RRS James Cook JC123

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS James Cook (740H)
Cruise identifierJC123
Cruise period2015-07-03 — 2015-08-02
Port of departureSouthampton, United Kingdom
Port of returnSouthampton, United Kingdom
ObjectivesCruise JC123 was the second of two cruises on the UK research vessel the RRS James Cook related to the research project BRITICE-CHRONO: constraining rates and style of marine-influenced ice sheet decay. BRITICE-CHRONO is a five-year research project that brings together more than 40 researchers comprising glaciologists, marine and terrestrial Quaternary scientists and ice-sheet modellers. It involves researchers from eight UK universities, plus the British Geological Survey, British Antarctic Survey, NERC's radiocarbon facility and Scottish Universities Environmental Research Centre as well as project partners in Ireland, Italy, Sweden and Norway.

The overall aim of the project is to provide the World's best reconstruction of the demise of a marine-based ice sheet and one that will be critical in developing and testing the next generation of ice sheet models. To achieve this we seek to answer the following research questions:
1. How do marine-based ice sheets deglaciate? By steady, stepped or catastrophic retreat, or partial 'float-off'?
2. What is the main driver(s) of retreat and what is the relative importance of climate change vs. sea level rise?
3. How is ice loss affected as the ice sheet margin crosses the marine-terrestrial transition? Once it back-steps onto land for how long does it stabilise, is it prone to quasi-stable oscillations?
4. What is the glaciological significance of ice rafted detritus (IRD)? This is fundamental for resolving the above because there is current uncertainty as to whether an IRD layer represents ice sheet margin advance or retreat.
5. Which ice sheet model implementations of iceberg calving, grounding line dynamics and ice stream mechanics are best suited for predicting ice sheet retreat?

The focus of BRITICE-CHRONO is on retreat rates from marine-calving to terrestrial-melting margins and this requires that effort is split between these environments. The marine and terrestrial work is fully integrated and follows a common sampling strategy and procedure. Research effort is organised via a series of 8 transects from the continental shelf edge to a short distance (~30 km) onshore. The marine component utilises existing geophysical data archives supplied through our collaboration with the Geological Survey of Ireland and University of Maynooth, and also from British Geological Survey to identify target locations.
Chief scientistColm O'Cofaigh (University of Durham Department of Geography)
Coordinating bodyUniversity of Sheffield
Cruise reportRRS James Cook JC123 cruise report jc123.pdf (60 MB) 
Ocean/sea areas 
GeneralNorth Sea
Inner Seas off the West Coast of Scotland
North East Atlantic Ocean (limit 40W)
SpecificThe Minch. Continental shelf east and west of the Shetlands. North Sea.
Track chartsRRS James Cook JC123 cruise track — jc123trk.pdf (0.62 MB) 
Geology and geophysics 
Core - rockQuantity: number of cores = 179
Description: Vibrocores up to 6 m long and piston cores up to 8 m long.
Multi-beam echosoundingQuantity: track kilometres = 8970
Description: Kongsberg Simrad EM710. Run continuously throughout the cruise and data acquirded along the track shown in the cruise track chart below.
Other geological/geophysical measurementsQuantity: track kilometres = 8970
Description: Kongsberg Simrad SBP120 sub-bottom profiler. Run continuously throughout the cruise and data acquirded along the track shown in the cruise track chart below.