RRS James Clark Ross JR19990115 (JR39a)

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS James Clark Ross (74JC)
Cruise identifierJR19990115 (JR39a)
Cruise period1999-01-15 — 1999-02-09
Port of departureStanley, Falkland Islands (Malvinas)
Port of returnStanley, Falkland Islands (Malvinas)
ObjectivesThe very first scientific cruise of the James Clark Ross (JR01) acquired data along tracks in the northern Weddell Sea, designed to follow gravity ridges as far as 63°S (a second cruise, JR07, had been planned to undertake this work in areas further south but was cancelled). Two sections of the record, in particular, were of interest. The first was an apparent disruption of the spreading pattern, referred to informally as the 'kink', and the second was the abrupt termination of the ridge-trough pattern near 69°S, known as 'Anomaly-T'. Understanding the nature and significance of these features form the prime objectives for JR39a.
Chief scientistRoy Livermore (British Antarctic Survey)
Cruise reportRRS James Clark Ross JR19990115 (JR39a) cruise report jr39a.pdf (7.37 MB) 
Ocean/sea areas 
GeneralSouth Atlantic Ocean
SpecificWeddell Sea, South Sandwich Is.
Geology and geophysics 
Single channel seismic reflectionQuantity: number of surveys = 1
Description: A profile was made across the extinct axis of the West Scotia Ridge.
Single channel seismic reflectionQuantity: number of profiles = 4
Description: A number of seismic profiles were made during the cruise. The profiles showed the basement structure.
Magnetic measurementsQuantity: number of profiles = 1
Description: Magnetic profiles were made on both outward and return legs of the cruise.