Team to investigate icebergs breaking off Antarctica ice shelf

The floating Brunt Ice Shelf, home to the BAS Halley Research Station, has recently witnessed two significant calving events, including the spectacular A-81 iceberg, the size of Greater London, earlier this year. Calving is when chunks of ice break off at the terminus, or end, of a glacier.

The team will collect shallow ice cores as well as deploying seismic instruments, radar and GPS receivers to delve into the evolution of cracks on the ice shelf.

Ice samples will be taken for testing at the Rock and Ice Physics Laboratory at UCL Earth Sciences as well as the University of Cambridge. These tests will help the scientists to observe variations in the physical properties of the ice, including grain size, impurity content, seismic properties and fracture toughness. The collected data will contribute to a better understanding of the factors influencing crack growth and calving.

Team member Professor Tom Mitchell (UCL Earth Sciences) said: “We are very excited to get our hands on these ice drill core samples, which will be transported to our rock and ice physics labs at UCL. Our ice lab experiments will provide fundamental information to allow us to further understand how ice fractures initiate, propagate, and lead to large-scale calving events that could become more frequent as the continent is affected by environmental change.”

Dr Liz Thomas, an ice coring expert at BAS and one of the lead scientists on the mission, said: "The Brunt Ice Shelf is one of the most studied ice shelves in the world, with active rifts that are relatively easily accessible. It therefore provides an ideal test bed to study the processes that take place just before a major calving event."

The Brunt Ice Shelf has a rich history of strain monitoring, and recent years has seen the development of several huge cracks, including Chasm-1 and the Halloween Crack. Notably, two large icebergs, A-74 and A-81, have calved in the last three years, providing a unique dataset on the timing of calving.

Dr Oliver Marsh, a glaciologist at BAS and principal investigator on the project, said: “Large calving events can dramatically alter the shape of ice shelves, modifying ocean circulation and affecting ice dynamics through increased ice flow into the ocean.  The physics behind fracture in ice is not well represented in models making it difficult to predict how calving rates will change in the future.”

The mission is part of the RIFT-TIP project, which aims to provide insights into the mechanics of iceberg calving and fracture growth in ice shelves, contributing to our understanding of the impacts of climate change on Antarctica and its implications for global sea levels.

Links

• RIFT-TIP project
• Professor Tom Mitchell’s academic profile
• UCL Earth Sciences
• UCL Mathematical & Physical Sciences

Source

• British Antarctic Survey

Image

• Brunt Ice Shelf. Credit: British Antarctic Survey

Media contact

Mark Greaves

m.greaves [at] ucl.ac.uk