IMMEDIATE SCIENCE REPORT
K042: Oceanography and Sedimentation beneath the McMurdo/Ross Ice Shelf in Windless Bight
Antarctica New Zealand 2002/03
1. Popular Summary of Scientific Work Achieved
This project investigated water flow and sedimentation beneath the McMurdo Ice Shelf south of Ross Island. Its purpose is to help understand the past (and future) behaviour of the huge Ross Ice Shelf, which lies immediately to the south. Team members from the Alfred Wegener Institute used a hot water drilling system (Nixdorf et al., 1994) to melt 0.6-m-wide access holes through the ice shelf in two locations 5 and 12 km east of Scott Base, thus allowing measurements and samples to be taken from the water column and sea floor beneath. The sites are relatively remote, being covered by ice 70 and 143 m thick and with sea floor 926 and 923 m below sea level respectively.
Water column measurements from the two locations show that the main current direction is to the east from McMurdo Sound through to the Ross Ice Shelf, with speeds averaging 5 to 7 cm/sec but at times reaching 17 cm/sec. Flows at a third and shallower location at the ice shelf edge below the sea ice off Scott Base were much stronger – up to 60 cm/sec. Water column profiles of salinity and temperature are similar to those found 25 years ago at the first ever hole drilled through the Ross Ice Shelf 400 km south at J9. These waters are some of the coldest and densest in the world, helping drive deep ocean circulation as they flow north into the Pacific Ocean.
The sea floor at both sites is soft mud with siliceous algae and calcareous microfossils. The former are well known in open Ross Sea surface waters, being swept in by currents. The latter live in mud and were not expected because of the cold and deep corrosive waters. One of the cores passed down into a stony glacial deposit believed to represent sediment released from basal ice grounded nearby more than 10,000 years ago when ice filled most of the Ross Sea after the last glaciation. However penetration of low energy (3.5 kHz) seismic waves 300 m into the soft sea floor shows that the sites are likely to have been too deep to have been compacted or eroded by grounded ice. This observation, together with the fine-grained nature of the sediment confirms the basin's suitability for the planned 1000-m-deep ANDRILL hole for recovering a long and sensitive record of Ross Ice Shelf history. Current speeds in the water column also indicate its technical feasibility.
Fig.1 Hut Point Peninsula and the McMurdo Ice Shelf to the SE, showing the bathymetry of the broad channel connecting the waters of McMurdo Sound to the NW with those beneath the Ross Ice Shelf to the east. The intersecting lines mark seismic surveys run by the Institute of Geological & Nuclear Sciences (Melhuish et al., 1995; Bannister and Naish, 2002; Horgan et al., 2003) for imaging the geometry of the strata filling the basin (see fig. 2). The red square is the current monitoring site at the shelf edge.
2. Proposed Programme
This project was designed both to investigate the little explored sub-ice shelf environment and to provide essential site data for coring 1000 m into the sea floor by ANDRILL (Lacy et al., 2003) for a history of the McMurdo-Ross Ice Shelf (MRIS). Ross Island has been depressing the crust under its own weight for at least the last million years, and at the same time has been acting as the western pinning point for the MRIS. As a result sediment has been accumulating in a sea floor depression over 900 m deep to the south of Ross Island in Windless Bight (Fig. 2). These sediments record the presence and possible past absence of the MRIS, and the movement of Ross Sea Shelf Water behind Ross Island between McMurdo Sound and the central Ross Sea.
We proposed to occupy 4 sites, first melting a 50-cm-wide hole through the ice shelf (70 to 150 m thick). We then proposed to measure water depth (expected to be over 800 m) and water column properties through a tidal cycle (conductivity, temperature, current speed, current direction) before sampling the sea floor by grab and gravity corer. The access hole was to be melted by a Hot Water Drilling system provided by the Alfred Wegener Institute for Polar and Marine Research, which had been delivered by ship the previous summer.
The project ran extremely well with access holes drilled and kept open through the ice shelf for up to 9 days (for a full account see the Logistics Report). This was critical for the success of the project. All instruments and sampling devices deployed through the access holes functioned and were recovered. The two most central of the 4 proposed sites were occupied, and a third site at the edge of the ice shelf monitored over a period of three weeks for currents in the upper 2/3 of the water column.
Hot water capacity: 90 l/min from 6 JP8 fueled burners
Water temperature: 95°C
Working pressure: 80 bar (1200 psi)
- Pilot hole (~150 mm diameter) 30 m/hr
- Reamer hole (>600 mm diameter) 20 m/hr
- Bottom reamer (>600 mm diameter 5 m/hr
Fig 3. The system uses a combination of melted snow and re-circulated melt-water to produce a jet of hot (95°C) water to melt through the ice shelf. Firstly a vertical pilot hole (~15 cm) is made through the ice shelf. This is then widened to >600 mm using a reamer. Additional reaming is needed at the bottom of the hole as hot water is lost to the ocean beneath the ice shelf.
3. Scientific Endeavours and Achievements
The data and sample gathering phase of the Windless Bight project has now been successfully completed. Some results are immediately apparent and are summarised below. Others require further data reduction and analysis. Roles and responsibilities for the field phase just completed are shown in Table 1.
|Peter Barrett, VUW||Scientific Leader||Overall programme & scientific report.|
|Alex Pyne, VUW||Field Leader||Field programme and logistics report. Setting and retrieving oceanographic instruments and bottom sampling equipment. Analysis of current measurements for sea riser modeling.|
|Gavin Dunbar, VUW||Scientist||Assistance with setting and retrieving oceanographic instruments. Visual core description. Sampling of bottom sediments. Subsequent textural analysis and organisation of supporting analyses|
|Lionel Carter, NIWA||Scientist||Assistance with setting and retrieving oceanographic instruments. Analysis of water column CTD data|
|Natalie Robinson, VUW||Scientist||Analysis of water column current data.|
|Christina Riesselman, Stanford U||Scientist||Analysis of water and particulate chemistry from the water column. Microfossil analysis of water column particles and sea floor sediment.|
|Giovanna Giorgetti, Siena||Scientist||Petrographic analysis of bottom sediments|
|Frank Niessen, AWI||Scientist||Acoustic sounding, gravity coring. Sediment physical properties (including shear strength)|
|Uwe Nixdorf, AWI||Engineer HW drilling||Drilling and maintaining access holes. Ice shelf observations.|
|Erich Dunker AWI||Asst Eng HW drilling||Drilling and maintaining access holes, Development of gravity corer|
|Jonathan Leitch, VUW||Eng plant & camp||Maintaining plant and camp operations|
|Dougal Mason,VUW||Field assistant||Assisting drilling access holes|
Camp was set up on the first site at the intersection of seismic lines MIS-1 and MIS-2 on January 3. However, because the site was too close to one of the approaches to a runway on Williams Field it had to be moved 1.75 northward along the seismic line to 77° 53 308′S; 167° 17.753′E and was designated HWD03-1 or Site 1 (Fig. 1). At the same time a Broadband ADCP current meter was installed in sea ice at the edge of the ice shelf south of Scott Base (77° 52.773″S; 166° 50.042′E) to record currents to 400 m depth continuously over the following 3-4 weeks. The hole at Site 1 was drilled on January 11 and after 4 attempts successfully reamed finally on January 12 (midnight) to a diameter of > 0.56 m throughout. Measurements and sampling through the hole took place from January 13 to 22. On January 23 and 24 the camp was shifted 7 km northeast to the second site to be occupied (HWD03-2 or Site 2). The access hole was drilled on January 26, reamed finally on January 27 (22:00) and kept open until February 2 for measurements and sampling. Camp and equipment were returned to Scott Base and the field operation completed by February 4.
|HWD-1 - 5 km from edge of shelf|
|Position:||77° 53.308′S||167° 05.067′E|
|Ice Shelf thickness||70.5+−0.1 m|
|Datum - Ice Shelf surface||0 m|
|Firn-ice transition||27.0+−0.5 m|
|Sea level depth||17.3+−0.2 m|
|Sea floor depth by wire line||938 m (920 m bsl)|
|HWD-2 - 12 km from edge of shelf|
|Position:||77° 50.111′S||167° 20.209′E|
|Ice Shelf thickness||143.7+−0.1 m|
|Datum - Ice Shelf Surface||0 m|
|Firn-Ice Transition||27.2 +−0.2 m|
|Sea level depth||27.6 m|
|Sea Floor Depth by wire line||950.7 m (923 m bsl)|
OCEANOGRAPHIC AND SEA FLOOR MEASUREMENTS
The first measurements at Site 1 were to establish water depth and nature of the sea floor. A 3.5 kHz transducer was lowered and set 2 m below the base of the ice shelf to obtain a high quality acoustic record of the sea floor and subsurface sediment. Water depth was determined to be 855 m below the base of the ice shelf (908 m bsl, 926 m below the ice shelf surface, a convenient reference point for all subsequent oceanographic measurements). The sea floor reflector was sharp and stratification recognized down to a depth of over 300 m. This indicates that the sediment for this interval is largely fine-grained and unconsolidated. The water depth was determined by weighted line to be 938 m, 12 m deeper than the acoustic estimation. This depth was used for operational purposes on oceanographic casts. A similar procedure was followed for site 2, and an outline of the scientific data gathered for both sites is shown in table 3.
Fig. 4. Seismic record through Site 1 (MIS-1 line, Bannister et al., 2002), with image from 3.5kHz profiler inserted. Reflectors can be seen down to ~300 m below the sea floor.
|DEVICE||MEASUREMENTS OR SAMPLES TAKEN||HWD03-1||HWD03-2|
|3.5 kHz sounder||Water depth and sub-seafloor stratigraphy||Penetration to ~300 m||Ice shelf too thick for cable|
|S4||Current speed and direction profiles through the water column||Casts 1 to 13 from 1400 Jan 14 to 1700 Jan 16||Casts 1 to 10 from 1110 Jan 28 to 1240 Jan 29.|
|CTD||Conductivity and temperature profiles through the water column|
|NIO bottles (1 litre)||Water samples for chemistry and suspended particulate matter||~20 samples taken at 6 levels||~20 samples taken at 6 levels|
|ADCP array||Current speed and direction measured simultaneously through the water column for at least 48 hours||Deployed for 87 hours on Jan 1822. See Fig. 3||Deployed for 47 hours on Jan 31 to Feb 1|
|Gravity cores||48 mm diameter sediment cores – at least 3 from each site more than 50 cm long||Cores 7, 11, 13, 50, 60 and 61 cm||Cotes 29, 42, 61 and 63 cm|
|Grab||Top 3-5 cm from sea floor.||Grabs 1 and 2 empty. Grab 3 30% full.||Grabs 1 & 2 empty. Grab 3 full|
Cast procedure and water/particulate chemistry samples: After a trial cast with the S4 1 m above the weighted end of the line and the CTD 5 m above that, a second cast was run with 1 litre NIO bottles at depths at 6 levels through the water column for water sampling. Several bottles proved difficult to bring up through the hole because currents in the water column deflected the rope, and were damaged. It was then decided to attach only two bottles 5 m apart and 5 m above the CTD on each cast but to trip them each cast at successively higher levels to cover the 6 planned sampling levels. This worked well, and the 14 casts were completed late on January 16. Filtration was done on samples from each level for 3 casts with a fourth close to the sea floor, and 3 further samples from water in the gravity corer just above the sediment water interface. Material could be seen on all filters, with those close to the sea floor showing an obvious brown coating. Samples were also taken for water chemistry.
CTD measurements: Oceanographic data were collected at both sites primarily with a Conductivity-Temperature-Depth profiler during water sampling casts, and later by a moored array of Acoustic Doppler Current Profilers (ADCPs). The setup and some results are shown in figure 5.
|Zone||Depth range [m]||Salinity [psu]||Temperature [°C]|
|A||53 - 150||34.38 to 34.46||−1.915 to −1.90|
|B||111- 275||34.59 to 34.63||− 1.93 to −1.936|
|C||260 - 660||34.65 to 34.67||−1.918 to −1.914|
|D||660 - 922||34.70 to 34.71||− 1.911|
Zones B, C and D resemble High Salinity Shelf Water (HSSW) and Deep Ice Shelf Water (DISW) of Jacobs et al. (1985), whereas Zone A resembles Shallow Ice Shelf Water (SISW). Site J9, 450 km south of the Ross Ice shelf, has a similar Temperature/Salinity structure suggesting continuity of water masses with Windless Bight. However, the shallowest zones are much colder at J9 and lack the relatively warm intrusion (Zone A) seen in the Bight.page 7
Current velocity measurements: Current measurements from the ADCP arrays are heavily influenced by the diurnal tides (Fig 5). Currents are relatively slow in the floor of the basin at both sub-ice shelf sites (averaging around 7 cm/s with a maximum of 17 cms), but are considerably faster (up to 60 cm/s) at the ice shelf edge off Hut Point Peninsula where the water is shallower (~600 m). Flood tides flow to the E and swing S and W below the McMurdo Ice shelf. This is also the direction of the mean flow, suggesting that, like the western and central Ross Ice Shelf edge, McMurdo Sound may also be a point of sub-ice shelf inflow.
Sea floor sediments: Initial gravity coring attempts yielded cores only a few cm long but by applying grease to the inside of the core liner cores in excess of 50 cm were consistently recovered page 8 from both sites. Grab samples of the top 2-3 cm were also recovered from both sites, and showed that the sea floor sediment at each comprises a thin (5 mm) layer of sandy mud with scattered basaltic pebbles up to 15 mm across. The sediments beneath are diatomaceous sandy mud with diverse diatoms, occasional foraminifera and rare shells. The mud gives way at 31 cm at Site 1 and 60 cm at Site 2 to a pebbly sandy mud or diamicton beneath (Fig. 6). Cores from Site 1 have from 23 to 30 cm an unusual laminated well sorted sand with a sharp base and top, tentatively interpreted as a sediment gravity flow. The diamicton in the lower part of each core was firm but not over-consolidated, indicating that the basal ice that deposited the sediment did not load or erode the sea floor.
The sand mineralogy is basaltic glass and rock fragments throughout both cores, but they also have a significant proportion of quartz, some of it rounded like grains in the Beacon sandstone from the Transantarctic Mountains 100 km to the west. Smear slides also show a trend of increasing biogenic silica up the core. While further work is needed these results are support the view that the cores represent a period of glacial retreat from a time of more extensive grounded ice, effectively recording ice retreat since the Last Glacial Maximum, a pattern consistent with cores elsewhere in the Ross Sea. A combination of field evidence and ice sheet modelling indicates that the last stage of the retreat to the present position of the ice margin on either side of Ross Island took place between 8000 and 4000 years ago (Kellogg et al., 1996)
- water column data that show the prevailing tidal nature of the sub-ice shelf flow, but with a net inflow from McMurdo Sound into Windless Bight. The temperature/salinity structure is very similar to site J9, suggesting continuity of water masses beneath the entire ice shelf, with McMurdo Sound being another possible point of inflow.
- Cores penetrated a thin Holocene mud blanket overlying soft diamicton recording the retreat of the ice that filled McMurdo Sound until around 6000 years ago.
The lack of sediment compaction indicated by 3.5 kHz penetration to 300 m bsf shows that water was deep enough not to have grounded ice during the Last Glacial Maximum (or for previous such events for perhaps as much as a million years or more). These data indicate that the basin contains a long and continuous record of the presence, absence and (near) grounding of the Ross Ice Shelf over the last million years or more. One of ANDRILL's goals is to core this record.
Further work on the oceanographic data will help understand the origins and maintenance of oceanic circulation under the present global climate regime. It will also help in designing ANDRILL's deep coring system, with deployment planned for 2005-06.
Bannister, S. and Naish, T.R. 2002. ANDRILL Site Investigations, New Harbour and McMurdo Ice Shelf, Southern McMurdo Sound, Antarctica. Institute of Geological and Nuclear Sciences Report 2002/01, 24 p.
Domack, E.W., Jacobson, E.A., Shipp, S. and Anderson, J.B. 1999. Late Pleistocene-Holocene retreat of the West Antarctic Ice Sheet system in the Ross Sea: Part 2 – sedimentologic and stratigraphic signature. Geological Soc. America Bull., 111, 1517-1536.
Horgan, H., Naish, T., Bannister, S., Balfour, N., Wilson, G., Finnemore, M. and Pyne, A. 2003. Seismic stratigraphy of the Ross Island flexural moat under the McMurdo-Ross Ice Shelf, Antarctica. Immediate Scientific Report to AntarcticaNZ
Jacobs, S.S., Fairbanks, R.G. and Horibe, Y., 1985. Origin and evolution of water masses near the Antarctic continental margin: evidence from H218O/H216O ratios in seawater, American Geophysical Union Antarctic Research Series, vol. 43, 59-85.
Joughin, I. and Tulaczyck, S. 2001. Positive mass balance of Ross Ice Streams, West Antarctica. Science, 295, 476-480page 9
Kellogg, T.B., Hughes, T. and Kellogg, D.E. 1996. Late Pleistocene interactions of East and West Antarctic ice-flow regimes: evidence from the McMurdo Ice Shelf. Journal of Glaciology, 42, 486-499.
Lacy, L, Harwood, D. and Levy, R. (eds.), 2002. Future Antarctic Margin Drilling: Developing a Science Program Plan for McMurdo Sound. Andrill Contribution 1. University of Nebraska-Lincoln, Lincoln, NE xxx pp.
Meluish, A, Henrys, S.A., Bannister, S. and Davey, F.J., 1995. Seismic profiling adjacent to Ross Island: constraints on Late Cenozoic stratigraphy and tectonics. Terra Antartica, 2, 127-136.
Nixdorf, U., Oeter, H. and Miller, H., 1994. First access to the ocean beneath Ekströmisen, Antarctica, by means of hot-water drilling. Annals of Glaciology, 20, 110-114.
Work planned on data and samples collected by K-042 is outlined in Tables 4a and b below.
|Lead authors||Institution||Nature/content of report/paper|
|P Barrett||VUW||Scientific Report to AntarcticaNZ.
Poster for AGU/EGA/EUG, Nice (with help from G. Dunbar & others).
|P Barrett||VUW||Scientific Report on McMurdo Ross Ice Shelf study
VUW publication with contributions from whole party
|A Pyne||VUW||Logistics Report to AntarcticaNZ.
Report to ANDRILL on current measurements for design of sea riser.
|G Dunbar||VUW||Sedimentation beneath the McMurdo/Ross Ice Shelf. Input from Barrett, Carter, Giorgetti, Neissen, Pyne, Riesselman.|
|G Dunbar||VUW||History of the MRIS since the LGM (input from all) for Science or similar|
|L Carter||NIWA||Oceanographic measurements and implications for sediment transport (input from G. Dunbar, R.Dunbar, A Pyne, C Riesselman, N Robinson and M. Williams)|
|N Robinson||VUW||Thesis and paper on description and modelling of currents between Ross and White Islands. (input from Barrett, Carter, Dunbar, McGuinness, Pyne, Williams).|
|G. Giorgetti||U Siena||Provenance of bottom sediment beneath MRIS (input from Barrett, Carter, G. Dunbar), including petrography, chemical analysis of seds by XRF (input from Giorgetti, GDunbar, C Reisselman|
|F Niessen||AWI||Nature of the sedimentary sequence beneath MRIS based on site seismic data and physical properties.(input from Alex Pyne and Tim Naish)|
|U Nixdorf||AWI||Platelet ice beneath MRIS|
|U Nixdorf||AWI||Hot water drilling through MRIS (with input from Erich Dunker).|
|Lead authors||Institution||Nature/content of report/paper|
|W Ehrmann||AWI||Clay species and their proportions from core samples|
|H von Eynatten||U Jena||Paleoclimate from chemical alteration of volcanic granules from core samples|
|H Helmer||AWI||Regional ocean currents incorporating MRIS data|
|(FN to arrange)||AWI||Secular variation from depositional remnant magnetization measured in whole core|
|(LC to arrange)||NIWA||Trace element characterization of sponge spicules|
|D Damiani||U Siena||Morphoscopic and textural study of quartz grains by SEM|
|D Damiani||U Siena||Structural and chemical compositional analyses of clay minerals by XRD and TEM-AEM|
|F Talarico||U Siena||Petrography of clasts by microscope and SEM|
We thank Antarctica New Zealand for its support before, during and after the field operation, and for the support during the field phase from the Scott Base staff under the leadership of Dene Robinson (Base Leader), Ma Peters (Base Manager) and Keith Springer (Operations Manager). Willing assistance was also given by Doug Bell, Steve Brown, Kim Dudek and Peter Wederall at various stages in the operation. We were also fortunate to have erstwhile Scott Base staffer "Johno" Leitch as a member of the K-042 team "Woody" Woodgate in Christchurch ensured that equipment arrived on schedule, as well as responding with his usual calmness and efficiency to unplanned and unexpected needs.
We are especially grateful to the Alfred Wegener Institute for the provision of the hot water drilling system, whose efficient operation was essential to the success of the program. We are also grateful to AWI for the gravity corer and winch, Stanford University for two of the Acoustic Doppler Current Profilers and NIWA for the CTD and ancillary oceanographic equipment.
We also acknowledge the support of a number of funding agencies, including the NZ Foundation for Research Science and Technology for its support for the VUW component of the project, as well as support from the home institutions of all participants.
The diagrams in this report were created largely by Gavin Dunbar for a poster for the joint AGUEAG-EGU meeting in Nice, France in April 2003. The poster can be downloaded from: ftp://ftp.geo.vuw.ac.nz/CAPE/outgoing/AGUNicePoster.pdf.
*EVENT DIARY (FROM DRAFT LOGISTICS REPORT)
|Date||Main Activities and Location||Other Comments|
|16-30 Dec.||Preparing Aalener sledge for Hot Water Drill at Scott Base||Johno Leitch|
|Preparing Camp Containers, CRP DS Lab and equipment at Scott Base||Johno Leitch, SB staff.|
|30 Dec.||E. Dunker, U. Nixdorf, A. Pyne; Chch to Scott Base|
|31Dec.-4 Jan.||Assembly and testing equipment at SB -Willy Rd. transition. Preparing traverse loads||Assisted by SB plant ops. (Kim and Gus)|
|4 Jan.||G. Dunbar, D. Mason; Chch to Scott Base|
|3-5 Jan.||Traverse equipment to MISHWD-1 site. Start camp setup.|
|5 Jan.||Move site west along seismic line to HWD-1 site.|
|6 - 7 Jan.||Camp setup, Vehicle licences, started making water with HWD|
|7 Jan.||P. Barrett, L. Carter, G. Giorgetti, F. Niessen, C. Riesselman, N. Robinson; Chch to SB|
|8- 12 Jan.||Drilled HWD-1 hole. Down hole reamer fitting lost and new hole drilled 3 m away|
|8 Jan.||Preparing equipment and laboratory operation at Scott Base.|
|10 Jan.||Sea ice site for Broadband Deployment, site BB2, Kassbohrer drilled hole.|
|11 Jan.||BB2 site, recovered instrument for checking and set up snow box (box brownie) around hole.|
|14 Jan.||HWD-1. Started current meter (S4) and water bottle sampling. Winch motor problems, used skidoo. Multiple water bottle array stuck under ice, recovered at slack water.|
|15-16 Jan.||Winch operating with SB electric motor. 24 hour current profiling and water sampling.|
|16-17 Jan.||Completed current profiling and water sampling. Calliper log of hole and coring and grab of sea floor. Reamed hole for ADCP mooring.|
|18 Jan.||Deployed ADCP mooring. Some personnel return to Scott Base.|
|19 Jan.||Fuelling and camp maintenance.||Johno camp caretaking|
|20-21 Jan.||Storm, condition 1-2 on Willy Rd. Some personnel return to HWD-1 camp on 21 Jan. during short weather break.|
|22 Jan.||Dig out and recover ADCP mooring (86 hour duration). Personnel to HWD-1 camp for instrument download.|
|23 Jan.||Start camp pack up and move. HWD-2 site located and camp moved for overnight occupation. Some personnel to Scott Base.||Johno and Gus|
|24 Jan.||Set up Hwd-2 campsite. Move remaining equipment form HWD-1 to HWD-2 site.|
|25 Jan.||Preparing HWD equipment, make start-up water and complete camp setup. Personnel to site|
|26 Jan.||Drill HWD-2. Ice thickness approx 144 m.|
|27 Jan.||Reaming hole||Visitors from SB|
|28 Jan.||Started 24 current profiling and water sampling|
|28 Jan.||L. Carter return Chch.|
|29 Jan.||Completed water column profiling. Coring and grab sampling of the sea floor||Visitors from Crary Lab & McMurdo.|
|30 Jan.||Calliper log and reaming hole. Prepare ADCP mooring.|
|31 Jan.||Deploy ADCP mooring Caretaking at site, some personnel return to SB and return to site.|
|1 Feb.||Personnel to site for mooring recovery, recover mooring started at 2300 hrs.|
|2 Feb.||3.5Khz and further coring of the sea floor. Preparing instruments for return to NZ and transport to Scott Base.|
|3 Feb.||Set up mini HWD on Hagglund sledge for sea ice mooring recovery. Recover sea ice BB ADCP.|
|4 Feb.||Break camp and start return of equipment to the SB transition.|
|5 Feb||Packing for Ship Cargo, returning camp/equipment to SB|
|5 Feb.||P Barrett return Chch.||page 13|
|6 Feb||Helicopter recon. To New Harbour and Black Island, proposed ANDRILL sites. (Dunker, Nixdorf & Pyne)|
|7-9 Feb.||Packing up equipment and laboratories at Scott Base.|
|9 Feb.||F. Niessen & A. Pyne return to Chch.|
|10 Feb.||G. Dunbar, E. Dunker, G. Giorgetti, J. Leitch, D. Mason, U. Nixdorf, C. Riesselman & N. Robinson return Chch.|