U. Böker
Microbial cycling, migration and leakage of light alkanes in the Nile Delta tertiary fan
Böker, U.; Dodd, T.A.; Goldberg, T.; Aplin, A.C.
Abstract
We present a geochemical dataset which helps unravel the complex set of processes by which light alkanes are sourced, charged, mixed, leaked and altered in the Plio-Pleistocene Nile Delta. Thermogenic gas derives from a sub-Messinian source and mixes with microbial, hydrogenotrophic, methane-rich gas in the Plio-Pleistocene section. There is strong isotopic evidence for both microbial generation and microbial degradation of ethane and propane, but these signals are only recorded where the rates of biological processes outstrip the rate of thermogenic charge. High resolution gas geochemistry profiles through four, 500–1100 m sequences of mixed channel, channel levee, mass flow deposits and hemipelagites shed light on migration and leakage pathways. We see limited geochemical evidence for migration along or across faults which cross-cut mud-rich sequences. Lateral migration along sands/silts delivers gas to structural highs, where leakage occurs vertically along focussed pathways through heterogeneous mud-rich sediments. We propose that in situ generation of microbial gas within mud-rich sequences facilitates percolation of migrating gases that replenishes C2+ components and sustains the biodegradation pathway in syntrophic microbial communities. High resolution changes in gas composition suggest an unequilibrated system which is being actively charged. In some structures, rates of charge and of microbial alteration of gas are broadly similar; in others, rates of charge exceed rates of microbial alteration. Our results have important implications for the understanding of both basin-wide fluid flow and the ecology of the deep biosphere.
Citation
Böker, U., Dodd, T., Goldberg, T., & Aplin, A. (2020). Microbial cycling, migration and leakage of light alkanes in the Nile Delta tertiary fan. Marine and Petroleum Geology, 121, Article 104578. https://doi.org/10.1016/j.marpetgeo.2020.104578
Journal Article Type | Article |
---|---|
Acceptance Date | Jul 2, 2020 |
Online Publication Date | Jul 16, 2020 |
Publication Date | 2020-11 |
Deposit Date | Jul 17, 2020 |
Publicly Available Date | Jul 16, 2021 |
Journal | Marine and Petroleum Geology |
Print ISSN | 0264-8172 |
Electronic ISSN | 1873-4073 |
Publisher | Elsevier |
Peer Reviewed | Peer Reviewed |
Volume | 121 |
Article Number | 104578 |
DOI | https://doi.org/10.1016/j.marpetgeo.2020.104578 |
Public URL | https://durham-repository.worktribe.com/output/1297810 |
Files
Accepted Journal Article
(8.3 Mb)
PDF
Publisher Licence URL
http://creativecommons.org/licenses/by-nc-nd/4.0/
Copyright Statement
© 2020 This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
You might also like
1D Hydro-geomechanical Modelling of Pore Pressure on an Active Convergent Margin: East Coast Basin, New Zealand
(2023)
Presentation / Conference Contribution
Downloadable Citations
About Durham Research Online (DRO)
Administrator e-mail: dro.admin@durham.ac.uk
This application uses the following open-source libraries:
SheetJS Community Edition
Apache License Version 2.0 (http://www.apache.org/licenses/)
PDF.js
Apache License Version 2.0 (http://www.apache.org/licenses/)
Font Awesome
SIL OFL 1.1 (http://scripts.sil.org/OFL)
MIT License (http://opensource.org/licenses/mit-license.html)
CC BY 3.0 ( http://creativecommons.org/licenses/by/3.0/)
Powered by Worktribe © 2024
Advanced Search