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Project details
| Title: | Evolution of the Seafloor of the Australian-Antarctic Southern Ocean |
| Id: | 2626 |
| Investigator(s): | Phil Vandenbossche
CSIRO National Collections and Marine Infrastructure [details] |
| Description: | The seafloor in the Southern Ocean records a 100+ million-year history of plate tectonic motions between Australia and Antarctica. Most of what we know about these plate tectonic motions and the formation of the seafloor, comes from satellite gravity data and ship-track magnetic data. However, in the past decade, progressively more multibeam (‘swath’) bathymetry data has been collected across vast swathes of the Australian Southern Ocean, particularly offshore southwestern Tasmania (in the SOTS – Southern Ocean Time Series region) and to the southwest of Perth (from the search for missing Malaysia Airliner, MH370). These datasets provide detailed high-resolution information of the seafloor morphology across two areas of a similar age on the Australian plate but formed at opposite ends of the tectonic spreading system. This presents a unique opportunity to study and compare the seafloor at these locations, which will yield valuable new information as to how the seafloor has accreted and been influenced by processes such as plate tectonic motions, settings and reorganisations, mantle plumes, long-wavelength mantle flow as well as mantle geochemistry and temperature. This project therefore aims to provide new research insights into the evolution of the seafloor of the Australian-Antarctic Southern Ocean and East Gondwana region. There are two primary objectives that will augment existing data in support of this research: 1. Acquire towed magnetometer data between the Tasman Fracture Zone and SOTS site (in an NNE-SSW orientation), as part of the transit to/from SOTS. No physical rock dating is known to exist in the study area and therefore magnetic data will provide valuable indicative ages of the seafloor crust across the region. 2. Acquire multibeam bathymetry data in areas previously unmapped. Areas to target lie to the west and south of the SOTS site. This will extend the seafloor mapping coverage in the region, thereby providing valuable new bathymetry data that will be used to analyse the seafloor morphology and tectonic fabric (and contribute to the International Seabed 2030 project). |
| Years: | 2023 |
List of surveys that this project was on. Click on column header to sort.
Use [details] link to view survey details (map, reports, metadata etc) including links to download data.
| Survey | Investigator | Description |
|---|---|---|
| IN2024_V02 [details] |
Shadwick (CSIRO O&A) | The primary objective is to first deploy a new set of SOTS moorings (SOFS-13 and SAZ-26) and then recover the existing SOTS moorings (SOFS-12, SOFS-11-SWAP and SAZ-25). Each of the SOTS moorings delivers to specific aspects of the atmosphere-ocean exchanges: • the SAZ sediment trap mooring collects samples to quantify the transfer of carbon and other nutrients to the ocean interior by sinking particles and investigate their ecological controls. • the Southern Ocean Flux Station (SOFS) mooring measures meteorological and ocean properties important to air-sea exchanges, ocean stratification, waves, currents and biological productivity and ecosystem structure. Water samples are collected for more detailed nutrient and plankton investigations after recovery. Ancillary work will obtain supporting information on atmospheric and oceanographic conditions using CTD casts, underway measurements, Continuous Plankton Recorder, and autonomous profiling Biogeochemical-Argo floats, and potentially casts of a bio-optical sensor package. |
| IN2023_V03 [details] |
Elizabeth Shadwick (CSIRO O&A) | The primary objective is to first deploy a new set of SOTS moorings (SOFS-12 and SAZ-25) and then recover the existing SOTS moorings (SOFS-11 and SAZ-24). Each of the SOTS moorings delivers to specific aspects of the atmosphere-ocean exchanges: • the SAZ sediment trap mooring collects samples to quantify the transfer of carbon and other nutrients to the ocean interior by sinking particles and investigate their ecological controls. • the Southern Ocean Flux Station (SOFS) mooring measures meteorological and ocean properties important to air-sea exchanges, ocean stratification, waves, currents and biological productivity and ecosystem structure. Water samples are collected for more detailed nutrient and plankton investigations after recovery. Ancillary work will obtain supporting information on atmospheric and oceanographic conditions using CTD casts, underway measurements, Continuous Plankton Recorder and autonomous glider, and potentially casts of a bio-optical sensor package. Voyage objectives: 1. Deploy SOFS-12 meteorology/biogeochemistry mooring. 2. Deploy SAZ-25 sediment trap mooring. 3. Recover SOFS-11 meteorology/biogeochemistry mooring. 4. Recover SAZ-24 sediment trap mooring. 5. CTD sampling (2 cast to 4550m, 2 to 600m) at the SOTS site, including collecting samples for nutrients, oxygen, dissolved inorganic carbon, alkalinity, and particulate matter analyses. 6. Ship meteorological observations at SOFS buoy for comparisons. 7. Deployment of CSIRO glider for satellite calibration validation during the SWOT fast sampling phase, in support of IN2023_V07. 8. Potential recovery of BGC-Argo float, or CSIRO glider, using new recovery device. 9. Tow CPR on transit to SOTS (after the seamount survey). 10. Carry out underway air and water sampling and sensor measurements, including bio-optics and bio-acoustics. |