Updated August 2016
Sarah Greenwood

My interests are in palaeo-glaciology and glacial geomorphology: investigating how an ice sheet behaves from the landform signatures it has left behind. The sediments mobilised and landforms moulded by the flow of an ice sheet allow us to read the history of the ice flow regimes responsible, and their interactions with past climates and oceans. In recent years, exceptionally high resolution digital terrain models of land and the seafloor have revolutionised the way that we can study glaciated landscapes. I work at a regional-to-continental scale in both terrestrial and marine environments, using a variety of topographic and seafloor geophysical datasets, to analyse glacial landforms and landscapes and determine the dynamics, stability of and controls upon past ice flow and retreat.

Deglaciation dynamics of the Fennoscandian Ice Sheet
I am working on several projects related to retreat dynamics of the Fennoscandian Ice Sheet, in particular in exploiting new, high resolution datasets from present-day submerged terrain. Marine-based sectors of ice sheets are generally considered to behave in a more dynamic, potentially unstable fashion than their terrestrially-grounded counterparts, but most of our understanding of Fennoscandian Ice Sheet decay stems from terrestrial geological archives.

In the Gulf of Bothnia, a rich and immaculately preserved glacial landform record reveals the flow and collapse of ice in this shallow marine basin. With colleagues at SU and the Geological Survey of Sweden, we are combining geomorphological research with numerical ice flow modelling to investigate palaeo-flow dynamics through the Gulf, and to determine the importance of atmospheric warming, surface melting and iceberg calving in driving ice margin retreat. 

In Lake Vättern in south-central Sweden, new geophysical data of the lake floor has enabled us to reconstruct a highly dynamic outlet glacier of the retreating Fennoscandian Ice Sheet, which played a key role in the damming and drainage of the Baltic Ice Lake during the last deglaciation. 

This work has been funded by the Geological Survey of Sweden (2013-2014). 


East Antarctic Ice Sheet dynamics in the Ross Sea
It is often assumed that the West Antarctic Ice Sheet dominated ice dynamics in the Ross Sea during the last glacial expansion to the continental shelf edge. Recent work in the western Ross Sea and in southern Victoria Land suggest that outlet glaciers of the East Antarctic Ice Sheet may have made major contributions, driving ice flow and retreat dynamics in this sector. With colleagues at Rice University (US) we are investigating:  

i) the role of major East Antarctic outlet glaciers on ice flow and retreat dynamics in the western Ross Sea, 

ii) the role of subglacial meltwater in governing grounding zone stability, 

iii) the role of topographic banks in governing the stability of pattern of the deglaciating ice sheet.

This work is funded by a Swedish Research Council (Vetenskaprådet) junior research grant

Expedition blog: cruise NBP1502 to the western Ross Sea


British-Irish Ice Sheet
The glacial history of the BIIS has long been investigated but for a long time our knowledge has been spatially and temporally patchy. My PhD research approached the problem instead from the ice sheet scale, mapping the complete glacial geomorphological record of Ireland from digital elevation data and satellite imagery. I used this record to reconstruct the geometry and dynamics of the last Irish Ice Sheet and, in a parallel project, Anna Hughes achieved the same for the British Ice Sheet. Our compilation of all published chronological constraints upon ice sheet history from the British Isles, together with our landform-based reconstructions of the ice sheet's development and dynamics, stimulated the NERC Consortium BRITICE-CHRONO project (2012-2017), which aims to constrain the rates and timing of BIIS decay.

Email me for a copy of my thesis
Subglacial bedform maps of Britain and Ireland available from Journal of Maps