BAS Ref.: JR244 CRUISE REPORT RRS James Clark Ross Cruise JR244 January to March 2011 Marine geoscience and physical oceanography Southern Weddell Sea and South Orkney continental shelf R.D. Larter, C.S. Allen, J.A. Gales, A.G.C. Graham, C.-D. Hillenbrand, D.A. Hodgson, S. Østerhus, V.L. Peck, M.O. Preston, M.W. Robinson, J.P. Robst, M. Ruhnau, J.A. Smith, D. Sprenk and J. Wagner This unpublished report contains initial observations and conclusions. It is not to be cited without written permission of the Director, British Antarctic Survey. i Frontispiece. An Envisat ASAR image showing the Filchner Shelf Ice front region early on 21st February (top) and a view of part of the ice shelf front, with an area of fast ice in the foreground, viewed across the foredeck of RRS James Clark Ross on 20th February. ii Contents Page 1 Summary 1 2 List of Personnel 3 3 Timetable of Events 5 4 Introduction 8 5 Activity Reports 11 5.1 TOPAS and swath bathymetry surveys 11 5.2 Coring for ice sheet history 25 5.3 Quaternary sediment records of glaciation, oceanography 30 and climate 5.4 Water sampling 41 5.5 Seismic profiling 43 5.6 Moorings and Physical oceanography 46 6 List of Scientific Equipment Used 50 7 Equipment Performance 52 7.1 EM120 Multibeam Echo Sounder 52 7.2 TOPAS Sub-Bottom Profiler 53 7.3 EA600 Echo Sounder 54 7.4 EA60 Echo Sounder 55 7.5 Gravity corer 55 7.6 Box Corer 60 7.7 Cable Logging and Monitoring (CLAM) System 62 7.8 CTD System 62 7.9 Seismic reflection equipment 63 7.10 Oceanlogger 65 7.11 Magnetometers 65 7.12 Navigation Systems 66 7.13 NOAA Shipboard Computing System 68 8 ICT and AME Reports 69 9 Acknowledgements 78 10 Acronyms 79 11 Recommendations 80 Appendices A1 Bridge event log 82 A2 Coring station table 103 A3 CTD station table 107 A4 Smear slide list 108 A5 Sieved sediment sample list 109 A6 Typical Sonar System Parameter Settings 112 iii List of Figures Page 1 Track of RRS James Clark Ross during cruise JR244 2 2 Shipboard scientific party at Creek 3, Brunt Ice Shelf 4 3 Cruise JR244 location map showing main working areas 12 4 Survey coverage in the vicinity of the South Orkney Islands 17 5 Survey coverage on the Filchner Trough slope and outer shelf 19 6 Survey coverage on the Filchner Trough inner to mid shelf, and along the 21 western margin of the Caird Coast. 7 Survey coverage at the edge of the Brunt Basin, west of the Brunt Ice Shelf 23 8 Recovery of the IceSheets/Chemistry and Past Climate gravity corer 26 9 Recovery of the BAS box corer 26 10 Bathymetric map of the southern Weddell Sea showing location of the 46 moorings working area 11 Mooring positions 48 12 CTD stations in the southern Weddell Sea 48 13 Temperature (Potential) – Salinity diagram of all CTD casts 49 14 Photograph of heavily inclined seafloor surface in box core BC587 61 15 Photograph of Undisturbed, slightly inclined seafloor surface in box core BC562 61 Tables 1 Summary table of Sound Velocity Profiles (SVP’s) used on JR244 13 2 EM120 surveys 15 3 Cores, CTD’s and water samples on Filchner Trough 650 m water 34 depth transect 4 Cores, CTD’s and water samples on Filchner Trough 1050 m water 34 depth transect 5 Water samples collected and filtered 42 6 Seismic line start and end times and positions 63 7 JR244 Data Logging Events 69 iv 1. Summary On cruise JR244 a programme of marine geological and geophysical work was carried out around the South Orkney Islands and in the southern Weddell Sea for two BAS programmes. In addition, three oceanographic moorings were recovered from the outer continental shelf and slope in the southern Weddell Sea for a University of Bergen-BAS collaborative project. The cruise was combined with BAS logistic activities, which involved uplifting 27 people from Halley Station and a field party of four people from James Ross Island. In view of the long passage necessary to reach the southern Weddell Sea, it was clear that many days of ship time could be saved through combining different activities within a single expedition. During the cruise RRS James Clark Ross ventured further south the ever before, reaching the Filchner Ice Shelf front and carrying out significant research work in that area. The data and samples collected on the cruise will provide new constraints on the maximum extent of glacial ice around the South Orkney Islands and in the southern Weddell Sea during the late Quaternary, the dynamic behaviour of the expanded ice cap and ice sheet, the history of glacial retreat in these areas since the last major advance, and variations in palaeoclimatic and palaeoceanographic conditions in the same areas. Data from the oceanographic moorings that were recovered extend a long-term dataset that has monitored an important input to Antarctic Bottom Water production over a period of more than 30 years. 1 Figure 1. Track of RRS James Clark Ross during cruise JR244 (red) overlaid on shaded- relief display of predicted bathymetry of Smith & Sandwell (north of 72°S; Science, 277, 1956–1962, 1997). Bathymetry south of 72°S is from ETOPO5 global elevation database (http://www.ngdc.noaa.gov/mgg/global/global.html) and Antarctic topographic data is from the Antarctic Digital Database (http://www.add.scar.org). BIS is Brunt Ice Shelf; FIS is Filchner Ice Shelf; FT is Filchner Trough. A larger scale track chart is included as a fold out at the back of this report. 2 2. List of Personnel 2.1 Scientific and Technical (16) R.D. Larter BAS Chief Scientist/Palaeo-Ice Sheets WPM D.A. Hodgson BAS Quaternary Sediments WPM C.-D. Hillenbrand BAS Marine Geologist C.S. Allen BAS Micropalaeontologist/Palaeoceanographer A.G.C. Graham BAS Geophysicist/Geomorphologist V.L. Peck BAS Micropalaeontologist/Palaeoceanographer J.A. Smith BAS Sedimentologist J.A. Gales BAS PhD student (Geomorphologist) S. Østerhus University of Bergen Oceanographer M. Ruhnau University of Hamburg Geophysicist D. Sprenk University of Cologne PhD student (Marine Geologist) J. Wagner University of Hamburg Geophysicist M.O. Preston BAS AME (Electronic Engineer) M.W. Robinson BAS AME (Mechanical Engineer) J.P. Robst BAS ICT (Computing Engineer) F.E. Colgan BASMU Doctor BAS = British Antarctic Survey; AME = BAS Antarctic & Marine Engineering Section; BASMU = BAS Medical Unit; ICT = BAS Information Communications Technology Section; WPM = Workpackage Manager 2.2 Ship’s Company (28) G.P. Chapman Master G.M. Stewart Bosun T.S. Page Chief Officer D.G. Jenkins Bosun’s Mate S.D. Evans 2nd Officer C. Mullaney Seaman P.J. Rosewall 3rd Officer C. Leggett Seaman J.W. Summers Deck Officer J.P. O’Duffy Seaman D.J. Cutting Chief Engineer J.J. McGowan Seaman G. Collard 2nd Engineer P.J. Inglis Seaman J.C. Ditchfield 3rd Engineer M.A. Robinshaw Motorman S.J. Eadie 4th Engineer I.P. Herbert Motorman C.A. Waddicor Radio Officer K.A. Walker Chief Cook S.A. Wright Deck Engineer B.D. Hoult 2nd Cook N.J. Dunbar Electrical Engineer K. Weston Senior Steward J.S. Gibson Purser J. Newall Steward D.W. Lee Steward T.R. Patterson Steward 3 Figure 2. JR244 shipboard scientific party at Creek 3, Brunt Ice Shelf. Back row: R.D. Larter, D.A. Hodgson, J.A. Smith, A.G.C. Graham, C.S. Allen, J.P. Robst, M.W. Robinson, C.-D. Hillenbrand, M. Ruhnau, M.O. Preston, S. Østerhus. Front row: D. Sprenk, J.A. Gales, V.L. Peck, J.Wagner 4 3. Timetable of Events January 2011 22 Embarkation of scientific party at 1400 local time. 23 Unpacking boxes from Scientific Hold. Sunday, so no dockside activity on FIPASS. 24 Mobilisation of gravity corer and University of Hamburg seismic equipment. 25-27 Engineering maintenance. Visit by class from Stanley school on 26th. 28 RRS James Clark Ross departed from FIPASS at 0800 local time (1100Z). Multibeam echo sounder and TOPAS logging started. Coring on slope south of Falkland Islands. Trial deployment of magnetometer. 29 Crossing Drake Passage, collecting multibeam echo sounding and TOPAS data in transit. 30 Completed Drake Passage crossing. Second trial deployment of magnetometer. TOPAS survey in Hesperides Trough. 31 CTD cast and coring in Hesperides Trough. Passage to South Orkney Islands. Initial multibeam echo sounding and TOPAS survey of trough NW of Coronation Island. February 2011 1 Coring and CTD cast in trough NW of Coronation Island, then additional survey. Transit to trough SE of Coronation Island, then initial multibeam and TOPAS survey there. 2 Completed initial survey for trough SE of Coronation Island. Coring in trough. 3 Seismic profiling along trough SE of Coronation Island. Coring in trough. 4 Passage to southern Weddell Sea, collecting multibeam echo sounding and TOPAS data in transit. Magnetometer deployed. 5 Continued passage. 6 Completed passage to southern Weddell Sea. Recovered magnetometer. TOPAS survey to select core site on Deutschland Canyon levee. 7 Completed TOPAS survey. Coring and CTD cast on levee. Transit to next station, further up-canyon on same levee, then TOPAS survey there. 8 CTD cast and coring on levee. EM120 roll and pitch calibration. STCM started. Start of transit to next station, again further up-canyon on same levee. 9 Continued transit to next station. Slow progress due to ice conditions. 5 10 CTD cast and coring on levee. Transit to shelf edge region. 11 Multibeam and TOPAS survey along shelf edge. CTD cast and box core on flank of Filchner Trough.