RRS James Clark Ross JR20150130 (JR298)
Cruise summary report
|Ship name (ship code)||RRS James Clark Ross (74JC)|
|Cruise identifier||JR20150130 (JR298)|
|Cruise period||2015-01-30 — 2015-03-04|
|Port of departure||Punta Arenas, Chile|
|Port of return||Punta Arenas, Chile|
|Objectives||The main purpose of cruise JR298 was to collect marine geological and geophysical samples and data to support International Ocean Discovery Program (IODP) proposal 732-Full2, "Sediment drifts off the Antarctic Peninsula and West Antarctica" (Channell, Larter, Hillenbrand et al). The ship time was allocated for this purpose on the basis of a Site Survey Investigation grant from the NERC UK-IODP Programme (NE/J006548/1: Depositional patterns and records in sediment drifts off the Antarctic Peninsula and West Antarctica) to R.D. Larter, C.-D. Hillenbrand (both BAS), D.A. Hodell (University of Cambridge) and A.G.C. Graham (University of Exeter). The data and samples collected will also be used in two Collaborative Gearing Scheme projects, an Antarctic Science Bursary project, a University of Cambridge PhD studentship, and within the National Capability remit of the BAS Science Teams in "Geology and Geophysics" and "Palaeoenvironments and Climate Change".
These projects are:
- Tracing and reconstructing the neodymium and carbon isotopic composition of circum-Antarctic waters (CGS-100, PI: A.M. Piotrowski, Department of Earth Sciences, University of Cambridge; cruise participants: A.M. Piotrowski and T.J. Williams).
- Structural characterisation of Late Quaternary sediments from West Antarctic contourite drifts using three dimensional X-ray imaging (CT-scanning) (CGS-98, PI: C. Ó Cofaigh, Department of Geography, Durham University; cruise participant: J. Horrocks)
- Tracing the Quaternary evolution of the Antarctic Peninsula and West Antarctic Ice Sheets using lead isotopes in ice-rafted feldspar mineral grains (Antarctic Science Bursary awarded to C. Cook).
- Seismic imaging of oceanographic structures and processes in the Southern Ocean south of the Polar Front (component of University of Cambridge/BP Institute PhD studentship; primary supervisor: N.J. White, Department of Earth Sciences, University of Cambridge; PhD student and cruise participant: K.L. Gunn).
- Modelling crustal structure across the Bellingshausen Gravity Anomaly and oceanic fracture zones formed at the Antarctic-Phoenix Ridge through integration of marine potential field and seismic data (Collaboration between two BAS Science Teams; cruise participant: T.A.R.M. Jordan).
The cruise also provided support for physical oceanography projects by deploying six Argo floats and rescuing a malfunctioning sea glider.
Towards the end of the cruise, RRS James Clark Ross was diverted to Rothera to uplift 16 personnel who had been flown across from Halley in two ALCI Basler aircraft because the sea ice situation in the Weddell Sea was considered to pose a significant risk to the scheduled last call of the season at Halley by RRS Ernest Shackleton. This uplift resulted in a two-day delay to arrival at Punta Arenas at the end of the cruise, which was in addition to a two-day extension already agreed as a result of departure from Punta Arenas having been delayed by slow refuelling.
Adverse weather conditions, particularly during the first half of the cruise, resulted in more downtime than the amount of contingency time that had been allowed in the proposal. As a result, one less piston core and about 20% fewer line-km of seismic data were collected than had been planned. Nevertheless, the key objectives were achieved and the cores and data that were collected are of very good quality. The data and cores collected on cruise JR298, combined with existing data and cores, should satisfy all of the requirements of the Site Characterisation Panel and the Environmental Protection and Safety Panel of IODP. They will also provide a good basis for addressing the science objectives set out in the UK-IODP Site Survey Investigation proposal and those of the ancillary projects listed above.
|Chief scientist||Robert D Larter (British Antarctic Survey)|
|Coordinating body||Natural Environment Research Council (NERC)|
|Cruise report||(11.91 MB)|
|Specific||Southern Bellingshausen Sea. Pacific margin of the Antarctic Peninsula|
|Track charts||(0.70 MB)|
|Surface measurements underway (T,S)||Quantity: activity duration in days = 29|
Description: BAS oceanlogger, temperature, conductivity
|Bathythermograph||Quantity: number of profiles = 11|
Description: Expendable CTDs (XCTD-1 probes)
|Bathythermograph||Quantity: number of profiles = 23|
Description: Expendable bathythermograph (19 x T5 probes and 4 x T7 probes)
|CTD stations||Quantity: number of stations = 5|
Description: Seabird SBE9plus CTD including fluorometer, oxygen sensor, PAR sensor, transmissometer, altimeter, LADCP and rosette of 24 x 12 l Niskin bottles
|Current profiler (eg ADCP)||Quantity: activity duration in days = 29|
Description: RDI 75 kHz ADCP
|Biology and fisheries|
|Acoustic reflection on marine organisms.||Quantity: activity duration in days = 23|
Description: Kongsberg EK60, backscatter amplitude
|Routine standard measurements||Quantity: activity duration in days = 29|
Description: BAS oceanlogger, temperature, pressure, wind speed and direction
|Geology and geophysics|
|Core - soft bottom||Quantity: number of stations = 7|
Description: Piston cores up to 13 m in length
|Core - soft bottom||Quantity: number of stations = 8|
Description: Box cores
|Single-beam echosounding||Quantity: activity duration in days = 28|
Description: Kongsberg EA600, water depth and reflection amplitude
|Multi-beam echosounding||Quantity: activity duration in days = 28|
Description: Kongsberg EM122, water depth, backscatter amplitude and some water column data
|Multichannel seismic reflection||Quantity: track kilometres = 1960|
Description: Multichannel seismic. Mostly using 2400 m (192 channel) streamer. Some lines acquired using 1200 m (96 channel) streamer. Source was 2 x 150 cu. in. GI guns firing in harmonic mode. Data recorded in SEGD format with 1 ms sampling interval.
|Gravity measurements||Quantity: track kilometres = 5166|
Description: Micro-g LaCoste Air-Sea System II gravity meter S/N S84
|Magnetic measurements||Quantity: track kilometres = 3005|
Description: SeaSpy Overhauser towed magnetometer
|Other geological/geophysical measurements||Quantity: activity duration in days = 27|
Description: TOPAS PS018 parametric sub-bottom profiler, reflection amplitude and travel time
|Moorings, landers, buoys|
|Neutrally buoyant floats||58° 24' 24" S 66° 6' 11" W — Argo float S/N 5595: temperature, salinity, depth, position|
|Neutrally buoyant floats||59° 31' 0" S 66° 41' 41" W — Argo float S/N 7018: temperature, salinity, depth, position|
|Neutrally buoyant floats||68° 56' 35" S 85° 47' 24" W — Argo float S/N 7020: temperature, salinity, depth, position|
|Neutrally buoyant floats||61° 40' 29" S 67° 50' 48" W — Argo float S/N 7022: temperature, salinity, depth, position|
|Neutrally buoyant floats||63° 26' 30" S 68° 51' 24" W — Argo float S/N 7021: temperature, salinity, depth, position|
|Neutrally buoyant floats||60° 30' 35" S 67° 16' 48" W — Argo float S/N 7019: temperature, salinity, depth, position|