@article{6af1a4e778484da8918eb4ae68dc51ca,
title = "Magnetic Mineralogical Approach for the Exploration of Gas Hydrates in the Bay of Bengal",
abstract = "We evaluate the environmental magnetic, geochemical, and sedimentological records from three sediment cores from potential methane-hydrate bearing sites to unravel linkages between sedimentation, shale tectonics, magnetite enrichment, diagenesis, and gas hydrate formation in the Krishna-Godavari basin. Based on downcore rock magnetic variations, four sedimentary magnetic property zones (I–IV) are demarcated. A uniform band of enhanced magnetic susceptibility (zone III) appears to reflect a period of high-sedimentation events in the Krishna-Godavari basin. Highly pressurized sedimentary strata developed as a result of increased sedimentation that triggered the development of a fault system that provided conduits for upward methane migration to enter the gas hydrate stability zone, leading to the formation of gas hydrate deposits that potentially seal the fault system. Magnetic susceptibility fluctuations and the presence of iron sulfides in a magnetically enhanced zone suggest that fault system growth facilitated episodic methane venting from deeper sources that led to multiple methane seepage events. Pyrite formation along sediment fractures resulted in diagenetic depletion of magnetic signals and potentially indicates paleo sulfate-methane transition zone positions. We demonstrate that a close correlation between magnetic susceptibility and chromium reducible sulfur concentration can be used as a proxy to constrain paleomethane seepage events. Our findings suggest that the interplay between higher sedimentation events and shale tectonism facilitated fluid/gas migration and trapping and the development of the gas hydrate system in the Krishna-Godavari basin. The proposed magnetic mineralogical approach has wider scope to constrain the understanding of gas hydrate systems in marine sediments.",
keywords = "Bay of Bengal, diagenesis, Krishna-Godavari basin, methane hydrates, rock magnetism, shale-tectonics",
author = "Firoz Badesab and Pawan Dewangan and Virsen Gaikwad and Myriam Kars and Muralidhar Kocherla and Krishna, \{Kolluru S.\} and Sangode, \{Satish J.\} and Kannan Deenadayalan and Pushpendra Kumar and Omkar Naikgaonkar and Mohammad Ismaiel and Aarbaz Khan",
note = "Funding Information: This study was funded by SERB-DST, Government of India, under the Early Career Research Award scheme (DST no. ECR/2016/000528) to F. B. The National Gas Hydrate Program coordinated by DGH is thanked for providing sediment samples from Indian National Gas Hydrate Expedition 01 for this study. We thank the Directors of CSIR-NIO, NIOT, NCAOR, advisor MOES, and NGHP (India) for supporting this work. We thank T. Ramprasad, A. Mazumdar, and S. Iyer for suggestions, Daryl Vaz for technical support, and Girish Prabhu and Areef Sardar for assistance with XRD and SEM-EDS analysis at CSIR-NIO. We also thank the Director, Indian Institute of Geomagnetism (IIG), New Panvel, for allowing specialized rock magnetic measurements. We thank the Director of the Center for Advanced Marine Core Research (CMCR), Kochi University, Japan for access to the Paleomagnetic laboratory during a research visit of FB through an INSA-JSPS fellowship. These analyses were supported by DST-JSPS under the scheme JSPS Postdoctoral Fellowship for Overseas Researchers (Strategic Program; JSPS grant GR 17202) and Establishment of Young Researcher Fellowship Programme 2017–2018 (IA/Indo-Japanese/F-1/2018) scheme awarded to F. B. We thank Chisa Nishimori and Yuhji Yamamoto for providing support in Kochi. The data are available on Mendeley Data repository (https://data.mendeley.com/). Figures S1, S2, and S3 are available in the supporting information. The authors declare no conflicts of interests. This is CSIR-NIO publication no. 6388. Funding Information: This study was funded by SERB‐DST, Government of India, under the Early Career Research Award scheme (DST no. ECR/2016/000528) to F. B. The National Gas Hydrate Program coordi nated by DGH is thanked for providing sediment samples from Indian National Gas Hydrate Expedition 01 for this study. We thank the Directors of CSIR‐ NIO, NIOT, NCAOR, advisor MOES, and NGHP (India) for supporting this work. We thank T. Ramprasad, A. Mazumdar, and S. Iyer for suggestions, Daryl Vaz for technical support, and Girish Prabhu and Areef Sardar for assistance with XRD and SEM‐EDS analysis at CSIR‐NIO. We also thank the Director, Indian Institute of Geomagnetism (IIG), New Panvel, for allowing specialized rock magnetic measurements. We thank the Director of the Center for Advanced Marine Core Research (CMCR), Kochi University, Japan for access to the Paleomagnetic laboratory during a research visit of FB through an INSA‐ JSPS fellowship. These analyses were supported by DST‐JSPS under the scheme JSPS Postdoctoral Fellowship for Overseas Researchers (Strategic Program; JSPS grant GR 17202) and Establishment of Young Researcher Fellowship Programme 2017–2018 (IA/ Indo‐Japanese/F‐1/2018) scheme awarded to F. B. We thank Chisa Nishimori and Yuhji Yamamoto for providing support in Kochi. The data are available on Mendeley Data reposi tory (https://data.mendeley.com/). Figures S1, S2, and S3 are available in the supporting information. The authors declare no conflicts of interests. This is CSIR‐NIO publication no. 6388. Publisher Copyright: {\textcopyright}2019. American Geophysical Union. All Rights Reserved.",
year = "2019",
month = may,
doi = "10.1029/2019JB017466",
language = "British English",
volume = "124",
pages = "4428--4451",
journal = "Journal of Geophysical Research: Solid Earth",
issn = "2169-9313",
publisher = "John Wiley and Sons Inc.",
number = "5",
}