Sustained wood burial in the Bengal Fan over the last 19 My
Feakins, Sarah J.
MetadataShow full item record
The Ganges–Brahmaputra (G-B) River system transports over a billion tons of sediment every year from the Himalayan Mountains to the Bay of Bengal and has built the world’s largest active sedimentary deposit, the Bengal Fan. High sedimentation rates drive exceptional organic matter preservation that represents a long-term sink for atmospheric CO2. While much attention has been paid to organic-rich fine sediments, coarse sediments have generally been overlooked as a locus of organic carbon (OC) burial. However, International Ocean Discovery Program Expedition 354 recently discovered abundant woody debris (millimeter- to centimeter-sized fragments) preserved within the coarse sediment layers of turbidite beds recovered from 6 marine drill sites along a transect across the Bengal Fan (∼8°N, ∼3,700-m water depth) with recovery spanning 19 My. Analysis of bulk wood and lignin finds mostly lowland origins of wood delivered episodically. In the last 5 My, export included C4 plants, implying that coarse woody, lowland export continued after C4 grassland expansion, albeit in reduced amounts. Substantial export of coarse woody debris in the last 1 My included one wood-rich deposit (∼0.05 Ma) that encompassed coniferous wood transported from the headwaters. In coarse layers, we found on average 0.16 weight % OC, which is half the typical biospheric OC content of sediments exported by the modern G-B Rivers. Wood burial estimates are hampered by poor drilling recovery of sands. However, high-magnitude, low-frequency wood export events are shown to be a key mechanism for C burial in turbidites.
Author Posting. © National Academy of Sciences, 2019. This article is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 116(45), (2019): 22518-22525, doi:10.1073/pnas.1913714116.
Suggested CitationLee, H., Galy, V., Feng, X., Ponton, C., Galy, A., France-Lanord, C., & Feakins, S. J. (2019). Sustained wood burial in the Bengal Fan over the last 19 My. Proceedings of the National Academy of Sciences of the United States of America, 116 (45), 22518-22525.
Showing items related by title, author, creator and subject.
Ocean preconditioning of Cyclone Nargis in the Bay of Bengal : interaction between Rossby waves, surface fresh waters, and sea surface temperatures Yu, Lisan; McPhaden, Michael J. (American Meteorological Society, 2011-09)An in-depth data analysis was conducted to understand the occurrence of a strong sea surface temperature (SST) front in the central Bay of Bengal before the formation of Cyclone Nargis in April 2008. Nargis changed its ...
Submesoscale processes at shallow salinity fronts in the Bay of Bengal : observations during the winter monsoon Ramachandran, Sanjiv; Tandon, Amit; MacKinnon, Jennifer A.; Lucas, Andrew J.; Pinkel, Robert; Waterhouse, Amy F.; Nash, Jonathan D.; Shroyer, Emily L.; Mahadevan, Amala; Weller, Robert A.; Farrar, J. Thomas (American Meteorological Society, 2018-02-26)Lateral submesoscale processes and their influence on vertical stratification at shallow salinity fronts in the central Bay of Bengal during the winter monsoon are explored using high-resolution data from a cruise in ...
Intraseasonal rainfall variability in the Bay of Bengal during the Summer Monsoon : coupling with the ocean and modulation by the Indian Ocean Dipole Jongaramrungruang, Siraput; Seo, Hyodae; Ummenhofer, Caroline C. (John Wiley & Sons, 2017-01-24)The Indian Summer Monsoon rainfall exhibits pronounced intraseasonal variability in the Bay of Bengal (BoB). This study examines the intraseasonal rainfall variability with foci on the coupling with sea surface temperatures ...