KNOW THE DRILL

Scientific ocean drilling has made major discoveries that allow us to understand how Earth works, how it has changed, and what its future holds. Southampton researcher Dr Rosalind Coggon has her sights set on ocean drilling’s future potential.

Ocean drilling has provided proof for plate tectonics, made it possible to reconstruct past climates, and – by drilling into the crater created by the meteorite that wiped out dinosaurs – understand cataclysmic environmental changes.

Scientific ocean drilling is a huge international collaboration that has been running for more than 50 years, using drilling ships and platforms to recover samples of sediments, rocks, and fluids from beneath the seafloor.

Dr Rosalind (Roz) Coggon, a Royal Society University Research Fellow in the University’s School of Ocean and Earth Science, has worked within ocean drilling for more than 20 years. She explained: “Scientific ocean drilling operates in some of the Earth’s most challenging environments to secure a wide range of otherwise inaccessible samples and observations that are critical to understanding our planet.”

Ocean sediments record tens of millions of years of changing climate, environmental conditions, and evolution, giving us a rare insight into our planet’s past. The underlying rocks that form the ocean basins reveal how Earth’s great tectonic plates are formed and how they generate natural hazards such as earthquakes and tsunamis.

In the past, scientific drilling has been guided by 10-year plans (such as the 20132023 Illuminating Earth). In 2020, however, scientists involved in ocean drilling developed a new 30-year framework, Exploring Earth by Scientific Ocean Drilling. Roz was Colead Editor of the 2050 framework, working alongside Professor Anthony Koppers from Oregon State University.

“It’s an ambitious blueprint for the next 30 years of scientific ocean drilling,” said Roz. “It provides a wide vision of the exciting science that should be pursued over the coming decades. We have only ever worked in 10-year increments before, so looking ahead 30 years allows greater potential.

“The development of new technologies, and our science, over that timeframe presents lots of really exciting opportunities to provide the data we need to address a range of natural and human-caused environmental challenges facing society.”

Roz won two awards for her work on the framework: the sixth ECORD (European Consortium for Ocean Research Drilling) Award in October 2020, and the 2021 Asahiko Taira International Scientific Ocean Drilling Research Prize.

Researching past ocean chemistry

Roz’s current research involved two International Ocean Discovery Program (IODP) drilling expeditions in 2022 as part of a project to investigate how the Earth’s crust ages as it spreads away from the mid-Atlantic Ridge – supporting scientists’ understanding of long-term global chemical cycles, such as the carbon cycle.

The South Atlantic Transect expeditions (IODP Expeditions 390 and 393) – for which Roz and Damon Teagle, Professor of Geochemistry at Southampton, were Co-Chief Scientists aboard the JOIDES Resolution drilling vessel – involved drilling at seven sites with crustal ages ranging from seven million to 61 million years.

Roz explained: “The strategy was to drill a series of sites from the mid-Atlantic Ridge towards South America on crust of different ages. We were revisiting an area that was originally drilled in 1968 on an expedition that provided proof for plate tectonics. We went back to the same area and collected sediment sections, and also drilled up to 350 metres into the lavas that form the underlying ocean crust.

“It was exhilarating to follow the path of the scientific ocean drilling pioneers who explored the South Atlantic over 50 years ago to prove that seafloor spreading along the mid-ocean ridges produces new oceanic crust. That crust forms the basins that hold the oceans – but it is not simply an inert container for seawater.

“Our strategy of drilling crust of increasing age was designed to investigate how seawater and the rocks that hold it interact – both contributing to and recording changes in the long-term evolution of our planet and allowing unique ecosystems to thrive deep beneath the seafloor.”

Find out more about Exploring Earth by Scientific Ocean Drilling iodp.org/2050-science-framework