Floating lab drills for climate clues

A floating laboratory that has just finished probing New Zealand’s largest earthquake fault is sailing to Antarctica to drill kilometres deep into ice sheets for climate change clues.

International scientific research ship JOIDES Resolution is in New Zealand waters undertaking expeditions over 18 months to study quakes, tectonics, undersea volcanoes and climate change.

It’s part of a five-year project, a collaboration of the 26-nation International Ocean Discovery Programme, to explore the newly discovered “lost” continent of Zealandia.

The 140m state-of-the-art drill ship has called in to Lyttelton Port having completed a major programme looking at the Hikurangi subduction zone, off Gisborne. Understanding how the massive “locked zone” on the fault works is hugely important for New Zealand and the rest of the world, scientists say.

Niwa marine geologist Phil Barnes said the expedition to look at slow slip events at subduction zones was the first of its kind in the world.

The Gisborne zones are relatively shallow and allow scientists to drill 600m to 750m below the seafloor to help them understand what kind of rocks are associated with slow-slipping faults.

It has also helped them work out why some faults are prone to slow slips while others aren’t and what sort of quake and tsunami hazards they pose for New Zealand’s east coast communities and elsewhere.

JOIDES Resolution will leave Lyttelton in the next few days for a mission to the Ross Sea so scientists can try to understand what things were like there about 20 million years ago.

A previous expedition found evidence from core samples that Antarctica was tropical in parts about 50 million years ago. The samples revealed fossilised remains of palm trees and showed tropical water temperatures of 25C to 28C.

The New Zealand leader of the Ross Sea expedition, Rob McKay of Victoria University, says paleo-calibrated models indicate Antarctica has the potential to contribute more than 1m of sea-level rise by the year 2100 and more than 15m by 2500 if emissions continue unabated.

He hopes the two-month trip, which will involve six geological drill cores, will improve understanding of the link between warming oceans and melting ice sheets.