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Title: | Rock magnetic evidence of tectonic control on the sedimentation and diagenesis in the Andaman Sea over ~1 million years |
Authors: | Badesab, F. Mascarenhas-Periera, M.B.L. Gaikwad, V. Dewangan, P. Panda, P.P. Deenadayalan, K. Salunke, K. Augastian, B. Patil, J.R. Lakshmi, B.V. |
Keywords: | Magnetic minerals Magnetic properties, Grain size, Inorganic geochemistry, Methane hydrates, Iron sulfide nodules |
Issue Date: | 2021 |
Citation: | Marine and Petroleum Geology, 130 (2021) 105150, https://doi.org/10.1016/j.marpetgeo.2021.105150 |
Abstract: | We evaluate the sedimentary (magnetic, mineralogical, geochemical, grain size) records of a long sediment core (NGHP-01-17 A) to elucidate the tectonic control on the sedimentation and diagenesis in the Andaman Sea (AS) over the past ~ 1 Ma. Two distinct sedimentary magnetic zones (Z-I and Z-II) are identified based on the rock magnetic signatures. A significant shift in the depositional environment is observed around ~90 ka which is marked by a rapid change in magnetite susceptibility (χlf), Fe, Ti and organic carbon content in Z-I. A trend of upward increase in χlf from ~90 ka to 3 ka in core NGHP-01-17 A suggest increase in detrital flux to the AS and represents the onset of a new sedimentary regime following most recent event of tectonic uplift in Indo-Burman Ranges (IBR) which occurred at ~ 150 ka. Methane influenced progressive diagenetic dissolution of detrital iron oxides and subsequent precipitation of iron sulfides in Z-II is clearly evident in the rock magnetic and mineralogical data. Multiple bands of diagenetically formed iron sulfide nodules at different periods in Z-II indicate episodic intensification of anaerobic oxidation of methane (AOM) due to enhanced methane-flux. We propose that fluid migration forced by tectonic processes facilitated episodic release of methane from deep reservoir that led to the formation of iron-sulfide nodules in the AS. |
URI: | http://library.iigm.res.in:8080/xmlui/handle/123456798/200 |
Appears in Collections: | SEG_Reprints |
Files in This Item:
File | Description | Size | Format | |
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DeenadayalanK-LaxmiBV_etal_Mar&PertoGeo_2021.pdf Restricted Access | 17.6 MB | Adobe PDF | View/Open Request a copy |
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