Ice sheet change in the Amundsen Sea Embayment

This NERC-funded project will produce a unique high-resolution record of ice sheet thinning over the past 20,000 years from the poorly-known western Amundsen Sea Embayment of Antarctica. Detailed ice sheet histories such as this are urgently needed for testing and improving models that are used to forecast the magnitude and timing of future sea level rise.

The West Antarctic Ice Sheet (WAIS), and particularly its Amundsen Sea sector, is critical for predicting sea level change. The water locked inside it is enough to add up to 1.2 metres to global sea level. Since WAIS is already retreating, there is the potentially for sea level to rise very quickly in the coming few centuries, resulting in widespread damage to low-lying cities around the world.

Map of the Amundsen Sea Embayment showing the ANiSEED study area (dotted box).

We will use exciting innovations in the technique of surface exposure dating on rock samples to determine small fluctuations in ice sheet thickness with greater precision than has previously been achieved in Antarctica. This approach will enable us to provide exceptionally-detailed records of past ice sheet change over centuries to millennia.

An important strand of the project is the collaboration with modellers who use geological data to test and tune their ice sheet models. Our new data will permit significant improvements in their model outputs, ultimately contributing to more accurate prediction of future global sea level rise.

To understand why glaciers in the western Amundsen Sea Embayment are important, watch this video by Eric Rignot (Jet Propulsion Laboratory, NASA):

Principal Investigator Jo Johnson is a geochemist specialising in Quaternary dating techniques. She has worked on reconstructing ice sheet history and palaeoenvironments at BAS since 2002, and as a Marie Tharp Fellow at Lamont-Doherty Earth Observatory in 2011. As well as managing the project and interpreting results, she will be undertaking a field season in November 2015 to collect rock samples for reconstructing ice sheet history from the western Amundsen Sea Embayment of Antarctica.

Co-Investigator Steve Roberts’ expertise is in the fields of Quaternary geomorphology and limnology. He also has extensive Antarctic fieldwork experience, and will be accompanying Jo to the western Amundsen Sea Embayment for fieldwork in 2015/16. He will be producing detailed geomorphological maps of the field areas using high-resolution satellite imagery and field observations.

View of one of our field sites: Turtle Rock in the western Amundsen Sea Embayment, Antarctica. In the foreground are scientists and helicopters from the German research vessel RV Polarstern, which visited the area in 2006.

We aim

• To deliver a high-resolution record of past ice sheet change in a critical but poorly understood region of Antarctica, the western Amundsen Sea Embayment, in order to improve our ability to predict sea level rise.

We will publish this record in a format suitable for use in both ice sheet and Glacial Isostatic Adjustment models.

• To employ innovations in the technique of ¹⁰Be exposure dating of rock surfaces, enabling centennial-millennial fluctuations in the rate of ice sheet thinning to be determined with greater precision than before.

• To establish world-leading expertise in high-precision cosmogenic ¹⁰Be exposure dating in the UK.

This will be achieved through transfer of knowledge from Lamont-Doherty Earth Observatory to Imperial College London and the Scottish Universities Environmental Research Centre (SUERC).

It will have great benefit to the UK science community, affording new avenues for cutting-edge research in environmental science.

 Collaborative partners

Dylan Rood (Imperial College, London, UK)

Co-Investigator

Dylan is responsible for preparing and analysing the rock samples for ¹⁰Be surface exposure dating. He will be working closely with Joerg Schaefer to transfer expertise in high-precision dating techniques to technical staff at Imperial and Scottish Universities Environmental Research Centre (SUERC). Dylan is also an expert in using Accelerator Mass Spectrometry to measure ¹⁰Be in rocks, and will be doing this as part of the project.

Joerg Schaefer (Lamont-Doherty Earth Observatory, Columbia University, USA)

Project Partner

Joerg is a world expert in cosmogenic dating, specialising in high precision ¹⁰Be dating in glacial environments. Jo and Joerg have an established collaboration through Jo’s visit to Lamont-Doherty Earth Observatory as a Marie Tharp Fellow in 2011. As a Project Partner on the grant, Joerg will play a critical role in overseeing sample preparation for both ¹⁰Be and in situ ¹⁴C dating and transferring his knowledge to Imperial and SUERC through close collaboration with Dylan.

Pippa Whitehouse (Durham University, UK)

Project Partner

Pippa specialises in using numerical ice sheet models to create glaciologically- and data-consistent reconstructions of ice mass changes throughout Antarctica since the Last Glacial Maximum. Her studies of the response of the earth to changes in ice and ocean loading during glacial cycles –otherwise known as Glacial Isostatic Adjustment (GIA) – are helping to improve our understanding of sea level, deformation of the solid earth and estimations of the volume of global ice sheets, both now and in the past. As a Project Partner, Pippa will be advising us on how to produce data that is useful for GIA modellers and will be using our new data to better constrain her own model.

David Pollard (Penn State University, USA)

Project Partner

David is an expert in numerical modelling of the Earth’s climate, including ice sheets. He has been worked on modelling past retreat and regrowth of the West Antarctic Ice Sheet, and more recently has started focusing on modelling the last deglacial retreat in the Amundsen Sea Embayment. As a Project Partner, he will be helping us to make our new data more readily usable to researchers outside the field of Quaternary dating and will be comparing our high-resolution chronology from the western Amundsen Sea Embayment with his 3D ice sheet model simulation.

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8. ANTARCTIC BLOG: Extreme Geology #4

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