@article {49,
	title = {Pore-water chemistry of sediment cores off Mahanadi Basin, Bay of Bengal: Possible link to deep seated methane hydrate deposit},
	journal = {Marine and Petroleum Geology},
	volume = {49},
	year = {2014},
	pages = {162-175},
	abstract = {Organoclastic degradation and anaerobic oxidation of methane (AOM) are known to influence sulfate, methane and bicarbonate concentrations of sediment pore-waters. In this work we have analyzed the pore-fluid composition of three piston cores (36{\textendash}39 m long) collected from water depths ranging from 1429 to 1691 m. We attribute the observed linear sulfate concentration profiles and (ΔCa + ΔAlk)/ΔSO42- ratios dominantly to anaerobic oxidation of methane (AOM) induced sulfate consumption. The gas rich layers just below the base of hydrate stability zone (BGHSZ) is the possible source of the enhanced diffusive flux of biogenic methane ( δ 13 C CH 4 ranging from -99.7 to -106.3{\textperthousand} VPDB). Occurrences of disseminated gas hydrate in the Mahanadi Basin within the hydrate stability zone (210{\textendash}220 m thick) supports the link between linear sulfate profile, high rate of AOM and hydrate occurrence.},
	issn = {0264-8172},
	doi = {10.1016/j.marpetgeo.2013.10.011},
	url = {http://www.sciencedirect.com/science/article/pii/S0264817213002638},
	author = {Mazumdar, A. and Peketi, A. and Joao, H. M. and Dewangan, P. and Ramprasad, T.}
}
@article {146,
	title = {Geochemical and geological constraints on the composition of marine sediment pore fluid: Possible link to gas hydrate deposits},
	journal = {Marine and Petroleum Geology},
	volume = {38},
	year = {2012},
	note = {id: 2306},
	pages = {35-52},
	abstract = {Pore water sulfate consumption in marine sediments is controlled by microbially driven sulfate reduction via organo-clastic and methane oxidation processes. In this work, we present sediment pore fluid compositions of 10 long sediment cores and high resolution seismic data from the Krishna{\textendash}Godavari (K{\textendash}G) basin, Bay of Bengal. Our results show occurrence of transient (S and kink types) and steady state (quasi-linear) sulfate concentration profiles which are attributed partly to the anaerobic oxidation of methane ( δ 13 C CH 4 : -84.8 to -100.1{\textperthousand} VPDB) and organo-clastic sulfate reduction. Influence of AOM on alkalinity is evident from the presence of authigenic carbonate layers with highly depleted carbon isotope ratios in core MD161-8. The authigenic carbonates represent the paleo-SMTZs and suggest marked fluctuation in vertical methane flux. Our geophysical data show the acoustic signatures of upward fluid migration from shallow sub-surface, whereas, coring during NGHP expedition-01 confirms the presence of sub-surface gas hydrate deposits in K{\textendash}G basin which can be linked to deep methane sources. The geochemical analysis suggests that shallow methane source can be attributed to high burial flux of labile organic matter due to high sedimentation rate. Sampling sites with high methane flux from the shallow gas source are characterized by quasi-linear sulfate concentration profile and a shallow sulfate methane transition zone (SMTZ) and may not be necessarily linked to deeper gas hydrate deposits. In contrast, the deep methane source results in a transient kink type sulfate profile and a deeper SMTZ. We have observed a close link between the occurrence of gas hydrate and the S/kink type sulfate profile. We interpret the short lived {\textquoteleft}kink{\textquoteright} in the sulfate profiles as a result of recent enhancement in vertical methane flux possibly driven by reactivation of fault-fractures systems which provide the conduits for fluid flow.},
	issn = {0264-8172},
	doi = {10.1016/j.marpetgeo.2012.07.004},
	url = {http://www.sciencedirect.com/science/article/pii/S0264817212001808},
	author = {Mazumdar, A. and Joao, H. M. and Peketi, A. and Dewangan, P. and Kocherla, M. and Joshi, R. K. and Ramprasad, T.}
}
@article {252,
	title = {Evidence of paleo-cold seep activity from the Bay of Bengal, offshore India},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {10},
	year = {2009},
	note = {id: 794; 458FC Times Cited:0 Cited References Count:80Y},
	abstract = {We report evidence of paleo-cold seep associated activities, preserved in methane-derived carbonates in association with chemosynthetic clams (Calyptogena sp.) from a sediment core in the Krishna-Godavari basin, Bay of Bengal. Visual observations and calculations based on high-resolution wet bulk density profile of a core collected on board R/V Marion Dufresne (May 2007) show zones of sharp increase in carbonate content (10-55 vol\%) within 16-20 meters below seafloor (mbsf). The presence of Calyptogena clam shells, chimneys, shell breccias with high Mg calcite cement, and pyrite within this zone suggest seepage of methane and sulfide-bearing fluid to the seafloor in the past. Highly depleted carbon isotopic values (delta C-13 ranges from -41 to -52\% VPDB) from these carbonates indicate carbon derived via anaerobic oxidation of methane. Extrapolated mean calendar age (similar to 58.7 ka B. P.) of the clastic sediments at a depth of 16 mbsf is close to the upper limit of the U-Th based depositional age (46.2 +/- 3.7 and 53.0 +/- 1.6 ka) of authigenic carbonates sampled from this level, thereby constraining the younger age limit of the carbonate deposition/methane expulsion events. The observed carbonate deposition might have resulted from the flow of methane-enriched fluids through the fracture network formed because of shale diapirism.},
	issn = {1525-2027},
	doi = {10.1029/2008gc002337},
	author = {Mazumdar, A. and Dewangan, P. and Joao, H. M. and Peketi, A. and Khosla, V. R. and Kocherla, M. and Badesab, F. K. and Joshi, R. K. and Roxanne, P. and Ramamurty, P. B. and Karisiddaiah, S. M. and Patil, D. J. and Dayal, A. M. and Ramprasad, T. and Hawkesworth, C. J. and Avanzinelli, R.}
}
