A/Prof Joanne Whittaker
University of Tasmania
Research voyage to the Southern Ocean and Tasman Sea to study the role of the Balleny mantle plume in the plate tectonic break up between Australia and Antarctica.
For the past few million years, the Balleny plume has resided beneath the Antarctic tectonic plate, forming the Balleny seamount chain located offshore Cape Adare, Antarctica. The role that mantle plumes - hot upwellings from the Earth’s interior - play in driving continental breakup and plate tectonic motions remains a key question in the Earth Sciences. The Balleny plume has been implicated in causing/aiding the continental breakup between Tasmania and Cape Adare 30-50 million years ago.
Seafloor mapping data and dredged samples collected during this voyage will be used to test the hypothesis that the Balleny Plume played a significant role in the plate tectonic breakup between Tasmania and Cape Adare, Antarctica. Researchers will also investigate the plume’s influence on the bathymetric evolution of the Tasman Gateway and related onset of the Antarctic Circumpolar Current.
During the voyage, 34 previously unmapped seamounts in the southern Tasman Sea were mapped. These data will be used to help understand tectonic setting, eruptive style, paleo-water-depth and sedimentation patterns in the region. Rock samples were collected from 14 seamounts and these samples have been described macroscopically, petrographically and mineralogically to classify the type of volcanism on the seamounts.
As a result of this voyage, researchers now have a better understanding of the formation and history of the seamounts of the Tasmanian Seamount Chain. Further geochronology and geochemistry study will seek to further understand the timing of seamount formation, formation mechanism and timing of subsequent erosion and/or sedimentation.
Seamounts are important habitats for open-ocean ecosystems. This research aligns with the National Marine Science Plan 'Challenge 4 - biodiversity, conservation and ecosystem health' and supports the identification of areas of important conservation value.
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