Abstract
The sedimentary record, and associated micropalaeontological proxies, is one tool that has been employed to quantify a region’s tropical cyclone history. Doing so has largely relied on the identification of allochthonous deposits (sediments and microfossils), sourced from deeper water and entrained by tropical cyclone waves and currents, in a shallow-water or terrestrial setting. In this study, we examine microfossil assemblages before and after a known tropical cyclone event (Cyclone Hamish) with the aim to better resolve the characteristics of this known signal. Our results identify no allochthonous material associated with Cyclone Hamish. Instead, using a swathe of statistical tools typical of ecological studies but rarely employed in the geosciences, we identify new, previously unidentified, signal types. These signals include a homogenising effect, with the level of differentiation between sample sites greatly reduced immediately following Cyclone Hamish, and discernible shifts in assemblage diversity. In the subsequent years following Hamish, the surface assemblage returns to its pre-cyclone form, but results imply that it is unlikely the community ever reaches steady state.
Highlights
Temperate siliciclastic settings[12,13,14,15,17,18]
Our results do not identify any evidence that Cyclone Hamish created an allochthonous foraminifera assemblage consistent with that identified for other similar events
We are able to highlight a range of signals that we can directly attribute to our known tropical cyclone event by employing a suite of techniques typical of ecological studies but rarely employed to address questions in the geosciences
Summary
Temperate siliciclastic settings[12,13,14,15,17,18]. Fewer studies have used foraminifera to quantify regional hazard histories in tropical carbonate settings[29,30]. Our event is Cyclone Hamish (2009), a Category 5 tropical cyclone at its maximum intensity, but a Category 4 tropical cyclone when it reached Heron Reef (Fig. 1). As we had previously collected foraminifera samples from Heron Reef in 2008, prior to the impact of Cyclone Hamish, this afforded a rare opportunity to characterise a disturbance assemblage generated by a known tropical cyclone and contrast it with a commensurate ‘pre-event’ assemblage. Our results do not identify any evidence that Cyclone Hamish created an allochthonous foraminifera assemblage consistent with that identified for other similar events. This means that Cyclone Hamish would not be detected in the sedimentary record of Heron Reef using traditional approaches. We conclude by considering the implications of our result for future assessments of tropical cyclone histories using the sedimentary record
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
