Controls on the global distribution of contourite drifts: Insights from an eddy-resolving ocean model
Field | Value | Language |
dc.contributor.author | Tharn, Amanda C | |
dc.contributor.author | Dutkiewicz, Adriana | |
dc.contributor.author | Spence, Paul Spence | |
dc.contributor.author | Müller, Dietmar R. | |
dc.date.accessioned | 2020-01-31 | |
dc.date.available | 2020-01-31 | |
dc.date.issued | 2018-05-01 | |
dc.identifier.citation | Thran, A. C., Dutkiewicz, A., Spence, P., & Müller, R. D. (2018). Controls on the global distribution of contourite drifts: Insights from an eddy-resolving ocean model. Earth and Planetary Science Letters, 489, 228–240. https://doi.org/10.1016/j.epsl.2018.02.044 | en_AU |
dc.identifier.issn | 0012821X | |
dc.identifier.uri | https://hdl.handle.net/2123/21765 | |
dc.description | We thank the Flanders Marine Institute, Michele Rebesco, and Francisco Hernández-Molina for graciously permitting us to utilize and reproduce portions of their databases for this work. We are grateful to Lyndon Hall, who provided technical assistance in fine-tuning contourite coverage, and Kial Stewart, who conducted the eddy kinetic energy calculations used in our analysis. We also thank Simon Williams for technical assistance and fruitful discussions. This project was supported by the DBH Scholarship (Thran), the University of Sydney Faculty of Science Seed Grant (Dutkiewicz), and the Australian Research Council (ARC) ITRP grant IH130200012 (Müller). P. Spence was supported by an ARC DECRA Fellowship DE150100223 . Computing services were provided by the National Computational Infrastructure (NCI) in Canberra, Australia, which is supported by the Australian Commonwealth Government. We are grateful to Lara Pérez and Wilford Gardner for their careful reviews of our manuscript and their constructive comments. We also thank the editor, Martin Frank. | en_AU |
dc.description.abstract | Contourite drifts are anomalously high sediment accumulations that form due to reworking by bottom currents. Due to the lack of a comprehensive contourite database, the link between vigorous bottom water activity and drift occurrence has yet to be demonstrated on a global scale. Using an eddy-resolving ocean model and a new georeferenced database of 267 contourites, we show that the global distribution of modern contourite drifts strongly depends on the configuration of the world's most powerful bottom currents, many of which are associated with global meridional overturning circulation. Bathymetric obstacles frequently modify flow direction and intensity, imposing additional finer-scale control on drift occurrence. Mean bottom current speed over contourite-covered areas is only slightly higher (2.2 cm/s) than the rest of the global ocean (1.1 cm/s), falling below proposed thresholds deemed necessary to re-suspend and redistribute sediments (10–15 cm/s). However, currents fluctuate more frequently and intensely over areas with drifts, highlighting the role of intermittent, high-energy bottom current events in sediment erosion, transport, and subsequent drift accumulation. We identify eddies as a major driver of these bottom current fluctuations, and we find that simulated bottom eddy kinetic energy is over three times higher in contourite-covered areas in comparison to the rest o.f the ocean. Our work supports previous hypotheses which suggest that contourite deposition predominantly occurs due to repeated acute events as opposed to continuous reworking under average-intensity background flow conditions. This suggests that the contourite record should be interpreted in terms of a bottom current's susceptibility to experiencing periodic, high-speed current events. Our results also highlight the potential role of upper ocean dynamics in contourite sedimentation through its direct influence on deep eddy circulation. © 2018 Elsevier B.V. | en_AU |
dc.description.sponsorship | Australian Research Council-DE150100223,IH130200012 National Computational Infrastructure | en_AU |
dc.language.iso | en_AU | en_AU |
dc.publisher | Elsevier | en_AU |
dc.relation | Australian Research Council-DE150100223,IH130200012 | en_AU |
dc.rights | © 2018 Elsevier | en_AU |
dc.subject | bottom current | en_AU |
dc.subject | contourite | en_AU |
dc.subject | eddy | en_AU |
dc.subject | meridional overturning circulation | en_AU |
dc.subject | ocean modelling | en_AU |
dc.subject | sediment drift | en_AU |
dc.title | Controls on the global distribution of contourite drifts: Insights from an eddy-resolving ocean model | en_AU |
dc.type | Article | en_AU |
dc.subject.asrc | 040310 | en_AU |
dc.subject.asrc | 040503 | en_AU |
dc.identifier.doi | 10.1016/j.epsl.2018.02.044 | |
dc.type.pubtype | Post-print | en_AU |
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