RRS James Cook JC254
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS James Cook (740H) |
| Cruise identifier | JC254 |
| Cruise period | 2023-10-26 — 2023-11-29 |
| Status | Completed |
| Port of departure | Ponta Delgada, Portugal |
| Port of return | Bridgetown, Barbados |
| Purpose | Research |
| Objectives | Hydrothermal seafloor massive sulphide (SMS) deposits are formed by seawater circulating through the hot rocks beneath the ocean floor at mid-ocean ridges, where they strip out various elements, particularly metals, which are then deposited at the seabed as they emerge and cool at hot water vent systems. Most of these vent systems have been found within the active volcanic zone at the ridge axis. Recently, though, vent systems have been found at large faults which expose rocks of the oceanic mantle at the seabed, known as Oceanic Core Complexes (OCCs). These ultramafic-hosted seafloor massive sulphides (SMS) form some of the largest deposits known on the planet. The ULTRA project is an ambitious NERC funded strategic program that aims to characterise OCC hosted ultramafic seafloor massive sulphides, which are rich in Au, Cu, Ni and E-tech elements (including Co, Se and Pt). This research aims to understand the formation and evolution of mineralisation of different styles and to test the hypothesis that ?SMS deposits form extensive sub-surface mineralisation and undergo significant post-formational modification at and beneath the seafloor, under the influence of highly variable pH conditions as a result of interaction with ultramafic rocks and during serpentinisation.
This expedition is the second ULTRA expedition to the area. The first, ULTRA 1 (JC224) in March-April 2022 aimed to use the British Geological Survey Rock Drill 2 (RD2) to core different regions of mineralisation on the core complex. During ULTRA 1 four holes were drilled at the Semenov 1 site (3 shallow and one 20 m deep), numerous rocks and video transects were collected with Hybis, and five colonisation experiments were deployed, three at Semenov 1 and two and Semenov 2. The ULTRA 2 expedition has several different but linked aims: 1) Sample fluids from the boreholes drilled and capped in ULTRA 1, as well as from the active vents at Semenov 2; 2) Conduct high resolution seismic surveys to map the subsurface geometries of deposits; 3) Conduct electromagnetics surveys over the deposits to determine the extents of metalliferous mineralisation; 4) Collect additional rock samples and video footage to characterise the tectonic setting of the deposits; 5) Recover colonisation experiments deployed during the ULTRA 1 expedition; 6) Collect representative biological samples to characterise the differences between deposits. |
| Chief scientist | Isobel A Yeo (National Oceanography Centre, Southampton) |
| Project | Ultramafic-hosted mineral Resource Assessment (ULTRA) |
| Coordinating body | Natural Environment Research Council (NERC) |
| Ocean/sea areas | |
| General | South West Atlantic Ocean (limit 20W) |
| Track charts |  (0.14 MB) |
| Measurements | |
| Biology and fisheries | |
| Zoobenthos | Quantity: number of samples = 32 Description: Variety of marine specimens |
| Molluscs | Quantity: number of samples = 32 Description: Variety of marine specimens |
| Crustaceans | Quantity: number of samples = 32 Description: Variety of marine specimens |
| Geology and geophysics | |
| Core - rock | Quantity: number of cores = 2 Description: Rock drill cores |
| Core - rock | Quantity: number of cores = 24 Description: Gravity cores |
| Core - rock | Quantity: number of cores = 26 Description: Push cores |
| Bottom photography | Quantity: number of dives = 17 Description: ROV Video - ROV414 to ROV430 |
| Geophysical measurements made at depth | Quantity: number of surveys = 24 Description: OBX Geophysical Data Recordings over SEM1 and SEM4/5 |
| Multi-beam echosounding | Quantity: survey square kilometres = 450 Description: Multibeam bathymetry data were acquired throughout the duration of expedition JC254, including on the transits to and from the working area (outside of exclusive economic zones) and passively during other operations and transits between stations. |
| Other geological/geophysical measurements | Quantity: number of samples = 10 Description: Other fluid samples |
| Other geological/geophysical measurements | Quantity: number of samples = 24 Description: Fluid samples from Niskins bottles |
| Other geological/geophysical measurements | Quantity: number of surveys = 6 Description: CSEM surveys covering SEM1,3,4,5 |
| Other geological/geophysical measurements | Quantity: number of samples = 62 Description: Rock samples |
| Moorings, landers, buoys | |
| Geology and geophysics | |
| Seismic refraction | 13° 30' 49" N 44° 59' 22" W — SEM1 OBX deployment 2 04-Nov 06:41 |
| Seismic refraction | 13° 30' 46" N 44° 53' 18" W — SEM4 OBX recovery 4 18-Nov 14:17 |
| Seismic refraction | 13° 30' 32" N 44° 52' 50" W — SEM4 OBX deployment 8 12-Nov 01:48 |
| Seismic refraction | 13° 30' 18" N 44° 52' 50" W — SEM4 OBX recovery 7 19-Nov 18:58 |
| Seismic refraction | 13° 30' 46" N 44° 55' 12" W — SEM4 OBX recovery 16 21-Nov 06:51 |
| Seismic refraction | 13° 30' 47" N 44° 59' 28" W — SEM1 OBX deployment 1 04-Nov 05:55 |
| Seismic refraction | 13° 30' 50" N 44° 59' 18" W — SEM1 OBX deployment 3 04-Nov 07:37 |
| Seismic refraction | 13° 30' 51" N 44° 59' 15" W — SEM1 OBX deployment 4 04-Nov 08:17 |
| Seismic refraction | 13° 30' 52" N 44° 59' 11" W — SEM1 OBX deployment 5 04-Nov 09:40 |
| Seismic refraction | 13° 30' 54" N 44° 59' 4" W — SEM1 OBX deployment 6 04-Nov 10:30 |
| Seismic refraction | 13° 30' 47" N 44° 59' 28" W — SEM1 OBX recovery 1 07-Nov 16:48 |
| Seismic refraction | 13° 30' 49" N 44° 59' 21" W — SEM1 OBX recovery 2 07-Nov 17:45 |
| Seismic refraction | 13° 30' 50" N 44° 59' 18" W — SEM1 OBX recovery 3 07-Nov 18:17 |
| Seismic refraction | 13° 30' 51" N 44° 59' 15" W — SEM1 OBX recovery 4 07-Nov 18:54 |
| Seismic refraction | 13° 30' 54" N 44° 59' 4" W — SEM1 OBX recovery 6 07-Nov 20:21 |
| Seismic refraction | 13° 31' 2" N 44° 53' 3" W — SEM4 OBX deployment 1 11-Nov 01:17 |
| Seismic refraction | 13° 30' 44" N 44° 52' 52" W — SEM4 OBX deployment 2 11-Nov 04:09 |
| Seismic refraction | 13° 30' 30" N 44° 53' 3" W — SEM4 OBX deployment 3 11-Nov 05:52 |
| Seismic refraction | 13° 30' 18" N 44° 53' 17" W — SEM4 OBX deployment 5 11-Nov 09:27 |
| Seismic refraction | 13° 30' 2" N 44° 53' 3" W — SEM4 OBX deployment 6 11-Nov 10:56 |
| Seismic refraction | 13° 30' 18" N 44° 52' 50" W — SEM4 OBX deployment 7 12-Nov 00:23 |
| Seismic refraction | 13° 30' 31" N 44° 53' 17" W — SEM4 OBX deployment 9 12-Nov 04:16 |
| Seismic refraction | 13° 30' 43" N 44° 53' 42" W — SEM4 OBX deployment 10 12-Nov 06:54 |
| Seismic refraction | 13° 30' 18" N 44° 53' 54" W — SEM4 OBX deployment 11 12-Nov 09:28 |
| Seismic refraction | 13° 30' 45" N 44° 54' 14" W — SEM4 OBX deployment 12 12-Nov 12:13 |
| Seismic refraction | 13° 30' 18" N 44° 54' 30" W — SEM4 OBX deployment 13 13-Nov 02:02 |
| Seismic refraction | 13° 30' 44" N 44° 54' 44" W — SEM4 OBX deployment 14 13-Nov 04:32 |
| Seismic refraction | 13° 31' 2" N 44° 55' 10" W — SEM4 OBX deployment 15 13-Nov 06:25 |
| Seismic refraction | 13° 30' 46" N 44° 55' 12" W — SEM4 OBX deployment 16 13-Nov 08:20 |
| Seismic refraction | 13° 30' 2" N 44° 55' 11" W — SEM4 OBX deployment 18 13-Nov 11:01 |
| Seismic refraction | 13° 31' 1" N 44° 53' 3" W — SEM4 OBX recovery 1 18-Nov 11:52 |
| Seismic refraction | 13° 30' 44" N 44° 52' 52" W — SEM4 OBX recovery 2 18-Nov 13:00 |
| Seismic refraction | 13° 30' 29" N 44° 53' 4" W — SEM4 OBX recovery 3 18-Nov 18:12 |
| Seismic refraction | 13° 30' 18" N 44° 53' 17" W — SEM4 OBX recovery 5 18-Nov 20:24 |
| Seismic refraction | 13° 30' 2" N 44° 53' 3" W — SEM4 OBX recovery 6 19-Nov 15:52 |
| Seismic refraction | 13° 30' 31" N 44° 52' 51" W — SEM4 OBX recovery 8 19-Nov 22:09 |
| Seismic refraction | 13° 30' 31" N 44° 53' 17" W — SEM4 OBX recovery 9 18-Nov 19:58 |
| Seismic refraction | 13° 30' 43" N 44° 53' 43" W — SEM4 OBX recovery 10 21-Nov 21:39 |
| Seismic refraction | 13° 30' 18" N 44° 53' 54" W — SEM4 OBX recovery 11 22-Nov 07:10 |
| Seismic refraction | 13° 30' 44" N 44° 54' 14" W — SEM4 OBX recovery 12 22-Nov 10:44 |
| Seismic refraction | 13° 30' 18" N 44° 54' 30" W — SEM4 OBX recovery 13 20-Nov 21:11 |
| Seismic refraction | 13° 30' 44" N 44° 54' 44" W — SEM4 OBX recovery 14 21-Nov 00:44 |
| Seismic refraction | 13° 31' 2" N 44° 55' 11" W — SEM4 OBX recovery 15 21-Nov 04:36 |
| Seismic refraction | 13° 30' 18" N 44° 55' 10" W — SEM4 OBX recovery 17 21-Nov 10:22 |
| Seismic refraction | 13° 30' 2" N 44° 55' 11" W — SEM4 OBX recovery 18 21-Nov 11:29 |
| Seismic refraction | 13° 30' 18" N 44° 55' 10" W — SEM4 OBX deployment 17 13-Nov 09:58 |
| Seismic refraction | 13° 30' 45" N 44° 53' 18" W — SEM4 OBX deployment 4 11-Nov 07:33 |
| Seismic refraction | 13° 30' 52" N 44° 59' 11" W — SEM1 OBX recovery 5 07-Nov 19:35 |
