- Title
- Sedimentology, structure and age estimate of five continental slope submarine landslides, eastern Australia
- Creator
- Clarke, S.; Hubble, T.; Webster, J.; Airey, D.; De Carli, E.; Ferraz, C.; Reimer, P.; Boyd, R.; Keene, J.
- Relation
- ARC
- Relation
- Australian Journal of Earth Sciences Vol. 63, Issue 5, p. 631-652
- Publisher Link
- http://dx.doi.org/10.1080/08120099.2016.1225600
- Publisher
- Taylor & Francis
- Resource Type
- journal article
- Date
- 2016
- Description
- Sedimentological and accelerator mass spectrometry (AMS) 14C data provide estimates of the structure and age of five submarine landslides (∼0.4–3 km3) present on eastern Australia's continental slope between Noosa Heads and Yamba. Dating of the post-slide conformably deposited sediment indicates sediment accumulation rates between 0.017 m ka–1 and 0.2 m ka–1, which is consistent with previous estimates reported for this area. Boundary surfaces were identified in five continental slope cores at depths of 0.8 to 2.2 m below the present-day seafloor. Boundary surfaces present as a sharp colour-change across the surface, discernible but small increases in sediment stiffness, a slight increase in sediment bulk density of 0.1 g cm–3, and distinct gaps in AMS 14C ages of at least 25 ka. Boundary surfaces are interpreted to represent a slide plane detachment surface but are not necessarily the only ones or even the major ones. Sub-bottom profiler records indicate that: (1) the youngest identifiable sediment reflectors upslope from three submarine landslides terminate on and are truncated by slide rupture surfaces; (2) there is no obvious evidence for a post-slide sediment layer draped over, or burying, slide ruptures or exposed slide detachment surfaces; and (3) the boundary surfaces identified within the cores are unlikely to be near-surface slide surfaces within an overall larger en masse dislocation. These findings suggest that these submarine landslides are geologically recent (<25 ka), and that the boundary surfaces are either: (a) an erosional features that developed after the landslide, in which case the boundary surface age provides a minimum age for the landslide; or (b) detachment surfaces from which slabs of near-surface sediment were removed during landsliding, in which case the age of the sediment above the boundary surface indicates the approximate age of landsliding. While an earthquake-triggering mechanism is favoured for the initiation of submarine landslides on the eastern Australian margin, further evidence is required to confirm this interpretation.
- Subject
- mass-failure; multibeam; seafloor geomorphology; continental margin; southeast Australia; continental slope; passive margin; sedimentation rates; submarine landslide
- Identifier
- http://hdl.handle.net/1959.13/1345160
- Identifier
- uon:29576
- Identifier
- ISSN:0812-0099
- Rights
- This is an Accepted Manuscript of an article published by Taylor & Francis in Australian Journal of Earth Sciences on 20/09/2016, available online: http://www.tandfonline.com/10.1080/08120099.2016.1225600
- Language
- eng
- Full Text
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