| Title | High rates of organic carbon burial in submarine deltas maintained on geological timescales |
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| Author | Hage, S; Romans, B W ; Peploe, T G E; Poyatos-More, M; Haeri Ardakani, O; Bell, D; Englert, R G; Kaempfe, S A; Nesbit, P R; Sherstan, G;
Synnott, D P; Hubbard, S M |
| Source | Nature Geoscience 2022 p. 1-17, https://doi.org/10.1038/s41561-022-01048-4 |
| Image |  |
| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20220031 |
| Publisher | Nature Portfolio |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf; html |
| Subjects | general geology; Science and Technology; Nature and Environment; organic carbon |
| Illustrations | satellite imagery; diagrams; cross-plots; charts; photographs; tables |
| Program | Energy Geoscience Clean Energy Resources - Decreasing Environmental Risk |
| Released | 2022 10 24 |
| Abstract | Burial of terrestrial organic carbon in marine sediments can draw down atmospheric CO2 levels on Earth over geologic timescales (=105 yr). The largest sinks of organic carbon burial in present-day
oceans lie in deltas, which are composed of three-dimensional sigmoidal sedimentary packages called clinothems, dipping from land to sea. Analysis of modern delta clinothems, however, provides only a snapshot of the temporal and spatial
characteristics of these complex systems, making long-term organic carbon burial efficiency difficult to constrain. Here we determine the stratigraphy of an exhumed delta clinothem preserved in Upper Cretaceous (~75 million years ago) deposits in the
Magallanes Basin, Chile, using field measurements and aerial photos, which was then combined with measurement of total organic carbon to create a comprehensive organic carbon budget. We show that the clinothem buried 93 ± 19 Mt terrestrial-rich
organic carbon over a duration of 0.1-0.9 Myr. When normalized to the clinothem surface area, this represents an annual burial of 2.3-15.7 t km-2 yr-1 organic carbon, which is on the same order of magnitude as modern-day burial rates in clinothems
such as the Amazon delta. This study demonstrates that deltas have been and will probably be substantial terrestrial organic carbon sinks over geologic timescales, a long-standing idea that had yet to be quantified. |
| Summary | (Plain Language Summary, not published)
Burial of terrestrial organic carbon in marine sediments can draw down atmospheric CO2 levels on Earth over geologic timescales (=105 yr). This study
compared a comprehensive organic carbon budget for an exhumed ancient delta preserved in Upper Cretaceous (~75 Ma) deposits in the Magallanes Basin, Chile with modern deltas such as the Amazon delta to show the significance of burial of terrestrial
organic carbon in drawing down atmospheric CO2 levels. |
| GEOSCAN ID | 329984 |
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