RRS James Clark Ross JR20120708 (JR269B)
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS James Clark Ross (74JC) |
| Cruise identifier | JR20120708 (JR269B) |
| Cruise period | 2012-07-07 — 2012-07-24 |
| Status | Completed |
| Port of departure | Reykjavík, Iceland |
| Port of return | Reykjavík, Iceland |
| Purpose | Research |
| Objectives | Cruise JR269B was the second leg (the first being JR269A in late summer 2011) of a programme to investigate methane hydrate accumulation beneath, and methane venting from, the sea bed in an area on the western margin of the Svalbard archipelago. This area is being studied by a number of laboratories and programmes in order to gain better understanding of the relationships between sea floor temperature changes, the methane hydrate stability zone beneath the sea floor, the presence, formation and dissociation of methane hydrate, the nature and distribution of fluid escape features at and beneath the sea floor, and the resulting fluxes of methane into the water column and atmosphere.
The specific objective of this project is to improve estimates of the total amounts of methane and hydrate involved in this process by quantifying the porosity, and the saturation of that porosity with either methane gas or methane hydrate, in the upper few hundred metres beneath the sea floor. To this end, effort during JR269B focused on acquiring controlled source electromagnetic (CSEM) geophysical survey data from two locations - one to the west of Prins Karl Forland, and one on the Vestnesa Ridge. Analysis of the data will aim to combine constraints on the electrical resistivity structure of the sea floor from this study with seismic constraints from previous studies through constrained and joint inversion methods. |
| Chief scientist | Martin C Sinha (National Oceanography Centre, Southampton) |
| Project | Arctic hydrate dissociation as a consequence of climate change: |
| Coordinating body | Natural Environment Research Council (NERC) |
| Cruise report |  (9.07 MB) |
| Ocean/sea areas | |
| General | Arctic Ocean |
| Specific | West Spitzbergen continental margin |
| Track charts | (1.35 MB) |
| Measurements | |
| Physical oceanography | |
| Surface measurements underway (T,S) | Quantity: activity duration in days = 18 Description: Standard meteorology and sea surface measurements underway |
| Bathythermograph | Quantity: number of profiles = 3 Description: XBT casts |
| CTD stations | Quantity: number of profiles = 4 Description: CTD casts |
| Current profiler (eg ADCP) | Quantity: track kilometres = 8 Description: ADCP measurements |
| Other physical oceanographic measurements | Quantity: track kilometres = 130 Description: Water column acoustic measurements for detecting bubble plumes |
| Meteorology | |
| Routine standard measurements | Quantity: activity duration in days = 18 Description: Standard meteorology and sea surface measurements underway |
| Atmospheric chemistry | Quantity: activity duration in days = 18 Description: Daily air samples |
| Atmospheric chemistry | Quantity: activity duration in days = 18 Description: Continuous air chemistry measurements for methane using PICARRO system |
| Geology and geophysics | |
| Bottom photography | Quantity: number of dives = 27 Description: HYBIS remotely operated vehicle dives |
| Geophysical measurements made at depth | Quantity: track kilometres = 60 Description: Controlled source electromagnetic survey |
| Multi-beam echosounding | Quantity: track kilometres = 130 Description: Swath bathymetry survey |
| Multichannel seismic reflection | Quantity: track kilometres = 115 Description: Multi-channel seismic reflection profiling |
| Other geological/geophysical measurements | Quantity: track kilometres = 60 Description: Controlled source electromagnetic survey |
