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Processes Controlling Enrichment of Transition Elements in the Surficial Sediments of the Western Bay of Bengal


Affiliations
1 Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India
 

The processes leading to surficial enrichment of transition elements have been studied in continental slope and deep-sea sediments from the western Bay of Bengal (~500–4500 m water depth). The lower continental slope and rise (1800–3000 m) sediments are characterized by enrichment of Mn/Al ratios by 2–3 orders of magnitude and transition elements (Fe, Ni, Co, Cr and V) by a factor of 2–3 compared to the upper continental slope (500–1100 m) sediments. The occurrence of micronodules rich in Fe and Mn and elements associated with Mn-oxides, confirmed by scanning electron microscope and electron probe micro analysis, are responsible for the accumulation of transition elements in the lower continental slope sediments. The freshwater stratification, low carbonate productivity, fine grain size, low porosity, thin oxidized surficial layer and high sedimentation are conducive for diagenetic enrichment of Fe, Mn and elements associated with Mn-oxides in the lower slope sediments. The mid-depth oxygen minimum zone, resuspension and absence of oxidized surface layer enhance metal release to water column in the upper slope sediments. The oceanographic settings and high sedimentation rates control metal cycling in the Bay of Bengal sediments.

Keywords

Diagenesis, Fe–Mn Micronodules, Oxygen Minimum Zone, Sedimentation, Transition Elements.
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  • Hong, J., Calmano, W. and Förstner, U., Interstitial waters. In Trace Elements in Natural Waters (eds Salbu, B. and Steinnes, E.), CRC Press, Boca Raton, 1995, pp. 117–150.

  • Shaw, T. J., Gieskes, J. M. and Jahnke, R. A., Early diagenesis in differing depositional environments: the response of transition metals in pore water. Geochim. Cosmochim. Acta, 1990, 54, 1233–1246.

  • Burdige, D. J., The biogeochemistry of manganese and iron reduction in marine sediment. Earth Sci. Rev., 1993, 35, 249–284.

  • Sundby, B. and Silverberg, N., Manganese fluxes in the benthic boundary layer. Limnol. Oceanogr., 1985, 30, 374–382.

  • Stoffers, P., Glasby, G. P., Thijssen, T., Shrivastva, P. and Melguen, M., The geochemistry of coexisting manganese nodules, micronodules, sediments and pore waters from five areas in the equatorial and Southwest Pacific. Chem. Erde, 1981, 40, 273–297.

  • Kunzendorf, H., Glasby, G. P., Stoffers, P. and Renner, R. M., The distribution of rare earth elements in manganese nodules, micronodules and sediments along an east–west transect in the Southern Pacific. Lithos, 1989, 30, 45–56.

  • Pattan, J. N., Manganese micronodules: a possible indicator of sedimentary environments. Mar. Geol., 1993, 113, 331–344.

  • Pattan, J. N., Colley, S. and Higgs, N. C., Behavior of rare earth elements in coexisting manganese macronodules, micronodules and sediments from the central Indian Basin. Mar. Georesour. Geotechnol., 1994, 12, 283–295.

  • Lyle, M., The brown–green color transition in marine sediments: a marker of the Fe(III)–Fe(II) redox boundary. Limonol. Oceanogr., 1992, 28, 1026–1033.

  • Brumsack, H.-J., Geochemistry of recent TOC-rich sediments from The Gulf of California and the Black Sea. Geol. Rundsch., 1989, 78, 851–882.

  • Brumsack, H.-J., The trace metal content of recent organic carbon rich sediments: implications for Cretaceous black shale formation. Palaeogeogr., Palaeoclimatol., Palaeoecol., 2006, 232, 344–361.

  • Calvert, S. E. and Pedersen, T. F., Geochemistry of recent oxic and anoxic marine sediments: implications for the geological record. Mar. Geol., 1993, 113, 67–88.

  • Bhosle, N. B. and Dhople, V. M., Distribution of some biochemical compounds in the sediments of the Bay of Bengal. Chem. Geol., 1988, 67, 341–352.

  • Ittekot, V., The abiotically driven biological pump in the ocean and short term fluctuations in the atmospheric CO2 contents. Global Planet. Change, 1993, 8, 17–25.

  • Subramanian, V., Sediment load of Indian rivers. Curr. Sci., 1993, 64, 928–930.

  • Ramaswamy, V. and Nair, R. R., Fluxes of material in the Arabian Sea and Bay of Bengal-sediment trap studies. Proc. Indian Acad. Sci. (Earth Planet. Sci.), 1994, 103, 189–210.

  • Unger, D., Ittekot, V., Schafer, P. and Tiemann, J., Biogeochemistry of particulate organic matter from the Bay of Bengal as discernible from hydrolysable neutral carbohydrates and amino acids. Mar. Chem., 2005, 96, 155–184.

  • Prasad, T. G., Annual and seasonal mean buoyancy fluxes for the tropical Indian Ocean. Curr. Sci., 1997, 73, 667–674.

  • Prasanna Kumar, S. et al., Why is the Bay of Bengal less productive during summer monsoon compared to the Arabian Sea? Geophys. Res. Lett., 2002, 29(24), 88.1–88.4.

  • Ramaswamy, V. and Gaye, B., Regional variations in the fluxes of foraminifera carbonate, coccolithophorid carbonate and biogenic opal in the northern Indian Ocean. Deep-Sea Res. I, 2006, 53, 271–293.

  • Naqvi, S. W. A., Oxygen deficiency in the northern Indian Ocean. Suppl. Gayana, 2006, 70, 53–58.

  • Muller, C. and Gastner, M., The ‘Karbonat Bombe’ a simple device for the determination of the carbonate content in sediments, soils and other materials. Neu. Jb. Mineral. Mh., 1971, 10, 466–469.

  • Chauhan, O. S., Gujar, A. R. and Rao, Ch. M., On the occurrence of ferromanganese micronodules from the sediments of the Bengal Fan: a high terrigenous site. Earth Planet. Sci. Lett., 1994, 128, 563–573.

  • Chauhan, O. S. and Rao, Ch. M., Influence of sedimentation on enrichment of manganese and growth of ferromanganese micronodules, Bengal Fan, India. Mar. Geol., 1999, 161, 39–47.

  • Chauhan, O. S., Geochemistry of ferromanganese micronodules and associated Mn and trace metals diagenesis at high terrigenous depositional site of middle fan region, Bay of Bengal. Deep-Sea Res. II, 2003, 50, 961–978.

  • Klinkhammer, G., Heggie, D. T. and Graham, D. W., Metal diagenesis in oxic marine sediments. Earth Planet. Sci. Lett., 1982, 61, 211–219.

  • Dymond, J., Lyle, M., Finney, B., Piper, D. Z., Murphy, K., Conrad, R. and Pisias, N., Ferromanganese nodules from MANOP sites H, S, and R: control of mineralogical and chemical composition by multiple accretionary processes. Geochim. Cosmochim. Acta, 1984, 48, 93l–949.

  • Stoffers, P., Glasby, G. P. and Frenzel, G., Comparison of the characteristics of manganese micronodules from the equatorial and southwest Pacific. Tscher. Miner. Petrog., 1984, 33, 1–23.

  • Froelich, P. N. et al., Early oxidation of organic matter in pelagic sediments of the eastern and equatorial Atlantic: sub-oxic diagenesis. Geochim. Cosmochim. Acta, 1979, 43, 1075–1090.

  • Postma, D. and Jakobsen, R., Redox zonation: equilibrium constrains on the Fe(III)/SO4-reduction interface. Geochim. Cosmochim. Acta, 1996, 60, 3169–3175.

  • Lynn, D. C. and Bonatti, E., Mobility of manganese in diagenesis of deep sea sediments. Mar. Geol., 1965, 3, 457–474.

  • Chakraborty, P., Chakraborty, S., Jayachandran, S., Madan, R., Sarkar, A., Linsy, P. and Nagender Nath, B., Effects of bottom water dissolved oxygen variability on copper and lead fractionation in the sediments across the oxygen minimum zone, western continental margin of India. Sci. Total Environ., 2016, 556, 1052–1061.

  • Pattan, J. N., Parthiban, G., Prakash Babu, C., Khadge, N. H., Paropkari, A. L. and Kodagali, V. N., A note on geochemistry of surface sediments from Krishna–Godavari basin, east coast of India. J. Geol. Soc. India, 2008, 71, 107–114.

  • Prakash Babu, C. and Ramaswamy, V., Phosphorus accumulation associated with intense diagenetic metal-oxide cycling in sediments along the eastern continental margin of India. Curr. Sci., 2017, 113(3), 473–478.

  • Burns, R. G. and Burns, V. M., Authigenic oxides. In The Sea, Volume 7, The Oceanic Lithosphere (ed. Emiliani, C.), WileyInterscience, New York, USA, 1981, pp. 875–914.

  • Balistrieri, L. S. and Murray, J. W., The surface chemistry of sediments from the Panama Basin: the influence of Mn oxides on metal adsorption. Geochim. Cosmochim. Acta, 1986, 50, 2235–2243.

  • Subramanian, V., ‘T Dack, L. V. and Grieken, R. V., Chemical composition of river sediments from the Indian sub-continent. Chem. Geol., 1985, 48, 271–279.


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  • Processes Controlling Enrichment of Transition Elements in the Surficial Sediments of the Western Bay of Bengal

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Authors

C. Prakash Babu
Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India
V. Ramaswamy
Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India

Abstract


The processes leading to surficial enrichment of transition elements have been studied in continental slope and deep-sea sediments from the western Bay of Bengal (~500–4500 m water depth). The lower continental slope and rise (1800–3000 m) sediments are characterized by enrichment of Mn/Al ratios by 2–3 orders of magnitude and transition elements (Fe, Ni, Co, Cr and V) by a factor of 2–3 compared to the upper continental slope (500–1100 m) sediments. The occurrence of micronodules rich in Fe and Mn and elements associated with Mn-oxides, confirmed by scanning electron microscope and electron probe micro analysis, are responsible for the accumulation of transition elements in the lower continental slope sediments. The freshwater stratification, low carbonate productivity, fine grain size, low porosity, thin oxidized surficial layer and high sedimentation are conducive for diagenetic enrichment of Fe, Mn and elements associated with Mn-oxides in the lower slope sediments. The mid-depth oxygen minimum zone, resuspension and absence of oxidized surface layer enhance metal release to water column in the upper slope sediments. The oceanographic settings and high sedimentation rates control metal cycling in the Bay of Bengal sediments.

Keywords


Diagenesis, Fe–Mn Micronodules, Oxygen Minimum Zone, Sedimentation, Transition Elements.

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DOI: https://doi.org/10.18520/cs%2Fv114%2Fi10%2F2161-2167