Cruise inventory

RRS Discovery D208

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Discovery (74E3)
Cruise identifierD208
Cruise period1994-04-19 — 1994-05-20
StatusCompleted
Port of departurePort Louis, Mauritius
Port of returnPort Louis, Mauritius
PurposeResearch
ObjectivesTo study the crustal structure of the Southwest Indian Ridge
Chief scientistTim A Minshull (University of Cambridge Department of Earth Sciences)
Ocean/sea areas 
GeneralIndian Ocean
SpecificSouthwest Indian Ocean, Atlantis II fracture zone, SW Indian Ridge at 66E
Measurements 
Physical oceanography 
BathythermographQuantity: number of profiles = 11
Description: XBT drops to 750m depth
Geology and geophysics 
DredgeQuantity: number of hauls = 16
Description: rock dredges in SW Indian ridge rift valley, fresh and altered basalts and mud
Geophysical measurements made at depthQuantity: number of profiles = 2
Description: velocimeter dips, to 3000m at 32 45S, 57 4E and to 3950m at 25 28S, 66 25E
Single-beam echosoundingQuantity: track kilometres = 6000
Description: Simrad EA500 10kHz narrow beam echo sounder, automatically picked
Multichannel seismic reflectionQuantity: track kilometres = 1700
Description: 8-channel data, 100m receiver/shot spacing,to 12s 2-way time, 10 gun
Seismic refractionQuantity: number of deployments = 20
Description: Free floating Spartan AN/SSQ-57B sonobuoys, depl. during reflection profiling
Gravity measurementsQuantity: track kilometres = 6000
Description: Lacoste and Romberg shipboard gravimeter, sampled at 30s intervals
Magnetic measurementsQuantity: track kilometres = 4000
Description: Barringer Research M123 total field proton magnetometer, with fish
Moorings, landers, buoys 
Geology and geophysics 
Seismic refraction32° 43' 59" S  56° 51' 0" E —
Seismic refraction27° 49' 0" S  65° 58' 59" E — also at 27 41.0S, 065 59.0E
Seismic refraction32° 45' 0" S  57° 4' 0" E —
Seismic refraction32° 45' 0" S  57° 27' 0" E —
Seismic refraction27° 34' 59" S  65° 46' 59" E —
Seismic refraction27° 34' 0" S  66° 10' 0" E —
Seismic refraction32° 55' 59" S  57° 16' 59" E — Ocean bottom seismometers, depl. and recovered.
Seismic refraction32° 45' 0" S  57° 16' 59" E — 1st depl. Julian days 112-113; recovered days 118-120
Seismic refraction32° 40' 59" S  57° 16' 59" E — 2nd depl. Julian days 127-128; recovered days 133-134
Seismic refraction32° 31' 59" S  57° 16' 59" E — Sample rate 128Hz, recording air gun shots
Seismic refraction27° 34' 59" S  65° 58' 0" E —
Seismic refraction27° 33' 0" S  66° 22' 59" E —
Seismic refraction27° 25' 59" S  66° 57' 0" E —
Seismic refraction27° 40' 59" S  65° 46' 0" E —
Seismic refraction32° 43' 59" S  57° 37' 59" E —