity time scale for the Late Cretaceous and Cenozoic; J. Geophys. Res. 100 6093–6095, doi:10.1029/94JB03098.
Curray J R and Munasinghe T 1991 Origin of the Rajmahal Traps and the 85◦E Ridge: Preliminary reconstructionsof the trace of the Crozet hotspot; Geology 19 1237–1240.
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: The Ocean Basins and Margins, The Indian Ocean (eds) Nairn A E and Stehli F G, Plenum, New York, 6 399–450.
Diament M and Goslin J 1986 Emplacement of the Marion Dufresne, Lena and Ob seamounts (South Indian Ocean) from a study of isostasy; Tectonophys. 121 253–262.
Fleck R J, Sutter J F, and Elliot D H 1977 Interpretation of discordant 40Ar/39Ar age-spectra of Mesozoic tholeiites from Antarctica; Geochim. Cosmochim. Acta 41 15–32.
Garcia M O, Swinnard L, Weis D, Greene A, Tagami T, Sano H and Gandy C 2010 Petrology, geochemistry and geochronology of Kaua‘i Lavas over 4.5 Myr: Implications for the origin of rejuvenated volcanism and the evolution of the Hawaiian plume; J. Petrol. 51 (2010), 1507–1540.
Geist D, Diefenbach B A, Fornari D J, Kurz M D, Harpp K and Blusztajn J 2008 Construction of the Gala’pagos platform by large submarine volcanic terraces; Geochem. Geophys. Geosys. 9 Q03015, doi:10.1029/2007GC001795.
Gopala Rao D, Krishna K S and Sar D 1997 Crustal evolution and sedimentation history of the Bay of Bengal since the Cretaceous; J. Geophys. Res. 102 17,747–17,768.
Ishizuka O, Yuasa M, Taylor R N and Sakamoto I 2009 Two contrasting magmatic types coexist after the cessation of back-arc spreading; Chem. Geol. 266 283–305.
Karner G D and Weissel J K 1990 Compressional deformation of oceanic lithosphere in the central indian Ocean: Why it is, where it is; In: Proc. Ocean Drilling Program (eds) Cochran J R, Stow D A V et al., Sci. Results, College Station, Texas, Ocean Drilling Program, 116 279–289.
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, Rao M 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.
Krishna K S and Gopala Rao D 2000 Abandoned Paleocene spreading center in the northeastern Indian Ocean: Evidence from magnetic and seismic reflection data; Mar. Geol. 162 215–224.
Krishna K S, Bull J M and Scrutton R A 2001 Evidence for multiphase folding of the central Indian Ocean lithosphere; Geology 29 715–718.
Krishna K S 2003 Structure and evolution of the Afanasy Nikitin seamount, buried hills and 85°E Ridge in the northern Indian Ocean; Earth Planet. Sci. Lett. 209 379–394.
Krishna K S, Michael L, Bhattacharyya R and Majumdar T J 2009a Geoid and gravity anomaly data of conjugate regions of Bay of Bengal and Enderby Basin – new constraints on breakup and early spreading history between India and Antarctica; J. Geophys. Res. 114 B03102, DOI doi:10.1029/2008JB005808.
Krishna K S, Bull J M and Scrutton R A 2009b Early (pre-8 Ma) fault activity and temporal strain distribution in the central Indian Ocean; Geology 37 227–230.
Krishna K S, Abraham H, Sager W W, Pringle M, Frey F A, Gopala Rao D and Levchenko O V 2012 Tectonics of the Ninetyeast Ridge derived from the spreading records of the contiguous oceanic basins and age constraints of the ridge; J. Geophys. Res. 117, doi:10.1029/2011JB008805.
Liu C S, Curray J R and McDonald J M 1983 New constraints on the tectonic evolution of the Eastern Indian Ocean; Earth Planet. Sci. Lett. 65 331–342.
Mahoney J J, White W M, Upton B G J, Neal C R and Scrutton R A 1996 Beyond EM-1: Lavas from Afanasy–Nikitin Rise and the Crozet Archipelago, Indian Ocean; Geology 24 (1996), 615–618.
Michael L and Krishna K S 2011 Dating of the 85°E Ridge (northeastern Indian Ocean) using marine magnetic anomalies; Curr. Sci. 100 1314–1322.
Müller R D, Royer J-Y, and Lawver L A Revised plate motions relative to the hotspots from combined Atlantic and Indian Ocean hotspot tracks; Geology 21 275–278.
O’Neill C, Müller R D, and Steinberger B 2003 Geodynamic implications of moving Indian Ocean hotspots; Earth Planet. Sci. Lett. 215 151–168.
Paul J, Singh R N, Subrahmanyam C, and Drolia R K 1990 Emplacement of Afanasy–Nikitin seamount based on transfer function analysis of gravity and bathymetry data; Earth Planet. Sci. Lett. 96 419–426.
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; Tectonophys. 155 261–283.
Radhakrishna M, Srinivasa Rao G, Nayak S, Bastia R, and Twinkle D 2012 Early Cretaceous fracture zones in the Bay of Bengal and their tectonic implications: Constraints from multi-channel seismic reflection and potential field data; Tectonophys. 522–523 187–197.
Redbourn L J, Bull J M, Scrutton R A and Stow D A V 1993 Channels, echo character mapping and tectonics from 3.5 kHz profiles, distal Bengal Fan; Mar. Geol. 114 155–170.
Royer J-Y and Sandwell D T 1989 Evolution of the eastern Indian Ocean since the Late Cretaceous: Constraints from Geosat Altimetry; J. Geophys. Res. 94 13,755–13,782.
Royer J-Y, Peirce J W and Weissel J K 1991 Tectonic constraints on the hot-spot formation of Ninetyeast Ridge; In: Proc. ODP, Sci. Results, College Station, Texas, Ocean Drilling Program, 121 763-776.
Sborshchikov I M, Murdmaa I O, Matveenkov V V, Kashintsev G L, Glomshtock A I and Al’mukhamedov A I 1995 Afanasy Nikitin seamount within the intraplate deformation zone, Indian Ocean; Mar. Geol. 128 115–126.
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 modeling approach; J. Earth Syst. Sci 120 605–615.
Steiger R H and E Jäger E 1977 Subcommision on geochronology: Convention on the use of decay constants in geo- and cosmochronology; Earth Planet. Sci. Lett. 36 359–362.
Uchiumi S and Shibata K 1980 Errors in K–Ar age determination; Bull. Geol. Surv. Japan 31 267–273 (in Japanese with English abstract).
York D 1969 Least squares fitting of a straight line with correlated errors; Earth Planet. Sci. Lett. 5 320–324.
Acknowledgements
KSK thanks the Royal Society for their award of a RS–CSIR Fellowship to support this research at the National Oceanography Centre, Southampton and at the University of Edinburgh. OI greatly appreciates JSPS for supporting a Japan–UK joint research program. The authors thank M Narui and M Yamazaki, International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University for providing opportunities of neutron irradiation of samples at the JRR3 reactor. They also thank K Yamanobe for assistance with geochemical analyses and are grateful to the Ministry of Earth Sciences, India for the support extended for the acquisition of multibeam bathymetry and other oceanographic data over the ANS. This is NIO contribution number 5416.
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Appendix
Laser step-heating experiments were conducted on 22 mg of plagioclase separates in case of sample AFNCD28fd and 11.4 mg of ground-mass separate for sample CC2/ADR24. Due to weak alteration in poorly-crystallized part of ground-mass, samples were treated at 100°C on hot plate with stirrer in 6N HCl for 60 min and then 6N HNO3 for 60 min in order to eliminate possible alteration products (clays and carbonates) prior to irradiation. After this acid treatment, these separates were examined under binocular microscope before being packed for irradiation. Sample irradiation was done at the JRR3 reactor of Japan Atomic Energy Agency. Fast neutron fluxes were about 1.4–1.7 × 1012 n/cm2 · s. Sanidine separated from the Fish Canyon Tuff (FC3) was used for the flux monitor and assigned an age of 27.5 Ma, which has been determined against our primary standard for our K–Ar laboratory, Sori biotite, whose age is 91.2 Ma ((Uchiumi and Shibata 1980).
CO2 laser (NEWWAVE MIR10-30) equipped with a faceted lens was used for sample heating. Argon isotopes were measured on a VG Isotech VG3600 noble gas mass spectrometer fitted with a BALZERS electron multiplier. Correction for interfering isotopes was achieved by analyses of CaFeSi 2O6 and KFeSiO4 glasses irradiated with the samples. The blank of the system including the mass spectrometer and the extraction line was 7.5 × 10−14 ml STP for 36Ar, 2.5 × 10−13 ml STP for 37Ar, 2.5 × 10−13 ml STP for 38Ar, 1.0 × 10−12 ml STP for 39Ar and 2.5 × 10−12 ml STP for 40 Ar. The blank analysis was done every 2 or 3 step analyses.Errors for ages include analytical uncertainties for Ar isotope analysis, correction for interfering isotopes and J value estimation. An error of 0.5% was assigned to J values as a pooled estimate during the course of this study. Plateau ages were calculated as weighted means of ages of plateau-forming steps, where each age was weighted by the inverse of its variance. The age plateaus were determined following the definition by Fleck et al. (1977). Inverse isochrons were calculated using York’s least-squares fit, which accommodates errors in both ratios and correlations of errors (York 1969).
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KRISHNA, K.S., BULL, J.M., ISHIZUKA, O. et al. Growth of the Afanasy Nikitin seamount and its relationship with the 85°E Ridge, northeastern Indian Ocean. J Earth Syst Sci 123, 33–47 (2014). https://doi.org/10.1007/s12040-013-0392-x
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DOI: https://doi.org/10.1007/s12040-013-0392-x