Current Science

Open Access Open Access  Restricted Access Subscription Access

Origin and Distribution of Shallow Gas-Charged Sediment on the Inner Continental Shelf of Central West Coast of India


Affiliations
1 CSIR-National Institute of Oceanography, Dona-Paula, Goa 403 004, India
2 CSIR-National Institute of Oceanography, Regional Centre, Andheri (W), Mumbai 400 053, India
 

High-resolution shallow seismic investigations on inner continental shelf of Goa have been carried out to map gas-charged sediment zones and investigate origin of trapped gas. Analyses of data reveal that the gas is trapped by different stratigraphic layers and is distributed in two zones. Zone-1 is restricted up to ~30 m water depth and in the southern part of the study area. In this zone, gas is confined within the Holocene layers above the Holocene maximum Hooding surface (MFS). Whereas, zone-2 is comprised of several isolated gas-charged patches which are distributed in the entire study area mostly between ~20 m and ~45 m water depth. In this zone, gas is confined below Holocene- MFS in incised river bed or a layer just below MFS or both. Gas-charged sediment in zone-1 is formed due to degradation of organic material which is predominantly early Holocene mangrove derived, whereas, zone-2 it is formed due to degradation of organic material which were deposited by ancestral rivers during the post-glacial sea level rise of the Late Pleistocene. The distribution pattern of zone-1 is controlled by coastline configuration, long-term longshore current pattern, Holocene rapid sea level rise and lithological character of exposed inter-tidal zone. Whereas, distribution of zone-2 is controlled by palaeo-rivers of different glacial periods and their hydraulic energy condition during the base level rise.

Keywords

Acoustic Blanking, Acoustic Turbidity, Central West Coast of India, Gas-Charged Sediment, Mangrove, Shallow Seismic.
User
Notifications
Font Size

  • Hinrichs, K. and Boetius, A., The anaerobic oxidation of methane: new insights in microbial ecology and biogeochemistry. In Ocean Margin Systems (eds Wefer, G. et al.), Springer-Verlag, Berlin, Heidelberg, 2002, pp. 457–477.

  • Dekas, A. E., Poretsky, R. S. and Orphan, V. J., Deep-sea archaea fix and share nitrogen in methane-consuming microbial consortia. Science, 2009, 326, 422–426; doi:10.1126/science.1178223.

  • Boetius, A. and Wenzhoefer, F., Seafloor oxygen consumption fuelled by methane from cold seeps. Nat. Geosci., 2013, 6, 725– 734; doi:10.1038/ngeo1926.

  • Best, A. I., Tuffin, M. D. J., Dix, J. K. and Bull, J. M., Tidal height and frequency dependence of acoustic velocity and attenuation in shallow gassy marine sediments. J. Geophys. Res., Solid Earth, 2004, 109(B8), 101.

  • Judd, A., Davies, G., Wilson, J., Holmes, R., Baron, G. and Bryden, I., Contributions to atmospheric methane by natural gas seepage on the UK continental shelf. Mar. Geol., 1997, 137, 165– 189.

  • Premchitt, J., Rad, N. S., To, P., Shaw, R. and James, J. W. C., A study of gas in marine sediments in Hong Kong. Cont. Shelf Res., 1992, 12(10), 1251–1264.

  • Garcia-Gil, S., Vilas, F. and Garcia-Garcia, A., Shallow gas features in incised-valley fills (Ria de Vigo, NW Spain): a case study. Cont. Shelf Res., 2002, 22(16), 2303–2315.

  • Hovland, M. and Judd, A. G., The global production of methane from shallow submarine sources. Cont. Shelf Res., 1992, 12(10), 1231–1238.

  • Siddiquie, H. N., Rao, D. G., Vora, K. H. and Topgi, R. S., Acoustic masking in sediments due to gases on the western continental shelf of India. Mar. Geol., 1980, 39, 27–37.

  • Rao, P. S., Sonograph patterns of the central western continental shelf of India. J. Coast. Res., 1989, 5–4, 725–736.

  • Karisiddaiah, S. M., Veerayya, M., Vora, K. H. and Wagle, B. G., Gas charged sediments on the inner continental shelf off western India. Mar. Geol., 1992, 1(l0), 143–152.

  • Karisiddaiah, S. M. and Veerayya, M., Methane-bearing shallow gas-charged sediments in the eastern Arabian Sea: a probable source for greenhouse gas. Cont. Shelf Res., 1994, 14(12), 1361– 1370.

  • Mazumdar, A. et al., Shallow gas-charged sediments off the Indian west coast: Genesis and distribution. Mar. Geol., 2009, 267, 71–85.

  • Wagle, B. G., Vora, K. H., Karisiddaiah, S. M., Veerayya, M. and Almeida, F., Holocene submarine terraces on the western continental shelf of India: implications for sea-level changes. Mar. Geol., 1994, 117, 207–225.

  • Karisiddaiah, S. M., Veerayya, M. and Vora, K. H., Seismic and sequence stratigraphy of the central western continental margin of India: late-Quaternary evolution. Mar. Geol., 2002, 192, 335–353.

  • Dubey, K. M., Chaubey, A. K., Mahale, V. P. and Karisiddaiah, S. M., Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: a case study from the west coast of India. Geosci. Front., 2018; https://doi.org/10.1016/j.gsf.2018.09.016.

  • Krishna, K. S., Rao, D. G., Murty, G. P. S. and Ramana, Y. V., Sound velocity, density, and related properties along a transect across the Bay of Bengal. Geol. Mar. Lett., 1989, 9, 95–102.

  • Floodgate, G. D. and Judd, A. D., The origin of shallow gas. Cont. Shelf Res., 1992, 12, 1145–1156.

  • Megonigal, J. P., Hines, M. E. and Visscher, P. T., Anaerobic metabolism: linkages to trace gases and aerobic processes. In Treatise on Geochemistry: Biogeochemistry (eds Holland, H. D. and Turekian, K. K.), Elsevier Pergamon, 2003, vol. 8, pp. 317– 424.

  • Canfield, D. E., Kristensen, E. and Thamdrup, B., Aquatic geomicrobiology. Adv. Mar. Biol., 2005, 48, 638.

  • Reeburgh, W. S., Oceanic methane biogeochemistry. Chem. Rev., 2007, 107, 486–513.

  • Judd, A. G. and Hovland, M., Seabed Fluid Flow: Impact on Geology, Biology and the Marine Environment, Cambridge University Press, New York, 2007.

  • Fleischer, P., Orsi, T. H., Richardson, M. D. and Anderson, A. L., Distribution of free gas in marine sediments: a global overview. Geo. Mar. Lett., 2001, 21, 103–122.

  • Hashimi, N. H., Nigam, R., Nair, R. R. and Rajagopalan, G., Holocene sea-level fluctuations on western Indian continental margin: an update. J. Geol. Soc. India, 1995, 46, 157–162.

  • Woodroffe, C. D., Development of mangrove forests from a geological perspective. In Biology and Ecology of Mangroves. Tasks for Vegetation Science (ed. Teas, H. J.), Springer, Dordrecht, 1983, p. l–17; https://doi.org/10.1007/978-94-017-0914-9_1.

  • Mascarenhas, A., Significance of peat on the western continental shelf of India. J. Geol. Soc. India, 1997, 49, 145–152.

  • Pandarinath, K., Shankar, R. and Yadava, M. G., Late Quaternary changes in sea level and sedimentation rate along the SW coast of India: evidence from radiocarbon dates. Curr. Sci., 2001, 81(5), 594–600.


Abstract Views: 300

PDF Views: 139




  • Origin and Distribution of Shallow Gas-Charged Sediment on the Inner Continental Shelf of Central West Coast of India

Abstract Views: 300  |  PDF Views: 139

Authors

K. M. Dubey
CSIR-National Institute of Oceanography, Dona-Paula, Goa 403 004, India
A. K. Chaubey
CSIR-National Institute of Oceanography, Regional Centre, Andheri (W), Mumbai 400 053, India

Abstract


High-resolution shallow seismic investigations on inner continental shelf of Goa have been carried out to map gas-charged sediment zones and investigate origin of trapped gas. Analyses of data reveal that the gas is trapped by different stratigraphic layers and is distributed in two zones. Zone-1 is restricted up to ~30 m water depth and in the southern part of the study area. In this zone, gas is confined within the Holocene layers above the Holocene maximum Hooding surface (MFS). Whereas, zone-2 is comprised of several isolated gas-charged patches which are distributed in the entire study area mostly between ~20 m and ~45 m water depth. In this zone, gas is confined below Holocene- MFS in incised river bed or a layer just below MFS or both. Gas-charged sediment in zone-1 is formed due to degradation of organic material which is predominantly early Holocene mangrove derived, whereas, zone-2 it is formed due to degradation of organic material which were deposited by ancestral rivers during the post-glacial sea level rise of the Late Pleistocene. The distribution pattern of zone-1 is controlled by coastline configuration, long-term longshore current pattern, Holocene rapid sea level rise and lithological character of exposed inter-tidal zone. Whereas, distribution of zone-2 is controlled by palaeo-rivers of different glacial periods and their hydraulic energy condition during the base level rise.

Keywords


Acoustic Blanking, Acoustic Turbidity, Central West Coast of India, Gas-Charged Sediment, Mangrove, Shallow Seismic.

References





DOI: https://doi.org/10.18520/cs%2Fv116%2Fi8%2F1410-1417