The underwater camera system begins its journey to the bottom of the drill string to keep the ship’s crew informed on what’s happening on the seafloor. Photo – Andrew Martin (IODP-JRSO)

An international team of scientists with several New Zealand participants has returned from a two-month voyage in the Kermadec Arc with the new knowledge about the inside workings of submarine volcanoes.

Using the scientific research ship JOIDES Resolution, they drilled a number of boreholes into the heart of the hydrothermally active Brothers submarine volcano.

The main aim of the USD 15 million expedition was to learn more about how metals are transported within submarine volcanoes and brought to the seafloor where they form metallic deposits.

Brothers submarine volcano is 400 km northeast of the Bay of Plenty coast and is about three times the size of White Island with its summit rising to within 1200m of sea level.

Voyage co-chief scientist, Cornel de Ronde of GNS Science, said: “We exceeded our expectations by some considerable margin and we have now compiled the most comprehensive information ever about the inner workings of a submarine arc volcano.

“We recovered about twice as much drill core from inside the volcano as the combined efforts of the two previous expeditions that tried to drill through the volcanic rock of submarine hydrothermal systems.”

The 225 meter of core recovered underwent preliminary analysis on the ship during the voyage and will now be shared among participating countries for more detailed study.

The initial findings from the voyage are preliminary only and it will take extensive onshore analysis and interpretation of all the data to fully realise the knowledge gains from the expedition.

Voyage co-chief scientist Susan Humphris, of US-based Woods Hole Oceanographic Institution, added: “Chemical reactions between rocks and seawater at depth in the volcano change the chemistry of the fluid that is released into the ocean through hydrothermal vents.

The expedition to the Kermadec Arc was funded by the consortium of 23 countries that make up IODP, with the single largest contributor being the National Science Foundation in the United States.





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