RRS James Cook JC106
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS James Cook (740H) |
| Cruise identifier | JC106 |
| Cruise period | 2014-07-18 — 2014-08-25 |
| Status | Completed |
| Port of departure | Southampton, United Kingdom |
| Port of return | Southampton, United Kingdom |
| Purpose | Research |
| Objectives | JC106 was the first 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 underlying rationale behind BRITICE-CHRONO is concern about the retreat/stability of the marine-influenced West Antarctic and Greenland ice sheets, and consequent sea-level rise. It is imperative that we can predict the future rates of change of these large ice masses but our current ability to do so is limited and a weakness in climate science. Numerical ice sheet models - capable of making predictions have yet to be adequately tested against data on the pattern and timing of a shrinking ice sheet. Although recent work has constrained the pattern of retreat of the ice sheet that once covered Ireland and Britain (Clark et al., 2012, Quaternary Science Reviews), the timing of that retreat is inadequately constrained. BRITICE-CHRONO is a systematic and directed campaign to collect and date material to constrain the timing and rates of change of the British-Irish Ice Sheet (BIIS). Retreat of the BIIS will become the best constrained anywhere and be the benchmark against which predictive ice sheet models are improved and tested, thus contributing greatly to glaciology, climate and Quaternary science and the veracity of predictions of sea-level change. 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. JC106 on the RRS James Cook in 2014 was the first of two BRITICE-CHRONO research cruises. It focused on Celtic and Irish seas, the northern approaches to the Barra Fan, the Malin Sea and the NW and western Irish shelf (transects 3, 4, 5, 6 and 7). Multibeam swath bathymetry, sub-bottom profiler data, British Geological |
| Chief scientist | Colm O'Cofaigh (University of Durham Department of Geography) |
| Project | BRITICE-CHRONO: constraining rates and style of marine-influenced ice sheet decay |
| Coordinating body | Department of Geography, University of Sheffield |
| Cruise report |  (13.37 MB) |
| Ocean/sea areas | |
| General | Irish Sea and St. George's Channel Celtic Sea North East Atlantic Ocean (limit 40W) |
| Specific | UK and Ireland continental shelf |
| Track charts | (0.20 MB) |
| Measurements | |
| Geology and geophysics | |
| Core - rock | Quantity: number of cores = 223 Description: Vibrocores up to 6m long and piston cores up to 8m long |
| Multi-beam echosounding | Quantity: track kilometres = 8000 Description: Kongsberg Simrad EM710. Run continuously throughout the cruise and data acquired along the cruise track. |
| Other geological/geophysical measurements | Quantity: track kilometres = 8000 Description: Kongsberg Simrad SBP120 sub-bottom profiler. Run continuously throughout the cruise and data acquired along the cruise track. |
