Airborne geophysical investigation targets basal boundary conditions for the Institute and Moller ice streams, West Antarctica

Lead Research Organisation: University of Bristol
Department Name: Geographical Sciences

Abstract

The Institute and Möller ice streams (IIS/MIS) drain about 20% of the West Antarctic Ice Sheet (WAIS) to the Ronne Ice Shelf, yet our knowledge of their current form and flow history is severely restricted compared with other fast flowing regions in West Antarctica. Data relating to the ice thickness and the ice-sheet bed is limited to reconnaissance transects acquired in the 1970s. Bingham and Siegert (2007) inspected these data, and showed the remarkably smooth and flat bed was similar to the Siple Coast ice streams that drain to the Ross Ice Shelf. As the Siple Coast region is thought to be underlain by marine sediments, deposited when the ice sheet size was smaller than today, Bingham and Siegert (2007) concluded a similar, probably simultaneous, history for the Institute/Möller region. The implications of this finding are significant for future changes in West Antarctica. Bingham and Siegert's (2007) analysis allows us to hypothesise substantial former ice-shelf loss and grounding line retreat in two of the three major drainage outlets of West Antarctica. An extensive airborne geophysical survey of the Institute and Möller ice streams is therefore clearly warranted, to test this hypothesis and better understand the risk of future change. The survey will also allow a better depiction of bed topography and geological boundary conditions in West Antarctica, which will allow us to better quantify the flow and form of the entire WAIS through numerical modelling. The project's objectives are as follows. 1. To undertake an airborne geophysical survey of the Institute and Möller ice streams of West Antarctica. 2. To quantify bed topography and measure bed roughness from radar data. 3. To map englacial structures (layering and crevasses). 4. To determine power reflection coefficients, forming an appreciation of basal water distribution. 5. To analyse magnetic and gravity anomalies to derive geological boundary conditions for ice flow. 6. To employ numerical modeg to quantify modern and ancient ice flow processes. 7. To use numerical modelling to predict the risk of former changes reoccurring. This project will result in the following deliverables: 1. The quantification of subglacial topography (and bed roughness) in a hitherto poorly known region of West Antarctica. This information will be made available to the BEDMAP II database, and will make a fundamental contribution as an ice sheet modelling boundary condition. We will analyse these data to determine landscape evolution and ice sheet history. 2. The classification of subglacial thermal conditions and locations of subglacial lakes. This will allow us to comprehend how ice stream flow and subglacial lake/hydrology evolution is both interrelated and affected by subglacial geology and thermal conditions. 3. The measurement of the englacial structure in the WAIS. We will analyse this information to calculate the flow history of the ice sheet and to delineate the margins of the IIS and MIS both now and in the recent past. 4. The definition of crustal structure and subglacial geology of the IIS and MIS catchments of the WAIS. The glacial history of the WAIS is of direct relevance to assessments of the present day risk of collapse and sea level rise. We aim to report our results directly to the international scientific community by linking to the Scientific Committee on Antarctic Research's (SCAR) scientific research programme entitled Antarctic Climate Evolution (ACE), which integrates geology and geophy sical datasets, forming hypotheses concerning past changes, which can be tested through modelling. The ACE link also allows us to disseminate results to the IPCC through SCAR's observer status in that organisation. We will also make results available to the SCAR programme named Subglacial Antarctic Lake Environments (SALE) and will contribute the new magnetic dataset to the international Antarctic Digital Magnetic Anomaly Project.

Publications

10 25 50

Related Projects

Project Reference Relationship Related To Start End Award Value
NE/G013071/1 01/04/2010 31/07/2012 £662,419
NE/G013071/2 Transfer NE/G013071/1 01/08/2012 31/07/2014 £162,579
 
Description A airborne geophysical survey of the Institute and Moller ice stream was successfully collected.

The data revealed that a steep bed slope beneath the ice sheet margin exists, which could potentially lead to major ice sheet instability.

Independent ocean modelling confirmed the region to be at potential risk of change in future.

The data also reveal the underlying geology of the region.

Further, inspection of the data showed how water flows beneath the ice sheet.

Numerical modelling was used in conjunction with the geophysical data to show how the ice sheet will be sensitive in the next 100 years to change, and how the ice sheet has changed in the region since the last full glaciation.

We have also revealed major subglacial channels, formed by the action of subglacial water flow beneath a temperate ice sheet, possible 3 million years ago. Similar features have been found elsewhere in Antarctica, meaning the ice sheet dynamics may have been substantially different during the Pliocene.

We have also found a large (size of wales) plenation surface, which is likely to be a remnant of the preglacial landscape.
Exploitation Route The geophysical data are potentially important for understanding basal geology, for an understanding of resource implications.
Sectors Environment

 
Description Inaugural Lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Lots of questions from the public

Emails and twitter questions
Year(s) Of Engagement Activity 2015
URL https://search.yahoo.com/search;_ylt=AwrBT.E48QNWo04AaNhXNyoA;_ylc=X1MDMjc2NjY3OQRfcgMyBGZyA3lzZXRfY...
 
Description Pint of Science 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Many questions from the public about my talk

Emails, and social media contact, from the public about my talk
Year(s) Of Engagement Activity 2015
URL http://pintofscience.co.uk/event/undiscovered-origins/
 
Description Royal Society Meeting on Subglacial Lake Exploration 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation workshop facilitator
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact International dialogue on the future of Antarctic subglacial lake exploration.
Article in Eos on the findings of the workshop.
A white paper detailing the 20 year future for subglacial lake exploration, fed to the Antarctic Roadmap Challenge to integrate with other long-term plans for exploration.
A Royal Society book to document progress and plans.

A high degree of community shared knowledge.
A meeting with the Korean Antarctic Programme on subglacial exploration.
Year(s) Of Engagement Activity 2015
URL https://royalsociety.org/events/2015/03/subglacial-antarctic-lakes/