Studying the Balleny mantle plume

Understanding the role of the Balleny Mantle Plume in the Tasmania-Antarctica breakup.
Voyage No

IN2018_V08

27 Dec, 2018

to

10 Jan, 2019

Hobart

to

Hobart

Chief Scientist

A/Prof Joanne Whittaker

Institution

University of Tasmania

Voyage summary

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.

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Voyage impact

As a result of this voyage, researchers now have a better understanding of the formation and evolution through time of the seamounts of the Tasmanian Seamount Chain. During the voyage, 34 previously unmapped seamounts in the southern Tasman Sea were mapped, which will be used to help understand tectonic setting, eruptive style, palaeo-water-depth and sedimentation patterns.

Rock samples were collected from 14 seamounts, with these rocks being described macroscopically, petrographically and mineralogically to classify the type of volcanism on the seamounts. 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.