An IMAS-led research team on the CSIRO research vessel Investigator sailed from Perth on 10 January for a two-month voyage that could lead to Australia’s marine jurisdiction near Heard Island being extended by an area the size of Switzerland.
The main focus of the voyage is to study the ancient rifting, break-up, and separation of tectonic plates that split a giant, once-contiguous oceanic plateau into two major Indian Ocean seafloor features, Broken Ridge and the Kerguelen Plateau, to the west and southwest of Perth.
The science team includes researchers from 13 institutions and 11 nations, including Australia, Canada, China, Denmark, Germany, Italy, Poland, Singapore, Turkey, UK, and USA.
The scientists will also acquire, analyse, and interpret samples from William’s Ridge, a seafloor feature that extends southeast from the Kerguelen Plateau, to establish whether the area qualifies under international law to be included in Australia’s marine jurisdiction.
If judged eligible by the United Nations Commission on the Limits of the Continental Shelf (CLCS), it could add 40,000 square kilometres to the continental shelf recognised as part of Australia’s jurisdiction.
The voyage’s Chief Scientist, IMAS Professor Mike Coffin, said the seafloor of the Indian Ocean has undergone a complex evolution since it began forming more than 150 million years ago, and the geological events involved are an enigma.
“Like other oceans, the Indian Ocean has formed by seafloor spreading among tectonic plates,” Professor Coffin said.
“However, to the west and southwest of Perth this seafloor spreading interacted with hotspot volcanism, where magma rising from deep within the Earth has created oceanic crust much thicker than normal as the plates have broken up.
“During the voyage researchers from Australia, China, Denmark, Germany, Italy, Russia, and USA will carry out a wide range of imaging and sampling techniques to acquire data and samples using the Investigator’s cutting-edge technology.
(Image, above, RV Investigator crew with a towed camera in the Southern Ocean, January 2016. Credit: Pete Harmsen)
“An exceptional multidisciplinary team of international scientists will subsequently analyse the data and samples to improve our understanding of parts of the seafloor that have never been studied in this level of detail.”
Professor Coffin said consideration of the possible extension of Australia’s marine jurisdiction around William’s Ridge has been on hold due to a lack of sufficient data and samples from the continental shelf.
“The data and samples we collect will inform a possible future submission to the CLCS to extend Australia’s marine jurisdiction to include the continental shelf on and around William’s Ridge, an extension of the Central Kerguelen Plateau near Australia’s Heard Island.
“The CLCS assessed Australia’s continental shelf entitlements from 2004 to 2008, but in 2008 consideration of this area was postponed at Australia’s request due to the shortage of relevant geological samples and geophysical data.
“Whether William’s Ridge is eligible to be continental shelf is unknown, as are the geological processes that led to its development.
“Our voyage will for the first time carry out detailed investigations of the ridge, including multibeam bathymetry, seismic imaging, sub-bottom-profiling, dredging of rock samples, and deep towed-camera footage.
“This comprehensive and unique data and sampling will help the CLCS to decide whether Australia’s marine jurisdiction should be extended by an area the size of Switzerland,” Professor Coffin said.
The voyage will include scientists and students from Geoscience Australia, Macquarie University, University of Queensland, Australian National University, GFZ German Research Centre for Geosciences, James Cook University, University of Western Australia, College of the Atlantic, and Institute of Oceanology, Chinese Academy of Sciences.
The project also involves shore-based researchers from the Alfred Wegener Institute for Polar and Marine Research, University of Cambridge, Oregon State University, Natural History Museum of Denmark, and GEOMAR Helmholtz Centre for Ocean Research Kiel.
Investigator is Australia’s only research vessel dedicated to blue-water research and is owned and operated by CSIRO – Australia’s national science agency. The vessel conducts research year-round and is made available to Australian researchers and their international collaborators.
The voyage is scheduled to return on Friday 6 March.
The Roaring Forties are in our wake - we’ve crossed the Southeast Indian Ridge and the Antarctic Convergence - and for the next several weeks we’ll be working in the Southern Ocean’s Furious Fifties. The long transit from Henderson, Western Australia, to the start of the first phase of our investigations on the Kerguelen Plateau concluded on 18 January. Into the second week of transit, we continued to test equipment and gain experience with shipboard systems and procedures. As on all transits, we’re continuously acquiring multibeam sonar, backscatter, sub-bottom profiler, gravity, and magnetics data. And we continue to launch robotic floats, three this week, for the international Argo program.
The day we sailed from Henderson we commenced a daily floating seminar program straddling the change in science watches at 1400; most members of the science party are standing 0200-1400 or 1400-0200 watches. At the seminars, typically two or three people speak for 15-20 minutes each, including questions and answers. The seminars provide an opportunity for us to introduce ourselves, our expertise, and our research plans for the voyage to one another. This is particularly important because this voyage is the first time the multidisciplinary team has been co-located, and many people haven’t met each other previously. Everyone on the ship is welcome both to attend and to give seminars.
A critical new system for our study is multichannel seismic reflection, which images sub-seafloor structure and stratigraphy. Australia’s Marine National Facility has recently acquired its own complete system, which has been funded by Geoscience Australia. This is a small-scale, high-resolution system used for research purposes. The seismic source and receiver are towed behind RV Investigator, the latter with an active length of 500 m. The data are monitored, quality-controlled, recorded, and initially processed in the ship’s Operations Room.
(Image, right: the seismic receiver (hydrophone streamer) on the large winch (right) with members of the IN2020_V01 science party. Credit: David Dieckfoss)
We conducted the first test of the complete system on 14 January en route south, and anticipate deploying it operationally in our William’s Ridge study area following seafloor mapping. Acquisition and operational deployment of the multichannel seismic reflection system represent a major milestone in capability for Australia’s marine geoscience community, which until this voyage has lacked such a national capability. The fundamental geophysical data gathered by this system will directly contribute to a potential new or revised Australian submission to the United Nations Commission on the Limits of the Continental Shelf (CLCS) for an increase in Australia’s marine jurisdiction around Heard and McDonald Islands.
(Image, below: The seismic source (air impulsive) in its storage box on the aft deck. Credit: Mike Coffin)
Phase one of our three-phase research program is an estimated 2-day seafloor mapping and dredging campaign on Rig Seismic Seamount, situated in the Labuan Basin to the east of the Central Kerguelen Plateau. As of the evening of 19 January, we have completed mapping the feature and have just recovered our first of three planned dredges. Rig Seismic Seamount, rising from ~4500 m to ~2700 m, takes its name from Geoscience Australia’s former (1984-1998) research vessel Rig Seismic, aboard which scientists (including myself on my first expedition to the region) discovered the seamount in 1985 (RS47). On that voyage we acquired the first multichannel seismic reflection data from the Australian sector of the Kerguelen Plateau. In 1997, in preparation for Australia’s 2004 submission to the UN CLCS, Rig Seismic made two further voyages to this region, RS179 and RS180, on which I and IN2020_V01 Co-Chief Scientist George Bernardel, respectively, sailed.
Long summer days are conducive to our work program, morale, and aesthetics. Nights are only about 7.75 hours long. May the 19 January sunshine and gentle-to-moderate wind and wave conditions augur well for the upcoming several weeks of work in the Furious Fifties.
RV Investigator voyage IN2020_V01 – Development of William’s Ridge, Kerguelen Plateau: tectonics, hotspot magmatism, microcontinents, and Australia’s Extended Continental Shelf – departed Henderson, Western Australia, on Friday 10 January, bound for the Heard Island region, southern Indian Ocean, on a 57-day mission. The overarching objectives of the voyage are to:
In addition, we will undertake a supplementary project to determine the timing of the most recent collapse of the West Antarctic Ice Sheet.
(Image, right: University of Tasmania undergraduate student Sylvie King and the SOCCOM float Mud Skipper that she adorned. Credit: David Dieckfoss)
I first had the idea for the primary investigation in 2015, and in the intervening five years, my colleagues and I have assembled a multi-disciplinary, international team of researchers and students, submitted multiple applications to various agencies and authorities for support and permissions, been granted shiptime and science funding, and obtained requisite environmental permits. Thus the voyage is the culmination of considerable effort and planning involving scores of people from around the world.
The entire shipboard science and science support team first assembled 6-10 January for mobilisation of the voyage at BAE Henderson Port, Western Australia, where RV Investigator was berthed. Mobilisation activities were nonstop and intense for four days, mirroring the enthusiasm and anticipation of all voyage participants.
(Image, left,: SOCCOM float being deployed by RV Investigator crew members. Credit: David Dieckfoss)
We number 56 souls on this voyage. That total includes 23 members of the science party, 11 science support staff, two medical specialists, and 20 ship’s crew. The 34-strong research team is a veritable United Nations, with 11 nationalities from four continents represented. This diversity reflects our efforts to assemble the best scientific team globally to achieve our research objectives as well as the boundless nature of the global ocean.
We embarked from Henderson at 0830 Friday 10 January and commenced the long transit to the Heard Island region. During the first three days of the transit, we’ve been acquiring multibeam, backscatter, sub-bottom profiler, water-column acoustic, magnetics, and gravity data continuously. We have also launched one robotic float, Mud Skipper (adopted and named by students from the College of Coastal Georgia, USA), for the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project (see photos). The sea state has been benevolent, facilitating development of our sea legs. We anticipate arriving at our first intensive study area, William’s Ridge, on 19 or 20 January, depending on weather conditions and equipment testing.