BODC Cruise Metadata Report for RRS James Cook (740H) cruise JC024

Introduction

This report collates information from the BODC cruise inventory and oceanographic databases. It presents

Cruise Inventory Information
A summary of BODC data holdings for the cruise from the
- National Oceanographic Database
- Projects Database
References - including cruise tracks and cruise reports

Cruise Inventory Information

Long name	RRS James Cook (740H) cruise JC024
Short name	JC024
Objectives and Narrative	Objectives 1. To determine the life cycle of an AVR (estimates range from 10ka to 500ka). 2. To test whether the AVR ha a common parental magma derived from a single pulse of mantle melt. 3. To test whether AVRs develop systematically with an evolving volcanic style (e.g., sheet flows > pillow ridges > central volcanoes). 4. To determine how, if at all, these different volcanic components are linked. Are they derived successively from separate magma reservoirs? Are lateral terraces fed from axial vents? 5. To examine whether effusion rate and volume vary with time during AVR development. Are they reflected in volcanic style, run-out length and eruptive position within the AVR? Summary JC24 involved the first use of the ROV Isis on an active mid-ocean ridge axis. We departed Ponta Delgada on 23 May 2008 and finished in Southampton on 28 June. A breakdown of the Isis winch on 9 June required us to return to Ponta Delgada to pick up a spare part, involving a loss of four days. Altogether, we spent approximately 9.5 days on passage and 26.5 days on station at 45� 30'N, including one day lost due to bad weather. We completed a 6-day TOBI survey extending approximately 30 km along axis, completely insonifying the AVR with both north- and south-looking sidescan and phase data and obtaining three-component magnetic data on 22 E-W tracks spaced 1.5 km apart. Ship-based EM120 multibeam echosounder and gravity data were logged throughout the cruise, and sea-surface magnetometer was logged during the passage to and from the study area and during the TOBI survey. Eleven Isis sampling and video imaging dives were completed, and a further two dives carried out detailed bathymetry surveys. 270 rock samples were acquired. A WHOI three-component magnetometer was carried on all Isis dives. The sidescan data were fully processed on board. In addition to the expected hummocky and flat-topped volcanoes, they revealed a number of lateral hummocky
Ship	RRS James Cook
Departure Port	Ponta Delgada, Portugal
Departure Date	2008-05-23
Arrival Port	Southampton, United Kingdom
Arrival Date	2008-06-28
Principal Scientist(s)	Roger C Searle (University of Durham, Department of Earth Sciences)
Responsible Organisation	University of Durham, Department of Earth Sciences
Associated Project(s)
IHB Sea Areas Visited	North East Atlantic Ocean (limit 40W)
Marsden Squares Visited	147
Work Area Description	Mid-Atlantic Ridge
Unable to lookup cruise bounds at this time
Work Area Bounding Polygon
Southern Limit	unknown
Northern Limit	unknown
Western Limit	unknown
Eastern Limit	unknown

Cruise Inventory Datasets

Physical oceanography
Other physical oceanographic measurements	Quantity: activity duration in hours = 31 Description: Tow-yo MAPR (Miniature Autonomous Plume Recorder) data, used for detecting hydrothermal plumes
Other physical oceanographic measurements	Quantity: activity duration in hours = 234 Description: ISIS MAPR data
Biology and fisheries
Other biological/fisheries measurement	Quantity: number of samples = 37 Description: Coral samples, for shore-based DNA analysis
Geology and geophysics
Bottom photography	Quantity: number of images = 9788 Description: ISIS still photos
Bottom photography	Quantity: activity duration in hours = 234 Description: ISIS video
Geophysical measurements made at depth	Quantity: survey square kilometres = 1200 Description: TOBI magnetics (3 component)
Geophysical measurements made at depth	Quantity: survey square kilometres = 8 Description: ISIS 3-component magnetics
Geophysical measurements made at depth	Quantity: survey square kilometres = 1200 Description: TOBI LSS (Light Scattering Sensor) data
Gravity measurements	Quantity: survey square kilometres = 1200 Description: Ship-based gravity
In-situ seafloor measurement/sampling	Quantity: number of samples = 272 Description: Rock samples, half of each to each PI, to be used for shore-based major- and trace-element geochemistry and U-series dating
Long/short range side scan sonar	Quantity: survey square kilometres = 1200 Description: TOBI sidescan sonar
Magnetic measurements	Quantity: survey square kilometres = 1200 Description: Sea-surface magnetics
Multi-beam echosounding	Quantity: survey square kilometres = 8 Description: ISIS MS2000 high-resolution bathymetry
Multi-beam echosounding	Quantity: survey square kilometres = 1200 Description: Ship-mounted EM120 with multibeam bathymetry
Other geological/geophysical measurements	Quantity: survey square kilometres = 1200 Description: TOBI phase bathymetry