RRS James Cook JC114
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS James Cook (740H) |
| Cruise identifier | JC114 |
| Cruise period | 2015-01-22 — 2015-03-06 |
| Status | Completed |
| Port of departure | Caldera, Costa Rica |
| Port of return | Balboa, Panama |
| Purpose | Research |
| Objectives | The OSCAR research programme in the Panama Basin consisted of three cruises on the RRS James Cook and a single cruise on the RV Sonne. The project aims to investigate the cooling of young oceanic crust by heat and mass flux between the solid Earth and the hydrosphere. Close to a mid-ocean ridge, rapid cooling is dominated by hydrothermal circulation of seawater through the porous and fractured basalt crust. The primary objective of this interdisciplinary project is to investigate the effects of this heat loss and hydrothermal circulation on both the solid Earth and the ocean. The data collected as part of the OSCAR project will be used to derive an integrated circulation model, constrained by geophysical, geological and physical oceanography data that will include flux through the seabed.
The primary objective of JC114 was to collect geophysical data at, and in the vicinity of, the Costa Rica Rift (CRR) (North Grid, NG) and Ocean Drilling Programme dill-hole 504B (South Grid, SG), including both high and low resolution normal incidence multichannel seismic reflection data, wide-angle seismic refraction using both ocean-bottom seismographs and the synthetic aperture (SAP) approach, potential field data (gravity and magnetics), swath bathymetry depth and backscatter data, and shallow sub-bottom profiler data. Then use the data to investigate the nature of the ocean layer 2a/2b boundary; the fluid flow in dykes both on and off the spreading axis; and the location and role of faults within layers 1 and 2. The programme collected seismic data throughout the study area and, in particular, within two grids located at the CRR and 504B drill-hole, connected by flow-line profiles. In addition, the cruise collected seismic data over the Ecuador Rift and swath bathymetry along the major fracture zones that segment the spreading ridge in this area. |
| Chief scientist | Richard W Hobbs (University of Durham, Department of Earth Sciences) |
| Cruise report |  (24.08 MB) |
| Ocean/sea areas | |
| General | North East Pacific Ocean (limit 180W) |
| Specific | Panama Basin (Costa Rica Ridge/ODP-504B/Sandra Ridge/Carnegie Ridge) |
| Track charts | (23.84 MB) |
| Measurements | |
| Physical oceanography | |
| Surface measurements underway (T,S) | Quantity: activity duration in days = 17 Description: The Surfmet system was run throughout the cruise. |
| Current profiler (eg ADCP) | Quantity: activity duration in days = 17 Description: Both hull mounted 75 kHz and 150 kHz ADCP systems were run during the cruise. |
| Other physical oceanographic measurements | Quantity: activity duration in days = 17 Description: The WaMos wave radar was run throughout the cruise. |
| Meteorology | |
| Routine standard measurements | Quantity: activity duration in days = 17 Description: The Surfmet system was run throughout the cruise. |
| Geology and geophysics | |
| Geophysical measurements made at depth | Quantity: number of profiles = 2 Description: Sound velocity profiles |
| Single-beam echosounding | Quantity: activity duration in days = 17 Description: The EA600 single beam echo sounder was run throughout the cruise. There are breaks in the data due to the acoustic instrumentation being isolated during OBS deployment and recovery. |
| Multi-beam echosounding | Quantity: activity duration in days = 17 Description: The EM120 multi-beam echo sounder was run throughout the cruise. There are breaks in the data due to the acoustic instrumentation being isolated during OBS deployment and recovery. |
| Single channel seismic reflection | Quantity: activity duration in days = 17 Description: The SBP120 Sub Bottom Profiler was run throughout the cruise. There are breaks in the data due to the acoustic instrumentation being isolated during OBS deployment and recovery. |
| Multichannel seismic reflection | Quantity: number of profiles = 30 Description: Multichannel reflection profiles. Dual airgun source (GI & BOLT) fired flip-flop. 4500m hydrophone array (360 channel). |
| Multichannel seismic reflection | Quantity: number of profiles = 11 Description: Multichannel reflection profiles. Dual airgun source (GI & BOLT) fired flip-flop. 1500m hydrophone array (120 channel). |
| Multichannel seismic reflection | Quantity: number of profiles = 5 Description: Multichannel reflection profiles. Triple airgun source (GI & BOLT + G-gun from SONNE) fired flip-flap-flop. 4500m hydrophone array (360 channel). |
| Multichannel seismic reflection | Quantity: number of profiles = 1 Description: Multichannel reflection profiles. Single airgun source (BOLT); 4500m hydrophone array (360 channel) |
| Multichannel seismic reflection | Quantity: number of profiles = 1 Description: Multichannel reflection profiles. Single airgun source (GI); 4500m hydrophone array (360 channel) |
| Seismic refraction | Quantity: number of deployments = 2 Description: Vertical hydrophone array. 4-component (4 hydrophone) to measure seismic energy from surface air-gun shots along multichannel seismic lines. |
| Seismic refraction | Quantity: number of deployments = 35 Description: Ocean-Bottom Seismograph. 4-component (hydrophone + 3 geophones) to measure seismic energy from surface air-gun shots. Synthetic Aperture Profile. |
| Seismic refraction | Quantity: number of deployments = 25 Description: Ocean-Bottom Seismograph. 4-component (hydrophone + 3 geophones) to measure seismic energy from surface air-gun shots along multichannel seismic lines at North Grid site. |
| Seismic refraction | Quantity: number of deployments = 25 Description: Ocean-Bottom Seismograph. 4-component (hydrophone + 3 geophones) to measure seismic energy from surface air-gun shots along multichannel seismic lines at South Grid site. |
| Seismic refraction | Quantity: number of deployments = 4 Description: Passive array. 4-component (hydrophone + 3 geophones) to measure natural seismicity. |
| Gravity measurements | Quantity: activity duration in days = 17 Description: Gravity – continuous data logging. Base station ties where made at Caldera and Balboa. |
| Magnetic measurements | Quantity: activity duration in days = 17 Description: Magnetics – data logged along all MCS profiles. |
